ARISTOTELIAN THERMODYNAMICSARISTOTELIAN THERMODYNAMICS

KATALIN MARTINÁSKATALIN MARTINÁS

Dept. for Low Temp. Physics, Roland Eötvös University, Dept. for Low Temp. Physics, Roland Eötvös University, Puskin u. 5-7, Budapest, H-1088, HungaryPuskin u. 5-7, Budapest, H-1088, Hungary

ABSTRACTABSTRACT

Our aim is to show, that Aristotle's physics has a message for us.Our aim is to show, that Aristotle's physics has a message for us. Conceptually it is a General Irreversible Phenomenology, in closeConceptually it is a General Irreversible Phenomenology, in close relation to modern irreversible thermodynamics. relation to modern irreversible thermodynamics.

1. Introduction1. Introduction

As the modern physics (mechanics) originated from Aristotle in the form ofAs the modern physics (mechanics) originated from Aristotle in the form of negation, we are taught, that Aristotle's physics is a premature, wrongnegation, we are taught, that Aristotle's physics is a premature, wrong mechanics, and nothing more. To show this generally accepted opinion wemechanics, and nothing more. To show this generally accepted opinion we cite Delbrückcite Delbrück11, who admired Aristotle, as a biologist: , who admired Aristotle, as a biologist:

"(Aristotle's) Physics was practically non-existent and also there was"(Aristotle's) Physics was practically non-existent and also there was very little interest along that line. Nobody would deny that Aristotle'svery little interest along that line. Nobody would deny that Aristotle's physics was pretty much of a catastrophe while his biology abounds inphysics was pretty much of a catastrophe while his biology abounds in aggressive speculative analysis."aggressive speculative analysis."

We do it. We say, that Aristotle's physics is a very interesting, very modernWe do it. We say, that Aristotle's physics is a very interesting, very modern approach of problems, but the mechanical interpretation. Nevertheless, it isapproach of problems, but the mechanical interpretation. Nevertheless, it is the opinion of Delbrück too, as later he added:the opinion of Delbrück too, as later he added:

"I should like to suggest, furthermore, that the reason for the lack of"I should like to suggest, furthermore, that the reason for the lack of appreciation among scientists for Aristotle's scheme lies in our havingappreciation among scientists for Aristotle's scheme lies in our having blinded for three hundred years by the Newtonian view of the world."blinded for three hundred years by the Newtonian view of the world."11

Our first step to Aristotle's physics was triggered by a very excellent book ofOur first step to Aristotle's physics was triggered by a very excellent book of Károly Károly

Simonyi, "The Cultural History of Physics"Simonyi, "The Cultural History of Physics"22, where he interpreted the, where he interpreted the dynamics of Aristotle's physics as the dynamics of movement with friction. Itdynamics of Aristotle's physics as the dynamics of movement with friction. It gave us the idea, that the Aristotelian dynamics is the dynamics ofgave us the idea, that the Aristotelian dynamics is the dynamics of thermodynamics. We read some works of Aristotle on physics, (Physicsthermodynamics. We read some works of Aristotle on physics, (Physics33,, MeteorologicaMeteorologica44, De Generatione et Corruptione, De Generatione et Corruptione55, and De Caelo, and De Caelo66, the very, the very books, and not the interpretations) and what we found there, it was abooks, and not the interpretations) and what we found there, it was a wonderful `antique thermodynamics'.wonderful `antique thermodynamics'.77 To get it, one has to avoid the usual To get it, one has to avoid the usual mechanical interpretations, and to try to use the original Aristotelianmechanical interpretations, and to try to use the original Aristotelian meaning of the concepts, and then the result will be a very `modern' naturalmeaning of the concepts, and then the result will be a very `modern' natural philosophy. We argue, that the widely accepted mechanical interpretationphilosophy. We argue, that the widely accepted mechanical interpretation reflects only a simplified version of the Aristotelian natural philosophy. Thereflects only a simplified version of the Aristotelian natural philosophy. The basic factor of the Aristotelian `physics' is the recognition of thebasic factor of the Aristotelian `physics' is the recognition of the contradiction of the `reversible' processes in the heaven, and thecontradiction of the `reversible' processes in the heaven, and the `irreversibility' of the sublunar world, and because of the irreversibility of`irreversibility' of the sublunar world, and because of the irreversibility of natural motion the only possible interpretation of Aristotelian physics can benatural motion the only possible interpretation of Aristotelian physics can be found in the framework of modern irreversible thermodynamics. We call itfound in the framework of modern irreversible thermodynamics. We call it Aristotelian thermodynamics. Maybe for the Aristotle's physics this name isAristotelian thermodynamics. Maybe for the Aristotle's physics this name is not right, as the canonical meaning of modern thermodynamics is restrictednot right, as the canonical meaning of modern thermodynamics is restricted to the mechanical theory of heat, to a small part of statistical physics. In thisto the mechanical theory of heat, to a small part of statistical physics. In this approach Aristotelian physics is not thermodynamics, moreover it is notapproach Aristotelian physics is not thermodynamics, moreover it is not physics at all. physics at all.

Our approach to thermodynamics follows the line of DuhemOur approach to thermodynamics follows the line of Duhem88 and Tisza and Tisza 99, i.e., i.e. it is a general theory of irreversible systems, where the key concepts are:it is a general theory of irreversible systems, where the key concepts are: irreversibilityirreversibility1010, equilibrium, inhomogeneity, force, current... The traces of the concepts of, equilibrium, inhomogeneity, force, current... The traces of the concepts of reversibility and irreversibility can be found in the antiquity, but the `clearreversibility and irreversibility can be found in the antiquity, but the `clear concept' of irreversibility appears only in the Aristotelian Physics.concept' of irreversibility appears only in the Aristotelian Physics.

The irreversibility appears in two levels in Aristotle's physics. The naturalThe irreversibility appears in two levels in Aristotle's physics. The natural movement is a process, where the body tends to occupy its natural position,movement is a process, where the body tends to occupy its natural position, i.e. without external effects this process must not go from the final state toi.e. without external effects this process must not go from the final state to the initial state. The natural movement is an irreversible process, where thethe initial state. The natural movement is an irreversible process, where the natural position conceptually agrees the equilibrium state ofnatural position conceptually agrees the equilibrium state of thermodynamics, as from it without external effects there is no process. Thethermodynamics, as from it without external effects there is no process. The law of natural movement corresponds to the Second Law oflaw of natural movement corresponds to the Second Law of thermodynamics. In fact, Aristotle meets the problem of `heat death' (in athermodynamics. In fact, Aristotle meets the problem of `heat death' (in a closed world after infinite time equilibrium state develops). In a closedclosed world after infinite time equilibrium state develops). In a closed Aristotelian sublunar world everything would occupy its natural position, andAristotelian sublunar world everything would occupy its natural position, and no further movement would be possible. The Aristotelian solution for theno further movement would be possible. The Aristotelian solution for the `heat death' problem is the `unmoved mover', who ensures the continuous`heat death' problem is the `unmoved mover', who ensures the continuous 'kicking out' of the natural position, ie. He continuously provides the'kicking out' of the natural position, ie. He continuously provides the 'negentropy flux' through the Sun rays, to prevent the final stopping of the'negentropy flux' through the Sun rays, to prevent the final stopping of the sublunar world, to avoid the 'heat death', he is an Entropic God.sublunar world, to avoid the 'heat death', he is an Entropic God.

The other appearance of irreversibility (closely related to the first) is in hisThe other appearance of irreversibility (closely related to the first) is in his dynamics. It is evident, that formally the Aristotelian dynamics is the samedynamics. It is evident, that formally the Aristotelian dynamics is the same as that of thermodynamics. In both cases the change of the stateas that of thermodynamics. In both cases the change of the state characterizing quantities are proportional to the Force. Nevertheless, thecharacterizing quantities are proportional to the Force. Nevertheless, the analogy is deeper. The thermodynamic interpretation of the terms appearinganalogy is deeper. The thermodynamic interpretation of the terms appearing in his dynamics leads a more concise reconstruction, with the disappearancein his dynamics leads a more concise reconstruction, with the disappearance of lot of well known paradoxes.of lot of well known paradoxes.

******

The standard books on the history of thermodynamics usually do notThe standard books on the history of thermodynamics usually do not mention Aristotle's physics, and the books on Aristotle's physics do notmention Aristotle's physics, and the books on Aristotle's physics do not mention thermodynamics. It does not mean, that there was no relation in themention thermodynamics. It does not mean, that there was no relation in the past. Nevertheless the deep investigation of the scientific literature shows,past. Nevertheless the deep investigation of the scientific literature shows, that the Aristotle's physics had effect on the development ofthat the Aristotle's physics had effect on the development of thermodynamics, nevertheless they are mainly forgotten. The connectionthermodynamics, nevertheless they are mainly forgotten. The connection between Boltzmann and Aristotle and Thomas d'Aquin was investigated bybetween Boltzmann and Aristotle and Thomas d'Aquin was investigated by Robert Locqueneux et al.Robert Locqueneux et al.1111 In France the works of Rankine and Duhem show the Aristotelian effect.In France the works of Rankine and Duhem show the Aristotelian effect. Rankine's referring to Aristotle is considered as mechanics, but the fullRankine's referring to Aristotle is considered as mechanics, but the full statement is as follows:statement is as follows:

"The step which I took in 1853, of applying the distinction between"The step which I took in 1853, of applying the distinction between "Actual Energy" and "Potential Energy", not to motion and mechanical"Actual Energy" and "Potential Energy", not to motion and mechanical power alone, but power alone, but to all kinds of physical phenomenato all kinds of physical phenomena, was suggested to, was suggested to me, I think, by Aristotle's use of the words dynamis and energeia."me, I think, by Aristotle's use of the words dynamis and energeia."1212

The relation between Duhem and Aristotelian physics is more profound. TheThe relation between Duhem and Aristotelian physics is more profound. The New Physics based upon Thermodynamics is the physics of qualitiesNew Physics based upon Thermodynamics is the physics of qualities1313, where, where the motion is used in the Aristotelian sense. Duhem's aim on the new physicsthe motion is used in the Aristotelian sense. Duhem's aim on the new physics (thermodynamics)(thermodynamics)

"is the daughter of Aristotle, in that it is a theory of qualities, it is also a"is the daughter of Aristotle, in that it is a theory of qualities, it is also a daughter of Descartes, in that it is a Universal Mathematics; in it theredaughter of Descartes, in that it is a Universal Mathematics; in it there begin to converge the two tendencies which, for so long, have drawnbegin to converge the two tendencies which, for so long, have drawn Science and Nature in opposite directions."Science and Nature in opposite directions."88

Nevertheless Duhem's philosophy, methodology did not become widelyNevertheless Duhem's philosophy, methodology did not become widely accepted, his program of New Physics was not continued. His physics ofaccepted, his program of New Physics was not continued. His physics of Quality is loved, admired by a relatively narrow group of science historiansQuality is loved, admired by a relatively narrow group of science historians and philosophers, nevertheless the scientific community almost totallyand philosophers, nevertheless the scientific community almost totally ignores him.ignores him.

The usual thermodynamic constructions are very timid, they do not aim theThe usual thermodynamic constructions are very timid, they do not aim the generality of Aristotelian Cosmology, or that of Duhem's New Mechanics.generality of Aristotelian Cosmology, or that of Duhem's New Mechanics. Instead of generality it developed to the other direction, as now the mostInstead of generality it developed to the other direction, as now the most popular view asserts, that thermodynamics is the daughter of statisticalpopular view asserts, that thermodynamics is the daughter of statistical

physics, and so the granddaughter of the old mechanics. Reading Duhemphysics, and so the granddaughter of the old mechanics. Reading Duhem and Aristotle can help to find the real place and origin of thermodynamics.and Aristotle can help to find the real place and origin of thermodynamics.

The dawn of thermodynamics varies from the prehistoric man to the end ofThe dawn of thermodynamics varies from the prehistoric man to the end of XIX. century, depending on the definition of its scope. The generallyXIX. century, depending on the definition of its scope. The generally accepted version starts thermodynamics with Rumford, Mayer, Carnot, soaccepted version starts thermodynamics with Rumford, Mayer, Carnot, so with the XIX. century. Nevertheless the history is always changed along thewith the XIX. century. Nevertheless the history is always changed along the development of the science. This statement is especially valid fordevelopment of the science. This statement is especially valid for thermodynamics. The definition of the scope of thermodynamics is notthermodynamics. The definition of the scope of thermodynamics is not unique. Some of the accepted definitions:unique. Some of the accepted definitions:

Definition aDefinition a: (Definition used by the engineers) : (Definition used by the engineers) Thermodynamics describes the thermal phenomena, Thermodynamics describes the thermal phenomena, the key concepts are: heat, work, temperature (hot and cold).the key concepts are: heat, work, temperature (hot and cold).

This definition needs a distinction between the everyday experiences andThis definition needs a distinction between the everyday experiences and science, and depending on this level, one can get a thermoscience, and depending on this level, one can get a thermodynamics which isdynamics which is the first science, starting with the prehistoric man, or one of the latest,the first science, starting with the prehistoric man, or one of the latest, starting with the calorimetry (1770).starting with the calorimetry (1770).

Definition Definition b: (Most generally accepted version)b: (Most generally accepted version)Thermodynamics is the science of thermal interaction, the keyThermodynamics is the science of thermal interaction, the key concepts are: energy, entropy, temperature..concepts are: energy, entropy, temperature..

The definition b is the most generally acceptThe definition b is the most generally accepted version, in this caseed version, in this case thermodynamics began in the XIX. century, and some prethermodynamthermodynamics began in the XIX. century, and some prethermodynamicsics with Galileo Galilei.with Galileo Galilei.

Definition Definition c: (Used by the statistical physicists)c: (Used by the statistical physicists)Thermodynamics equals the basic laws, their exact statement can beThermodynamics equals the basic laws, their exact statement can be done only starting from statistical mechanics.done only starting from statistical mechanics.

The modern history starts with Boltzmann, and the paragraph b contains theThe modern history starts with Boltzmann, and the paragraph b contains the prehistory of thermodynamics. prehistory of thermodynamics.

Definition Definition d: (Used by the phenomenologists)d: (Used by the phenomenologists)Thermodynamics is a general theory of irreversible systems,Thermodynamics is a general theory of irreversible systems,the key concepts are: irreversibility, equilibrium, inhomogeneity, force,the key concepts are: irreversibility, equilibrium, inhomogeneity, force, current...current...

In this case the history begins with the appearance of irreversibility.In this case the history begins with the appearance of irreversibility.

In Table I. we summarizes the different approaches to the scope ofIn Table I. we summarizes the different approaches to the scope of thermodynamics with the relevant key concepts. We tried to define thethermodynamics with the relevant key concepts. We tried to define the relevant position of thermodynamics in the branches of physics, and relevant position of thermodynamics in the branches of physics, and the starting point of the science of thermodynamics, belonging to thethe starting point of the science of thermodynamics, belonging to the different definitions of the scope.different definitions of the scope.

Table ITable I

scopescope key conceptskey concepts history history startsstarts

similar tosimilar to

science of science of thermal thermal phenomenaphenomena

heat, work, heat, work, temperature (hot temperature (hot and cold).and cold).

prehistoricprehistoric--manman

electro-electro-technicstechnics

science of science of thermal thermal interactioninteraction

energy, entropy, energy, entropy, temperature..temperature..

XIX. XIX. centurycentury

electro-electro-dynamicsdynamics

the four basic the four basic lawslaws

energy, entropy, energy, entropy, temperature..temperature..

XIX. XIX. centurycentury

part of part of statistical statistical physicsphysics

general theory general theory of irreversible of irreversible systemssystems

irreversibility,irreversibility,equilibrium, equilibrium, inhomogeneity, inhomogeneity, force, current..force, current..

antiquityantiquity mechanicsmechanicsaa

aa denotes, that in this approach thermodynamics and mechanics are the denotes, that in this approach thermodynamics and mechanics are the irreversible and reversible general disciplines in physics.irreversible and reversible general disciplines in physics.

In the different definitions of the scope of thermodynamics the AristotelianIn the different definitions of the scope of thermodynamics the Aristotelian physics can be interpreted, as an antique thermodynamics, in the followingphysics can be interpreted, as an antique thermodynamics, in the following senses:senses:

Definition aDefinition a: The thermodynamics is the science of thermal phenomena. : The thermodynamics is the science of thermal phenomena. Aristotle' physics is thermodynamics, as the hot and cold are the activeAristotle' physics is thermodynamics, as the hot and cold are the active qualities, these principles have the organizing role. qualities, these principles have the organizing role.

Nearly all the experiences that are essential to thermodynamics wereNearly all the experiences that are essential to thermodynamics were described, further, his Meteorology can be considered as an antique applieddescribed, further, his Meteorology can be considered as an antique applied thermodynamics, e.g. the concept of heat capacity is also present.thermodynamics, e.g. the concept of heat capacity is also present.Definition b: Definition b: The thermodynamics is the science of thermal interaction.The thermodynamics is the science of thermal interaction.

There are some effort to find the antique equivalents of energy,There are some effort to find the antique equivalents of energy, entropy, nevertheless, we are positive, that in this senseentropy, nevertheless, we are positive, that in this sense thermodynamics do not exist before the XIX. century.thermodynamics do not exist before the XIX. century.

Definition c: The content of thermodynamics equals the 4 basic laws, and itDefinition c: The content of thermodynamics equals the 4 basic laws, and it is ensured is ensured by the statistical physics.by the statistical physics.As Aristotle's physics is not atomistic, there is no way to find aAs Aristotle's physics is not atomistic, there is no way to find a correspondence.correspondence.

Definition d: The thermodynamics is a general theory of irreversible systems.Definition d: The thermodynamics is a general theory of irreversible systems.

This This definition emphasizes the dynamical structure ofdefinition emphasizes the dynamical structure of thermodynamics. thermodynamics. It is easy to demonstrate, that the dynamics of AristoteIt is easy to demonstrate, that the dynamics of Aristotelian physics islian physics is analogousanalogous

to that of thermodynamics. The key concepts such as equilibrium,to that of thermodynamics. The key concepts such as equilibrium, inhomogeneity, irreversibility, driving force, or self-organization can beinhomogeneity, irreversibility, driving force, or self-organization can be identified in his dynamical views.identified in his dynamical views.

This comparison shows, that the most popular definitions of the scope ofThis comparison shows, that the most popular definitions of the scope of thermodynamics (case b and c) exclude the possibility to interpretthermodynamics (case b and c) exclude the possibility to interpret Aristotelian physics as thermodynamics, while definitions of engineers andAristotelian physics as thermodynamics, while definitions of engineers and phenomenologists imply its existence. In the following, we wish to proof thatphenomenologists imply its existence. In the following, we wish to proof that the Aristotelian physics is thermodynamics in the sense ofthe Aristotelian physics is thermodynamics in the sense of phenomenologists. phenomenologists.

2. The basic concepts of Aristotelian Physics2. The basic concepts of Aristotelian Physics

The Aristotelian physics and the modern one are incommensurable. It is notThe Aristotelian physics and the modern one are incommensurable. It is not mechanics, it is not thermodynamics. What one can look for, is the best fit.mechanics, it is not thermodynamics. What one can look for, is the best fit. To help it, in Table II the basic concepts of mechanics, thermodynamics andTo help it, in Table II the basic concepts of mechanics, thermodynamics and Aristotle's physics in mechanical interpretation, (column 3), and in ourAristotle's physics in mechanical interpretation, (column 3), and in our interpretation (column 4), supported by the Aristotelian definition and use ofinterpretation (column 4), supported by the Aristotelian definition and use of concepts. concepts.

Table IITable II

MechanicsMechanics Thermo-Thermo-dynamicsdynamics

Aristotle'Aristotle'Physics Physics Usual Usual interpreta-interpreta-tiontion

Aristotle'Aristotle'Physics Physics (Ross (Ross translation)translation)

StateStateVariablesVariables

time, time, place,place,mass,mass,velocityvelocity

time, time, place, place, extensives,extensives,intensivesintensives

time, placetime, place time, place, time, place, quantity, quantity, qualityquality

Dynamic Dynamic variablesvariables

force, force, acceleratioaccelerationn

currentcurrentresistance,resistance,generalizegeneralized forced force

velocity,velocity,forceforce

change of change of magnitude,magnitude,resistance,resistance,forceforce

`final `final state'state'

equilibriumequilibrium statestate

natural natural positionposition

Time Time behavior behavior

reversiblereversible irreversibleirreversible cycliccyclic irreversibleirreversible

Here we summarize the Aristotelian definitions of the physical concepts. Here we summarize the Aristotelian definitions of the physical concepts. MovementMovementThe original Aristotelian definition of movement is as follows:The original Aristotelian definition of movement is as follows:

"The fulfillment of what exists potentially, in so far as it exists"The fulfillment of what exists potentially, in so far as it exists potentially, is motion potentially, is motion -- namely, of what is alterable qua alterable, namely, of what is alterable qua alterable, alteration: of what can be increased and its opposite what can bealteration: of what can be increased and its opposite what can be decreased (there is no common name), increase and decrease: of whatdecreased (there is no common name), increase and decrease: of what can come to be and can pass away, coming to be and passing away: ofcan come to be and can pass away, coming to be and passing away: of what can be carried along, locomotion."(AP 201 b)what can be carried along, locomotion."(AP 201 b)

According to this, movement (or change) can be divided into 4 types: According to this, movement (or change) can be divided into 4 types: a) substantial change (coming to be and passing away); a) substantial change (coming to be and passing away); b) quantitative change (increase and decrease); b) quantitative change (increase and decrease); c) qualitative change (such as the change of color); c) qualitative change (such as the change of color); d) locomotion (movement where place is changed). d) locomotion (movement where place is changed).

By Aristotle in all movements we can identify the following factors: By Aristotle in all movements we can identify the following factors: - mover or movent (action), - mover or movent (action), - moved (passivity), - moved (passivity), - moving in something (date), and - moving in something (date), and - moving to somewhere (relation) (AP 249 b) - moving to somewhere (relation) (AP 249 b)

The movement is always in place and time.The movement is always in place and time.PlacePlace: The Aristotelian definition of place contains, the followings:: The Aristotelian definition of place contains, the followings:

"Place is what contains that of which it is the place. ...all place admits"Place is what contains that of which it is the place. ...all place admits of the distinction of up and down, and each of the bodies is naturallyof the distinction of up and down, and each of the bodies is naturally carried to its appropriate place and rests there, and this makes thecarried to its appropriate place and rests there, and this makes the place either up or down." (AP 210 b)place either up or down." (AP 210 b)

TimeTime: The Aristotelian time is something that encompasses everything and: The Aristotelian time is something that encompasses everything and has a power has a power over everything - except over what is eternal andover everything - except over what is eternal and what `is not' and can never be.what `is not' and can never be.1414

Definitions of time given by Aristotle are:Definitions of time given by Aristotle are:"Time ..is not held to be made up of `nows'" (AP 218 a)"Time ..is not held to be made up of `nows'" (AP 218 a)

and the universality, homogeneity of time is formulated, asand the universality, homogeneity of time is formulated, as"while the movements are different and separate, the time is"while the movements are different and separate, the time is everywhere the same, because the number of equal and simultaneouseverywhere the same, because the number of equal and simultaneous movements is everywhere one and the same."(AP 223 a) movements is everywhere one and the same."(AP 223 a)

The irreversibility is clearly stated too:The irreversibility is clearly stated too:"For time is by its nature the cause rather of decay, since it is the"For time is by its nature the cause rather of decay, since it is the number of change, and change removes what is." (AP 221 a)number of change, and change removes what is." (AP 221 a)

In time all things come into being and pass away, that's why the time is mostIn time all things come into being and pass away, that's why the time is most stupid of all things, said Aristotle:stupid of all things, said Aristotle:

"It is clear then that it must be in itself, as we said before, the"It is clear then that it must be in itself, as we said before, the condition of destruction rather than of coming into being and onlycondition of destruction rather than of coming into being and only incidentally of coming into being, and of being. A sufficient evidence ofincidentally of coming into being, and of being. A sufficient evidence of this is that nothing comes into being without itself moving some howthis is that nothing comes into being without itself moving some how and acting, but a thing can be destroyed even if it does not move atand acting, but a thing can be destroyed even if it does not move at all."(AP 222 b)all."(AP 222 b)

Quantity:Quantity: Quantity is measured by magnitude, and Quantity is measured by magnitude, and"the motion in respect of Quantity is called increase or decrease, the"the motion in respect of Quantity is called increase or decrease, the motion in the direction of complete magnitude is increase" (AP 226 a)motion in the direction of complete magnitude is increase" (AP 226 a)

Quality:Quality: Quality is a property of substance (in that sense that which Quality is a property of substance (in that sense that which constitutes a specific distinction in a quality), and constitutes a specific distinction in a quality), and

"in virtue of which a thing is said to be acted on or be incapable of"in virtue of which a thing is said to be acted on or be incapable of being acted on." (AP 226 a)being acted on." (AP 226 a)

Velocity:Velocity: Aristotle introduced a concept, translated to velocity, nevertheless Aristotle introduced a concept, translated to velocity, nevertheless it does not fit to the modern concept of velocity, it is the it does not fit to the modern concept of velocity, it is the change of change of magnitudemagnitude. .

"two things are of the same velocity if they occupy an equal time in"two things are of the same velocity if they occupy an equal time in accomplishing a certain equal amount of motion."(AP 249 b) accomplishing a certain equal amount of motion."(AP 249 b) "two things are of equal velocity if in an equal time they traverse the"two things are of equal velocity if in an equal time they traverse the same mag-nitude: and when I call it the same I mean that it containssame mag-nitude: and when I call it the same I mean that it contains no specific difference and therefore no difference in the motion thatno specific difference and therefore no difference in the motion that takes place over it."(AP 249 a) takes place over it."(AP 249 a)

The Aristotelian `velocity' is defined by the relation between the change of aThe Aristotelian `velocity' is defined by the relation between the change of a magnitude, defined in the initial and final state, and the time needed for themagnitude, defined in the initial and final state, and the time needed for the change. That is why the acceleration, the `change of change' has nochange. That is why the acceleration, the `change of change' has no meaning in his physics (again a similarity with thermodynamics, as in themeaning in his physics (again a similarity with thermodynamics, as in the classical irreversible thermodynamics the time derivative of the currents areclassical irreversible thermodynamics the time derivative of the currents are not used). not used).

The above definitions clearly state, that in Aristotle's physics the state of aThe above definitions clearly state, that in Aristotle's physics the state of a system is characterized by the time, place, magnitudes (quantity) andsystem is characterized by the time, place, magnitudes (quantity) and qualities, which are very near to the thermodynamic extensive and intensivequalities, which are very near to the thermodynamic extensive and intensive parameters, and the velocity is not defined as a state parameter. parameters, and the velocity is not defined as a state parameter.

The Aristotelian dynamics:The Aristotelian dynamics:

Aristotle distinguished between Aristotle distinguished between -the movement of living creatures and inanimate bodies; -the movement of living creatures and inanimate bodies; -the movement of celestial and earthly bodies; -the movement of celestial and earthly bodies; -natural and constrained movement. -natural and constrained movement.

The circular movement of celestial bodies and the movement of earthlyThe circular movement of celestial bodies and the movement of earthly things striving upwards and down is natural, while constrained movement isthings striving upwards and down is natural, while constrained movement is produced when one body is directly influenced by another one, and on theproduced when one body is directly influenced by another one, and on the movement of the living creatures Aristotle wrote:movement of the living creatures Aristotle wrote:

"Everything that is in motion must be moved by something. For if it has"Everything that is in motion must be moved by something. For if it has not the source of its motion in itself it is evident that it is moved bynot the source of its motion in itself it is evident that it is moved by something other than itself, for there must be something else thatsomething other than itself, for there must be something else that moves it."(AP 241 b)moves it."(AP 241 b)

It is valid for the natural locomotion too, as It is valid for the natural locomotion too, as "the thing does not move itself, but it contains within itself the source"the thing does not move itself, but it contains within itself the source of motion - not of moving something or of causing motion, but ofof motion - not of moving something or of causing motion, but of suffering it." (AP 255b)suffering it." (AP 255b)

In the Aristotelian physics the interactions are by `contact'.In the Aristotelian physics the interactions are by `contact'."The fulfillment of the movable qua movable, the cause of the attribute"The fulfillment of the movable qua movable, the cause of the attribute being contact with what can move "(AP 202 a), being contact with what can move "(AP 202 a),

(it means, that the mover is also acted on, nevertheless the action-reaction(it means, that the mover is also acted on, nevertheless the action-reaction principle is only partial, as the first mover (the unmoved mover is not actedprinciple is only partial, as the first mover (the unmoved mover is not acted on, while the last moved does not act on.)on, while the last moved does not act on.)

The Aristotelian law for natural locomotion isThe Aristotelian law for natural locomotion is"A then will move through B in time , and through , which is thinner,"A then will move through B in time , and through , which is thinner, in time E (if the length of B is equal to ), in proportion to the density ofin time E (if the length of B is equal to ), in proportion to the density of the hindering body. " (AP 215 b)the hindering body. " (AP 215 b)

and " the bodies which have a greater impulse either of weight or ofand " the bodies which have a greater impulse either of weight or of lightness, if they lightness, if they are alike in other respects, move faster over an equalare alike in other respects, move faster over an equal space, and in the ratio which their magnitudes bear to each other." (APspace, and in the ratio which their magnitudes bear to each other." (AP

216 a)216 a)

What is the force here? What is the force here? The Aristotelian concept of force is not mechanical. As Jammer The Aristotelian concept of force is not mechanical. As Jammer 1515 points out points out there are two kinds of force in Aristotle's work:"...the Platonic conception ofthere are two kinds of force in Aristotle's work:"...the Platonic conception of force inherent in matter, which he (Aristotle) calls nature (physis), and forceforce inherent in matter, which he (Aristotle) calls nature (physis), and force as an emanation from substance, the force of push and pull, causing theas an emanation from substance, the force of push and pull, causing the motion in a second object, and not in itself." motion in a second object, and not in itself." Mary Hesse Mary Hesse 1616 asks the following question: What does this force essentially asks the following question: What does this force essentially belong to? To the body or to its natural place? Is it the `wish' of the body tobelong to? To the body or to its natural place? Is it the `wish' of the body to come to rest in its natural position? Or is it a kind of attraction exercised bycome to rest in its natural position? Or is it a kind of attraction exercised by the natural position on the moving body? the natural position on the moving body?

One way to solve this dilemma is to consider the body and the environmentOne way to solve this dilemma is to consider the body and the environment which includes its natural position a single system.which includes its natural position a single system.When bodies have come to rest in their natural position the system can beWhen bodies have come to rest in their natural position the system can be said to be in a state of equilibrium. A moving thing embodies the passivesaid to be in a state of equilibrium. A moving thing embodies the passive principle of motion in so far as it undergoes movement only as a result of itsprinciple of motion in so far as it undergoes movement only as a result of its lightness or heaviness. That is to say, it is `spurred' to action by its relationlightness or heaviness. That is to say, it is `spurred' to action by its relation to its environment, namely that it is not in its natural position. In this way theto its environment, namely that it is not in its natural position. In this way the force or `nature' inherent in the matter can be said to have a twofoldforce or `nature' inherent in the matter can be said to have a twofold character. character. On the one hand, it is an internal characteristic of the body, i.e. its lightnessOn the one hand, it is an internal characteristic of the body, i.e. its lightness or heaviness, on the other hand, it belongs to the natural position. Thisor heaviness, on the other hand, it belongs to the natural position. This double faced force strives to return the body to its natural position, anddouble faced force strives to return the body to its natural position, and thereby to restore order or equilibrium.thereby to restore order or equilibrium.

The Aristotelian force concept is similar to the generalized force ofThe Aristotelian force concept is similar to the generalized force of thermodynamics, caused by the inhomogeneities, i.e. by the deviation fromthermodynamics, caused by the inhomogeneities, i.e. by the deviation from the equilibrium state. The thermodynamic generalized force is defined as thethe equilibrium state. The thermodynamic generalized force is defined as the difference between the actual and the equilibrium values of intensivedifference between the actual and the equilibrium values of intensive parameters. The Aristotelian force is proportional to the difference betweenparameters. The Aristotelian force is proportional to the difference between the heaviness (lightness) belonging to the place, and that of the body. Thethe heaviness (lightness) belonging to the place, and that of the body. The effect of these forces is the continuous approach of the system to itseffect of these forces is the continuous approach of the system to its equilibrium state. With this interpretation the velocity has to be interpretedequilibrium state. With this interpretation the velocity has to be interpreted as the change of magnitude, i.e. the flux. With this thermodynamicas the change of magnitude, i.e. the flux. With this thermodynamic interpretation the laws of Natural Movement yield a concise system, which isinterpretation the laws of Natural Movement yield a concise system, which is summarized in Table III.summarized in Table III.

Table IIITable III

Aristotle's Concepts Aristotle's Concepts Their Thermodynamic Their Thermodynamic InterpretationInterpretation

Moving body and its Moving body and its environment environment

Natural locomotion Natural locomotion

Velocity of moving body (v) Velocity of moving body (v)

Natural positionNatural position

Moving toward natural position Moving toward natural position

Moving force (A) Moving force (A) (difference of heaviness or (difference of heaviness or lightness of the body and that of lightness of the body and that of the environment) the environment)

Resistance yielded by the Resistance yielded by the `environment' (B) `environment' (B)

Dynamic relation v ~ A/BDynamic relation v ~ A/B Unnatural forces can assist or Unnatural forces can assist or hinder natural movement hinder natural movement

Thermodynamic System Thermodynamic System

Transport process Transport process

Flow of extensive quantity (j) Flow of extensive quantity (j)

State of Equilibrium State of Equilibrium

Process aimed at counterbalan-Process aimed at counterbalan-cing inhomogeneous distributioncing inhomogeneous distribution

Driving force Driving force (Gradient of intensive (Gradient of intensive parameters of state) (X) parameters of state) (X)

Specific resistance (R) Specific resistance (R)

Dynamic formula j ~ X/RDynamic formula j ~ X/R

The processes of thermodynamicThe processes of thermodynamic system can be influenced by system can be influenced by external constraints, forces external constraints, forces

The constrained motion, too, can be understand in terms ofThe constrained motion, too, can be understand in terms of thermodynamics. The famous Aristotelian description is, as follows:thermodynamics. The famous Aristotelian description is, as follows:

"If, then, A the movent have moved B a distance in a time , then in"If, then, A the movent have moved B a distance in a time , then in the same time the same force A will move 1/2 B twice the distance ,the same time the same force A will move 1/2 B twice the distance , and in 1/2 it will move 1/2 B the whole distance : for thus the rules ofand in 1/2 it will move 1/2 B the whole distance : for thus the rules of proportion will be observed. Again if a given force move a given weightproportion will be observed. Again if a given force move a given weight a certain distance in a certain time and the distance in half the time,a certain distance in a certain time and the distance in half the time, half the motive power will move half the weight the same distance inhalf the motive power will move half the weight the same distance in the same time." (AP 250 a)the same time." (AP 250 a)

Nevertheless Aristotle is aware of nonlinearity, as he stated:Nevertheless Aristotle is aware of nonlinearity, as he stated:" ..does not follow that, if a given motive power causes a certain" ..does not follow that, if a given motive power causes a certain amount of motion, half the power will cause motion either of anyamount of motion, half the power will cause motion either of any particular amount or in any length of time: otherwise one man mightparticular amount or in any length of time: otherwise one man might

move a ship." (AP 250 a) move a ship." (AP 250 a) The above dynamic law is not only for locomotion, but for alteration and ofThe above dynamic law is not only for locomotion, but for alteration and of increase also, as Aristotle stated:increase also, as Aristotle stated:

"Then does this hold good of alteration and of increase also? Surely it"Then does this hold good of alteration and of increase also? Surely it does for in any given case we have a definite thing that cause increasedoes for in any given case we have a definite thing that cause increase and a definite thing that suffers increase, and the one causes and theand a definite thing that suffers increase, and the one causes and the other suffers a certain amount if increase in a certain amount of time.other suffers a certain amount if increase in a certain amount of time. Similarly we have a definite thing that causes alteration and a definiteSimilarly we have a definite thing that causes alteration and a definite thing that undergoes alteration and, a certain amount, or ratherthing that undergoes alteration and, a certain amount, or rather degree, of alteration is completed in a certain amount of time: thus indegree, of alteration is completed in a certain amount of time: thus in twice as much time twice as much alteration will be completed andtwice as much time twice as much alteration will be completed and conversely twice as much alteration will occupy twice as much time:conversely twice as much alteration will occupy twice as much time: and the alteration of half of its object will occupy half as much timeand the alteration of half of its object will occupy half as much time and in half as much time half of the object will be altered: or again inand in half as much time half of the object will be altered: or again in the same amount of time it will be altered twice as much." (AP 250 a-b)the same amount of time it will be altered twice as much." (AP 250 a-b)

Interpretations of the basic elements of Constrained Locomotion areInterpretations of the basic elements of Constrained Locomotion are contained in Table IV.contained in Table IV.

Table IV.Table IV.

The Four The Four Factor of Factor of movementmovement

AristotleAristotle Standard Standard Mechanical Mechanical InterpretatiInterpretation on

Aidun's Aidun's Mechanical Mechanical InterpretatiInterpretation on 1717

ThermodynaThermodyna-mic inter--mic inter-pretation pretation

AA

BB

CC

DD

Mover Mover

moved moved thing thing

Change of Change of magnitude magnitude

time time intervalinterval

force force

weight or weight or mass mass

displacemedisplacement nt

time time interval interval

power power

frictional frictional resistance resistance

displacemedisplacement nt

time time intervalinterval

driving force driving force

specific specific resistance resistance

change of change of extensive extensive quantity quantity

time time intervalinterval

The characteristics of the dynamics of Aristotelian constrained movements,The characteristics of the dynamics of Aristotelian constrained movements, are summarized in Table V, besides that of Newtonian Mechanics andare summarized in Table V, besides that of Newtonian Mechanics and thermodynamics. The comparison reflects the deep similarity of Aristotelianthermodynamics. The comparison reflects the deep similarity of Aristotelian dynamics and thermodynamics.dynamics and thermodynamics.

Table VTable V

Aristotelian Aristotelian (Peripatetic (Peripatetic Dynamics Dynamics 22

Newtonian Newtonian (Mechanical) (Mechanical) Dynamics Dynamics 77

ThermodynamicsThermodynamics

to sustain movementto sustain movement an acting force is an acting force is needed needed

V FV F

if F = O then v = 0 if F = O then v = 0

the movement: the movement: process process

acting force is acting force is needed to change needed to change the movementthe movement

d v/dt Fd v/dt F

if F = 0 then v = if F = 0 then v = cons.cons.

the movement: statethe movement: state

to sustain movementto sustain movement driving force is driving force is needed needed

j X j X

if F = 0 then j = 0 if F = 0 then j = 0

the movement: the movement: process process

3. THE ARISTOTELIAN WORLD VIEW3. THE ARISTOTELIAN WORLD VIEW

The Aristotelian physics is not physics in the Newtonian sense. It is a theoryThe Aristotelian physics is not physics in the Newtonian sense. It is a theory of nature, "in dealing with Aristotle, one has to try the best one can to forgetof nature, "in dealing with Aristotle, one has to try the best one can to forget that ever has been physics at al" was Woodbridge's suggestionthat ever has been physics at al" was Woodbridge's suggestion1818 or to read or to read as a general phenomenology, as an ancient thermodynamics (ouras a general phenomenology, as an ancient thermodynamics (our suggestion).suggestion).

Aristotle's Physical picture distinguishes between celestial and terrestrialAristotle's Physical picture distinguishes between celestial and terrestrial areas of activity. The main difference is the time behavior. The celestialareas of activity. The main difference is the time behavior. The celestial world is `perfectly' cyclic (i.e reversible), while the sublunar world is notworld is `perfectly' cyclic (i.e reversible), while the sublunar world is not cyclic (there are irreversible processes). cyclic (there are irreversible processes).

In the finite celestial world the laws of movement and the nature of theIn the finite celestial world the laws of movement and the nature of the constituent element differ from those in the sublunar world. Celestial bodiesconstituent element differ from those in the sublunar world. Celestial bodies are formed of a fifth element, ether (the later quintessence); and ether isare formed of a fifth element, ether (the later quintessence); and ether is unchanging and eternal so far as its qualitative nature is concerned. Thisunchanging and eternal so far as its qualitative nature is concerned. This celestial fifth element possesses only the tendency for uniform, continuous,celestial fifth element possesses only the tendency for uniform, continuous, circular movement, and the conclusion is circular movement, and the conclusion is

"the eternity of circular motion, i.e. the eternity of the revolution of the"the eternity of circular motion, i.e. the eternity of the revolution of the heavens (a fact which approved itself on other and independentheavens (a fact which approved itself on other and independent evidence)." (ADEG 338b)evidence)." (ADEG 338b)

The fundamental manifestations of matter and form in the terrestrial worldThe fundamental manifestations of matter and form in the terrestrial world

are the existence of four basic elementsare the existence of four basic elements--earth, water, air and fireearth, water, air and fire--eacheach having a distinctive pair of qualities. Earth is cold and dry water, cold andhaving a distinctive pair of qualities. Earth is cold and dry water, cold and wet; air, hot and wet; fire, hot and dry. These elements tend to arrangewet; air, hot and wet; fire, hot and dry. These elements tend to arrange themselves concentrically about the center of the world: the earth is athemselves concentrically about the center of the world: the earth is a sphere at the center, and the water, air, and fire are successive shells aboutsphere at the center, and the water, air, and fire are successive shells about the core of the earth. This tendency is realized as the `natural movement',the core of the earth. This tendency is realized as the `natural movement', which is unidirectional (irreversible).which is unidirectional (irreversible).

There is a close relation with thermodynamics, everything goes to its naturalThere is a close relation with thermodynamics, everything goes to its natural 11 . M. Delbrück, How Aristotle Discovered DNA, in: Physics and Our World: A Symposium in . M. Delbrück, How Aristotle Discovered DNA, in: Physics and Our World: A Symposium in

Honor of Victor F. Weisskopf, ed. K. Huang, Am. Inst. of Phys., N.Y., 1976, p.123-130.Honor of Victor F. Weisskopf, ed. K. Huang, Am. Inst. of Phys., N.Y., 1976, p.123-130.22 . K. Simonyi: Cultural History of Physics, Budapest, Gondolat, 1978 (in Hungarian) . K. Simonyi: Cultural History of Physics, Budapest, Gondolat, 1978 (in Hungarian)33 . Aristotle: Physics, with an English translation by P.H. Wicksteed and F.M.Cornford, vols. . Aristotle: Physics, with an English translation by P.H. Wicksteed and F.M.Cornford, vols.

II--II., Cambridge, Mass. Harvard Univ. Press and London, Heinemann, 1957 (in the II., Cambridge, Mass. Harvard Univ. Press and London, Heinemann, 1957 (in the following AP)following AP)

44 . Aristotle, Meteorologica, trans. E.W. Webster, Oxford at the Clarendon Press, 1907 (in the . Aristotle, Meteorologica, trans. E.W. Webster, Oxford at the Clarendon Press, 1907 (in the following: AM)following: AM)

55 . Aristotle, De generatione et corruptione, translated by H.H. Joachim, under the editorship . Aristotle, De generatione et corruptione, translated by H.H. Joachim, under the editorship of of W.D. Ross, Oxford at the Clarendon Press.1953. (in the following (ADEG)W.D. Ross, Oxford at the Clarendon Press.1953. (in the following (ADEG)66 . Aristotle, De Caelo, translated by J.L. Stocks, Oxford at the Clarendon Press, 1922. (in the . Aristotle, De Caelo, translated by J.L. Stocks, Oxford at the Clarendon Press, 1922. (in the

following ADC)following ADC)77 . K. Martinas, L.Ropolyi: On the Hidden Aristotelian Thermodynamics, Doxa, . K. Martinas, L.Ropolyi: On the Hidden Aristotelian Thermodynamics, Doxa, 99,113-128. ,113-128. 1987.1987. K. Martinas, L.Ropolyi: Aristotelian and Modern Physics, International Studies in the K. Martinas, L.Ropolyi: Aristotelian and Modern Physics, International Studies in the

Philosophy of Science, Philosophy of Science, 2, 2, 1-9, 1987.1-9, 1987.88 . P. Duhem: The evolution of mechanics, p. 188.,trans. Michael Cole, Sijthoff&Noordhoff, . P. Duhem: The evolution of mechanics, p. 188.,trans. Michael Cole, Sijthoff&Noordhoff,

Alphen aan den Rijn, The Netherlands, Germantown, Maryland, USA, 1980.Alphen aan den Rijn, The Netherlands, Germantown, Maryland, USA, 1980.99 . L. Tisza, Generalized Thermodynamics, Anns. of Physics, 1961. . L. Tisza, Generalized Thermodynamics, Anns. of Physics, 1961.1010

The concept of irreversibility has also several meaning in the literature, here we use the The concept of irreversibility has also several meaning in the literature, here we use the thermodynamic meaning, i.e. continuous approach to a final (equilibrium) state. If we deal thermodynamic meaning, i.e. continuous approach to a final (equilibrium) state. If we deal with the greek thinkers, it is vital to make the clear distinction of the different types of time with the greek thinkers, it is vital to make the clear distinction of the different types of time dependence:dependence: - reversible process is which can be reversed, i.e. the process can go through the same - reversible process is which can be reversed, i.e. the process can go through the same states backwards and forwards. states backwards and forwards. The processes which can not reversed are of two types:The processes which can not reversed are of two types: - irrevocable processes: if a state occurs it never occurs again, - irrevocable processes: if a state occurs it never occurs again, - irreversible process, which can not be reversed, nevertheless changing the external - irreversible process, which can not be reversed, nevertheless changing the external conditions (effects), one can go back from the final state to the same initial state.conditions (effects), one can go back from the final state to the same initial state.1111 Robert Locqueneux, Bernard Maitte, Bernard Pourprix, Les status epistemilogiques des Robert Locqueneux, Bernard Maitte, Bernard Pourprix, Les status epistemilogiques des

position, and without external effects (constrained movement) it remainsposition, and without external effects (constrained movement) it remains there, i.e. it is logically the same, as the equilibrium state concept ofthere, i.e. it is logically the same, as the equilibrium state concept of thermodynamics. The elements tends to seek a static arrangement in theirthermodynamics. The elements tends to seek a static arrangement in their natural place, it is equivalent to the heat death problem. As the Second Lawnatural place, it is equivalent to the heat death problem. As the Second Law of thermodynamics sates that a closed system tends to the equilibrium state,of thermodynamics sates that a closed system tends to the equilibrium state, being characterized by the absence of motion. This would happen in thebeing characterized by the absence of motion. This would happen in the Aristotelian Universe, if everything could occupy its natural position. AndAristotelian Universe, if everything could occupy its natural position. And really, Aristotle recognizes the consequence, if this would be the only effectreally, Aristotle recognizes the consequence, if this would be the only effect in the sublunar world, then after a while, everything would occupy its naturalin the sublunar world, then after a while, everything would occupy its natural position, so there would be no movement. (No natural movement, so noposition, so there would be no movement. (No natural movement, so no constrained movement too). Aristotle gives a the solution (at first in a veryconstrained movement too). Aristotle gives a the solution (at first in a very strange form). The four basic elements (fire, air, water, and earth) can bestrange form). The four basic elements (fire, air, water, and earth) can be transformed to each other. transformed to each other.

"Fire, air, water, earth, we assert, originate from one another, and each"Fire, air, water, earth, we assert, originate from one another, and each of them exists potentially in each, as all things do that can be resolvedof them exists potentially in each, as all things do that can be resolved into common and ultimate substrate." (AM 339 b)into common and ultimate substrate." (AM 339 b)

These transformations are caused by the movement. These transformations are caused by the movement. "there is one physical element which makes up the system of the"there is one physical element which makes up the system of the bodies that move in a circle, and besides this four bodies owing theirbodies that move in a circle, and besides this four bodies owing their existence to the four bodies are fire, air, water, earth. The whole worldexistence to the four bodies are fire, air, water, earth. The whole world surrounding the earth, then, the affections of which are our subject, issurrounding the earth, then, the affections of which are our subject, is made up of these bodies. This world necessarily has a certainmade up of these bodies. This world necessarily has a certain continuity with the upper motions: consequently all its power and ordercontinuity with the upper motions: consequently all its power and order is derived from them." (AM 339 a)is derived from them." (AM 339 a)

The source of movement for the sublunar world is the heat of Sun. (As theThe source of movement for the sublunar world is the heat of Sun. (As the height of Sun changes, there is a modification for the transformation of waterheight of Sun changes, there is a modification for the transformation of water to air or the transformation of water to air; this is the cause of the rains. to air or the transformation of water to air; this is the cause of the rains.

modeles de la theorie des gaz dans le oeuvres de Maxwell et Boltzmann, modeles de la theorie des gaz dans le oeuvres de Maxwell et Boltzmann, Fundamenta Fundamenta Scientiae, 4, 29-54, 1983.Scientiae, 4, 29-54, 1983.1212 W. J. Macquorn Rankine, Phil. Mag. W. J. Macquorn Rankine, Phil. Mag. 44 2828 404 (1864) 404 (1864)1313 M. Monleon-Pradas, The Physics of Quality, the present volume M. Monleon-Pradas, The Physics of Quality, the present volume1414 Frederick J.E. Woodbridge, Aristotle's Vision of Nature, Columbia University Press, N.Y. Frederick J.E. Woodbridge, Aristotle's Vision of Nature, Columbia University Press, N.Y.

London, 1965. p.156.London, 1965. p.156.1515 M. Jammer, Concepts of Force, Harvard Univ. Press, Cambridge, 1957, pp.35. M. Jammer, Concepts of Force, Harvard Univ. Press, Cambridge, 1957, pp.35.1616 Mary B. Hesse, Forces and Fields, Nelson and Sons, London 1961, p. 66. Mary B. Hesse, Forces and Fields, Nelson and Sons, London 1961, p. 66.1717 J. Aidun, Aristotelian Force as Newtonian Power, Phil. Science, 49, 1982, 228. J. Aidun, Aristotelian Force as Newtonian Power, Phil. Science, 49, 1982, 228.1818

op. cit. 13. p.49op. cit. 13. p.49

"For a motion that is to have this effect must be rapid and near, and"For a motion that is to have this effect must be rapid and near, and that of the stars is rapid but distant, while that of the moon is near butthat of the stars is rapid but distant, while that of the moon is near but slow, whereas the suns motion combines both conditions in a sufficientslow, whereas the suns motion combines both conditions in a sufficient degree." (AM 341 a)degree." (AM 341 a)

The detailed mechanism is:The detailed mechanism is:"For the sun as it approaches or recedes, obviously causes dissipation"For the sun as it approaches or recedes, obviously causes dissipation and condensation and so gives rise to generation and destruction. Nowand condensation and so gives rise to generation and destruction. Now the earth remains but the moisture surrounding it is made tothe earth remains but the moisture surrounding it is made to evaporate by the suns rays and the other heat from above, and rises.evaporate by the suns rays and the other heat from above, and rises. vapor cools because its heat is gone and because the place is cold, andvapor cools because its heat is gone and because the place is cold, and condenses again and turns from air into water. And after the water hascondenses again and turns from air into water. And after the water has formed it falls down again to the earth." (AM 346 b)formed it falls down again to the earth." (AM 346 b)

The above mechanism explains the cyclic character of meteorologicalThe above mechanism explains the cyclic character of meteorological effects.effects.

"So we get a circular process that follows the course of the sun." (AM"So we get a circular process that follows the course of the sun." (AM 347 a)347 a)

The `heat death' problem and solution in Aristotelian approach:The `heat death' problem and solution in Aristotelian approach:"These considerations serve at the same time to explain what is to"These considerations serve at the same time to explain what is to some people a baffling problemsome people a baffling problem--viz. why the simple bodies, since eachviz. why the simple bodies, since each of them is travelling towards its own place, have not becomeof them is travelling towards its own place, have not become dissevered from one another in the infinite lapse of time. The reason isdissevered from one another in the infinite lapse of time. The reason is their reciprocal transformation. For, had each of them persisted in itstheir reciprocal transformation. For, had each of them persisted in its own place instead of being transformed by its neighbor, they wouldown place instead of being transformed by its neighbor, they would have got dissevered long ago. They are transformed, none of them ishave got dissevered long ago. They are transformed, none of them is able to persist in any place allotted to it by the Order". (ADEG 337 a)able to persist in any place allotted to it by the Order". (ADEG 337 a)

And this reciprocal transformation is caused by the following chain;And this reciprocal transformation is caused by the following chain; Unmoved mover - motion of eternal bodies (spheres) - heat of Sun -Unmoved mover - motion of eternal bodies (spheres) - heat of Sun - transformation of elements - natural movements - constrained movements.transformation of elements - natural movements - constrained movements.

This chain shows that the unmoved mover mixes the universe. The UnmovedThis chain shows that the unmoved mover mixes the universe. The Unmoved mover continuously kicks out the sublunar world from the equilibrium state.mover continuously kicks out the sublunar world from the equilibrium state. (He/she kicks out from the natural position the elements, transforming the(He/she kicks out from the natural position the elements, transforming the elements from one state to the other state). This role can be called, as anelements from one state to the other state). This role can be called, as an Entropic God.Entropic God.It is interesting to note, that from logical aspects the Unmoved mover seemsIt is interesting to note, that from logical aspects the Unmoved mover seems to be superfluous, as the heaven's motion is eternal, so it would beto be superfluous, as the heaven's motion is eternal, so it would be acceptable, that this eternal movement causes the motion in the sublunaracceptable, that this eternal movement causes the motion in the sublunar world, nevertheless Aristotle's deep physical insight forbad this solution, as ifworld, nevertheless Aristotle's deep physical insight forbad this solution, as if something can be a mover, then it can move, and then its moment can stop,something can be a mover, then it can move, and then its moment can stop, so the action-reaction principle makes necessary to introduce the Unmovedso the action-reaction principle makes necessary to introduce the Unmoved mover, the Entropic God, who's characteristics are summarized, as:mover, the Entropic God, who's characteristics are summarized, as: "if the movement is to be continuous, what initiates it must be single,"if the movement is to be continuous, what initiates it must be single,

unmoved, ungenerated, and incapable of alteration since time isunmoved, ungenerated, and incapable of alteration since time is continuous" (AP 190 a) continuous" (AP 190 a)

Aristotle states too, that in the sublunar world instead of the cyclic character,Aristotle states too, that in the sublunar world instead of the cyclic character, the rectilinear features are dominant, he gave the classification of thethe rectilinear features are dominant, he gave the classification of the changes as:changes as:

"Those things, whose substance "Those things, whose substance -- that which is undergoing the that which is undergoing the processprocess-- is imperishable, will be numerically, as well as specifically the is imperishable, will be numerically, as well as specifically the same in their recurrence ... Those thing on the other hand, whosesame in their recurrence ... Those thing on the other hand, whose substance is perishable (not imperishable) must return uponsubstance is perishable (not imperishable) must return upon themselves in the sense that what recurs, though specifically thethemselves in the sense that what recurs, though specifically the same, is not the same numerically. That is why, when Watersame, is not the same numerically. That is why, when Water comescomes--toto--be from Air and Air from Water the Air is the samebe from Air and Air from Water the Air is the same specifically, not numerically" (ADEG 338 b)specifically, not numerically" (ADEG 338 b)

After he puts the question:After he puts the question:"Then why do some things manifestly come"Then why do some things manifestly come--toto--be in this cyclicalbe in this cyclical fashion (as. e.g., showers and air), so that it must rain if there is to befashion (as. e.g., showers and air), so that it must rain if there is to be a cloud and, conversely, there must be a cloud if it is to rain), whilea cloud and, conversely, there must be a cloud if it is to rain), while men and animals do not return upon themselves so that the samemen and animals do not return upon themselves so that the same individual comes toindividual comes to--bebe--second time (for though your comingsecond time (for though your coming--toto--bebe presupposes your fathers, his comingpresupposes your fathers, his coming--toto--be does not presupposebe does not presuppose yours)? Why, on the contrary, does this comingyours)? Why, on the contrary, does this coming--toto--be seem tobe seem to constitute a rectilinear sequence? " (ADEG 338 b)constitute a rectilinear sequence? " (ADEG 338 b)

The solution of the paradox arising from the cyclic character of the celestialThe solution of the paradox arising from the cyclic character of the celestial movements and the chaotic feature of sublunar word:movements and the chaotic feature of sublunar word:

"We have assumed and have proved, that coming"We have assumed and have proved, that coming--toto--be andbe and passingpassing--away happen to things continuously; and we assert thataway happen to things continuously; and we assert that motion causes comingmotion causes coming--toto--be. The movements must, on the contrary,be. The movements must, on the contrary, be more than one, and they must be contrasted with one anotherbe more than one, and they must be contrasted with one another either by the sense of their motion or by its irregularity: for contraryeither by the sense of their motion or by its irregularity: for contrary effects demand contraries as their causes. This explains why it is noteffects demand contraries as their causes. This explains why it is not the primary motion that causes comingthe primary motion that causes coming--toto--be and passingbe and passing--away, butaway, but the motion along the inclined circle. For if comingthe motion along the inclined circle. For if coming--toto--be andbe and passingpassing--away are always to be continuous."(ADEG 339 b)away are always to be continuous."(ADEG 339 b)

4. Further Thermal elements4. Further Thermal elements

Most of the basic thermodynamic concepts such as temperature, equilibriumMost of the basic thermodynamic concepts such as temperature, equilibrium inhomogeneity, irreversibility, driving force, thermal interaction inhomogeneity, irreversibility, driving force, thermal interaction 1919,, selfself--organization can be found in his dynamical views. organization can be found in his dynamical views.

The hot and cold are the active contraries, they role is as follows:The hot and cold are the active contraries, they role is as follows:" `Hot' is that which `associates' things of the same kind (...Fires's" `Hot' is that which `associates' things of the same kind (...Fires's effect is to eliminate what is foreign), while `cold' is that which bringseffect is to eliminate what is foreign), while `cold' is that which brings together, i.e. `associates', homogeneous and heterogeneous thingstogether, i.e. `associates', homogeneous and heterogeneous things alike" (ADEG 329alike" (ADEG 329bb (25-30) (25-30)

We have hinted at his recognition of the content of the Second Law ofWe have hinted at his recognition of the content of the Second Law of thermodynamics, and it is clear that he was familiar with the essence of thethermodynamics, and it is clear that he was familiar with the essence of the First one, too. Evidence for this is the knowledge of the fact: heat could beFirst one, too. Evidence for this is the knowledge of the fact: heat could be produced by friction. produced by friction. Interesting is the definition of the concept of heat:Interesting is the definition of the concept of heat:

"As for the heat derived from the sun, the right place for a special and"As for the heat derived from the sun, the right place for a special and scientific account of it is in the treatise about sense, since heat is anscientific account of it is in the treatise about sense, since heat is an affection of sense, but we may now explain how it can be produced byaffection of sense, but we may now explain how it can be produced by the heavenly bodies which are not themselves hot." (AM 340 b)the heavenly bodies which are not themselves hot." (AM 340 b)

In the De Caelo he argues, that the stars are not composed of fire:In the De Caelo he argues, that the stars are not composed of fire:"The warmth and light which proceed from them (stars) are caused by"The warmth and light which proceed from them (stars) are caused by the friction set up in the air by their motion. Movement tends to createthe friction set up in the air by their motion. Movement tends to create fire in wood, stone and iron and with even more reason should havefire in wood, stone and iron and with even more reason should have that effect on air, a substance which is closer to fire than these." (ADCthat effect on air, a substance which is closer to fire than these." (ADC 289 a 19-24)289 a 19-24)

An example is that of missiles, which as they move are themselves fired soAn example is that of missiles, which as they move are themselves fired so strongly that leaden balls are melted; and if they are fired the surroundingstrongly that leaden balls are melted; and if they are fired the surrounding air must be similarly effected. air must be similarly effected.

"Now while the missiles are heated by reason of their motion in air,"Now while the missiles are heated by reason of their motion in air, which is turned into fire by the agitation produced by their movement,which is turned into fire by the agitation produced by their movement, the upper bodies are carried on a moving sphere, so that, though theythe upper bodies are carried on a moving sphere, so that, though they are not themselves fired, yet the air underneath the sphere of theare not themselves fired, yet the air underneath the sphere of the revolving body is necessarily heated by its motion, and particularly inrevolving body is necessarily heated by its motion, and particularly in that part where the sun is attached to it." (ADC 289 a 19-33)that part where the sun is attached to it." (ADC 289 a 19-33)

The primitive (antique) concept of heat capacity is also present.The primitive (antique) concept of heat capacity is also present.Aristotle investigates the problem, how it is possible to compare differentAristotle investigates the problem, how it is possible to compare different things, and he writes:things, and he writes:

"All the `comparables' must possess an identical something, whereby"All the `comparables' must possess an identical something, whereby they are measured. As for instance, lets investigate the case of Waterthey are measured. As for instance, lets investigate the case of Water and Air"..."they are not comparable in their amount in the sense thatand Air"..."they are not comparable in their amount in the sense that soso--much of the one yields somuch of the one yields so--much of the other but comparable inmuch of the other but comparable in power of action (power of action (a pint of water e.g., having a power of cooling equal toa pint of water e.g., having a power of cooling equal to that of ten pints of Airthat of ten pints of Air); even so, they are comparable in their amount,); even so, they are comparable in their amount,

1919

Aristotle, Metaphysics, by H. Fredennick, Cambridge, Mass., Harvard Univ. Press Aristotle, Metaphysics, by H. Fredennick, Cambridge, Mass., Harvard Univ. Press and and London, Heinemann, 1961. London, Heinemann, 1961.

though not qua amount but qua sothough not qua amount but qua so--much power. Thus it is manifestlymuch power. Thus it is manifestly absurd that the simple bodies though they are not transformable, areabsurd that the simple bodies though they are not transformable, are comparable not merely as corresponding but by a measure of theircomparable not merely as corresponding but by a measure of their powers; i.e. that sopowers; i.e. that so--much. Fire is comparable withmuch. Fire is comparable with manymany--timestimes--thatthat--amount of Air, as being equally or similarly hot. Foramount of Air, as being equally or similarly hot. For the same thing, if it be greater in amount, will, since it belongs to thethe same thing, if it be greater in amount, will, since it belongs to the same kind, have its ratio correspondingly increased." (ADEG 333 a 20-same kind, have its ratio correspondingly increased." (ADEG 333 a 20-30)30)

5. New results5. New results

As we mentioned in the introduction, we could find some aspects in AristotleAs we mentioned in the introduction, we could find some aspects in Aristotle which are not well discussed in the modern thermodynamics.which are not well discussed in the modern thermodynamics.First of all, the causality of Aristotle. The usual interpretation of it we citeFirst of all, the causality of Aristotle. The usual interpretation of it we cite form the excellent book of Clagettform the excellent book of Clagett2020: "When we examine more deeply the: "When we examine more deeply the principles of things we are struck by four types of causation principles of things we are struck by four types of causation -- one might say one might say by four `factors' that are involved in things that exist in the terrestrial world.by four `factors' that are involved in things that exist in the terrestrial world. The first is the `material' factor, the second is the `formal,' the third is theThe first is the `material' factor, the second is the `formal,' the third is the efficient, fourth is the final or purposeful cause. The four causes can beefficient, fourth is the final or purposeful cause. The four causes can be explained by analogy with something artificially produced. A bed is aa bedexplained by analogy with something artificially produced. A bed is aa bed because it is made of wood (the material cause), in a given shape (its formalbecause it is made of wood (the material cause), in a given shape (its formal cause), by a carpenter (its efficient cause,), for the purpose of providingcause), by a carpenter (its efficient cause,), for the purpose of providing slumber (final cause).slumber (final cause).

Table VII Table VII AristotleAristotle MechanicsMechanics thermodynamicsthermodynamicsmaterial causematerial cause extensive quantitiesextensive quantitiesformal causeformal cause constitutive constitutive

equationsequationsefficient causeefficient cause forceforce generalized force (or generalized force (or

inhomogeneities)inhomogeneities)final causefinal cause equilibriumequilibrium

This table shows that in the mechanic description only the efficient cause isThis table shows that in the mechanic description only the efficient cause is present, while all the four causes can be identified in a thermodynamicpresent, while all the four causes can be identified in a thermodynamic description. description. The other interesting subject appears in the description of a particularThe other interesting subject appears in the description of a particular change. Aristotle considers movement as a process in which potentialitieschange. Aristotle considers movement as a process in which potentialities 2020

M. Clagett, Greek Science in Antiquity, Abelard-Schuman, Inc., New York, 1955.M. Clagett, Greek Science in Antiquity, Abelard-Schuman, Inc., New York, 1955.

become actual. He describes each particular process of this kind in threebecome actual. He describes each particular process of this kind in three concepts: dynamis, energeia, and entelekheia. Dynamis means roughlyconcepts: dynamis, energeia, and entelekheia. Dynamis means roughly ability to change.ability to change.2121 Energeia stands for the working of this ability. Energeia stands for the working of this ability.2222

Entelekheia is best constured as realized ability.Entelekheia is best constured as realized ability.2323 Table VIII. gives the usual mechanic and the possible thermodynamicTable VIII. gives the usual mechanic and the possible thermodynamic interpretations of the Aristotelian concepts concerning a particular change.interpretations of the Aristotelian concepts concerning a particular change. The basic argument against the mechanical interpretation of energeia asThe basic argument against the mechanical interpretation of energeia as kinetic and potential energy follows from the fact, that the Aristoteliankinetic and potential energy follows from the fact, that the Aristotelian energeia characterizes the process, while the energy belonges to the state,energeia characterizes the process, while the energy belonges to the state, generally changing along the process.generally changing along the process.

Table VIII.Table VIII.Aristotle's Aristotle's ConceptsConcepts

Their Meaning Their Meaning MechanicMechanicInterpretationInterpretation

ThermodynamicThermodynamic InterpretationInterpretation

dynamis dynamis

energeiaenergeia

entelekheiaentelekheia

ability ability the potentialitythe potentiality of change of change

working of the working of the ability (the ability (the actualization ofactualization of change) change)

realized ability realized ability (change which (change which has been has been actualized)actualized)

force force (associated to (associated to constrained constrained movement) movement)

energy energy (potential and (potential and kinetic)kinetic)

driving force driving force (caused by (caused by inhomogeneity)inhomogeneity)

the process of the process of homogenization homogenization

equilibriumequilibrium(the immediate (the immediate state) as the state) as the actualized actualized homogenization.homogenization.

The fact that in each of Aristotle's analysis these concepts appear in dynamisThe fact that in each of Aristotle's analysis these concepts appear in dynamis -- energeia energeia -- entelekheia order can also be readily explained. entelekheia order can also be readily explained.

2121

op. cit.13. p. 32.op. cit.13. p. 32.2222

op. cit. 13. p. 34.op. cit. 13. p. 34.2323

op. cit. 13. pp. 126op. cit. 13. pp. 126--127127

It is the central idea of thermodynamics, that the natural processes has aIt is the central idea of thermodynamics, that the natural processes has a direction (toward the equilibrium state), and this order is reflected by thedirection (toward the equilibrium state), and this order is reflected by the Aristotelian order, nevertheless in thermodynamics we always talk about theAristotelian order, nevertheless in thermodynamics we always talk about the approach to the equilibrium state, nevertheless in reality the result ofapproach to the equilibrium state, nevertheless in reality the result of thermodynamic processes is an intermediate state (and very frequent it isthermodynamic processes is an intermediate state (and very frequent it is not the equilibrium). The Aristotelian entelekheia concept fits better to thisnot the equilibrium). The Aristotelian entelekheia concept fits better to this `intermediate' state, and it could help to weaken the misunderstanding, that`intermediate' state, and it could help to weaken the misunderstanding, that thermodynamics is able to describe only the equilibrium.thermodynamics is able to describe only the equilibrium.

AcknowledgementsAcknowledgements

The author would like to express her gratitude for the interesting discussionsThe author would like to express her gratitude for the interesting discussions to L. Ropolyi, M. Fehér.to L. Ropolyi, M. Fehér.She thanks for the Delbrück paper to Prof. L. Tisza, and to Prof. R.She thanks for the Delbrück paper to Prof. L. Tisza, and to Prof. R. Locqueneux for calling her attention to the relation of Duhem and Rankine toLocqueneux for calling her attention to the relation of Duhem and Rankine to Aristotle's physics, and for giving the references. Aristotle's physics, and for giving the references.

References:References: