Inductive Argument

• A person travels through a town for the first time. He sees 10 people, all of them children. The person then concludes that there are no adult residents in the town.

• Divorce is rampant in America. I heard that 50% of marriages end in divorce within three years. Conclusion: So I've decided not to marry you because the odds are against us.

Induction– admitting “wrongness”

Given the pattern below we can inductively reason that the next pattern will be?

Argument was not set up by any rules provided to us (deduction), but rather we observed trough our senses and made a predictable decision---conclusion

Induction• Gathering facts through observation (empirical)• Feel, see, touch…..

• Identify reasonable patterns• Associate like situation

• Move from individual observation to make general conclusions• Make broad assumption

• Type of logic used most by people, but the weakest• Allows us to use reason in life, with problems

We form theories about the world and observations strengthen or weaken those theories

Induction- Argument• The conclusion probably follows from the premises

given. Make the best choice. • Conclusion not true or false, but is better or worse• Inference (glue): • Offer more support for conclusion• Observation from five senses strengthen inferences• The inferences in NEVER 100%• We accept that we could be wrong• We are forced to make assumption (bad)

We are working off the confidence of true observation and reasonable probability

Induction- Conclusion• Parts to whole• Every cat I have met I didn’t like, I hate all cats

• Similar situation• I took a philosophy class five years ago and hated it. This is also

a philosophy class, I will hate this one as well.

• Predictions• Americans don’t support gun control, they will always be a

defendant of the second amendment.

• Cause and effect• All sugar treats cause child obesity

Conclusion has a direct relationship to the quality of evidence chosen to develop argument

Degrees of Probability:

99%±—Virtually Certain (gravity)90%±—Highly Probable (no two snowflakes

alike)70%±—Probable (for medicines to work)50%±—Possible (coin toss)30%±—Improbable (life on other planets?)10%±—Highly Improbable (that Jesus is in this

class)

Induction- Common Uses• All Sciences

• The first domino will fall• Whenever a domino falls, its next neighbor will also fall• So it is concluded that all of the dominoes will fall.

• Language and communication• Define words• Math as a language• Protocol to computer language/code (agree what www. means)• Get advice:• Vote (political ads)• What to purchase (web reviews)• Relationships (friend)

• Medical profession like gambling?• The problem of Socrates' certainty

Current Streak GB: W6 (2011–)

Longest Streak

GB: W10 (1994–1998)

Current Trend GB: Won 8 of last 10

All-Time Series GB: leads 92–88–6

Any different then the medical field?1. What are your symptoms?2. You provide data3. Here is the “diagnosis” on the information gathered4, This is not a necessary conclusion

Generalization• Move from specific (small) observation(s) to a

generalized (big) overall conclusion• Stereotype

• Make broad conclusion with information provided• Evidence based conclusion

• Less certain (sound) than deductive arguments• Assumption

Assume the possibility that you are wrong• Humans make mistakes• Thought something would happen, but didn’t• Just try and make a “reasonable decision”

Generalization-- Evaluation• What is percentage of probability? • How much evidence

• How was the probability achieved?• Type of evidence

• What was the control group?• Credibility of evidence

• Was it truly representative?• Larger group not included in evidence

• Other variables that can “poison” the probability?• Outside evidence that disproves conclusion

Generalization- three typesDrawing conclusion from a group based on characteristics found in a SAMPLE (test) group • Analogies (likes or similarities)• Drawing conclusion from similarities found in two events or

things• Coke is like Pepsi. If I like Coke, then I’ll like Pepsi

• Causal Arguments (why/who/what)• Try to find the reason for an event by finding the cause• What caused this disease?• Who caused this accident?• Testing or examination usually leads to the answer

• Polls (present feelings…predict future feeling)• Collect data on small (sample) group to defines the whole• Obamas approval = 42%• Obama disapproval = 52%• Total = 94%• Oct. 25th 2013

Gallup, “Daily results are based on telephone interviews with approximately 1,500 national adults; margin of error is ±3 percentage points.”

Analogies- MetaphorUnlike things are compared because they may have one/few thing(s) in common or alike.• Draw descriptive similarities to a thing, event or

situation.• Allows the writer/reader more freedom to compare

two somewhat unrelated things for dramatic effect.• The detective listened to her tales with a wooden face.• She was fairly certain that life was a fashion show.• The typical teenage boy’s room is a disaster area

Fallacy of Emotion• Usually used to increase emotion and/or attention• Watered down argument for the sake of

association/retention• People like stories

Causal Arguments• Cause and effect relationship• Know the effect (result)• Find out what brings about change or the

cause • Conclusion is that some one entity is effecting

another separate entity.• Cause (Premise) You didn’t study and you didn’t

come to class. Effect (Conclusion) You will not pass the test.• You know the conclusion upfront• Doesn’t account for random events or variables• The more times the EVENT happens the strong

case for the cause and effect relationship. (testing)

• Fallacy of False Cause• We wrongly apply OR overstate a certain cause to a

certain effect.

Controlled experiment• Scientific Method• Tries to limit variables• Divide experiment into two groups• Experimental group- allow the cause to enter the

experiment and see if the effect happens• Controlled group- do not allow cause to enter the

experiment and see what happens

• The experimental group should have the cause – effect relationship and the control group should not. • The more times the effect happens in this

relationship the stronger the inference is for the cause to be the reason why.

Four problems- Goal: avoid X factor or variable(s) not accounted for• A random to BIn 2001 people ate the most ice creamIn 2001 there were the most shark attacksObviously, ice cream causes shark attacks

• B causes ANot going to school causes gangsReally, the gangs cause not going to school

• A and B cause each otherThe bad economy caused the stock market to crashReally, the stock market crash and the bad economy caused each other

• A just one of multiple equal causes of BSmoking caused your heart attackReally, you smoked, drank tequila, didn’t exercise and had a bad family history

Evaluate Causal Arguments?• Is the cause effect relationship strong?

• False causes fallacy or over-generalizing?

• Is the causes up to date?

Evaluate this Causal ArgumentThe countries that spend the most on defense cause them to be the safest countries in the world• How strong is the relationship• Top three defense spending countries: USA $300

billion, Russia $44 billion and Japan $40 billion• What are the lowest three?

• False cause fallacy (ex: b causes a)• The safest countries are the most rich and CAN

spend more on defense, which in-turn makes them even more safe. (what is the cause: Defense, Safety or $$$)

• Up to date?• Pre or Post Cold War• Pre or Post Desert Storm• Pre or Post 9/11• Pre or Post Afghan/Iraq Wars

PollingTake a sampling of individual opinions and try to conclude something about general opinion of the whole. Generally- also claims to represent the whole of something

Absolutely Depends on REPRESENTATIVE sampleNo confirmation bias: Favoring outcome one way• Cherry picking: people, words and choices• Rhetoric: emotional questions • Loaded Question: ask two questions in one• Need Random: everyone has equal chance of being

selected• Not Weighted: written for one group• Limited choice: forces you to choose• Results: overextend to general

Fallacy of False Dilemma• Only allow for two Reponses, when there may be

multiple choices at your disposal.

“…59% of American favor allowing gay or lesbians couples to legally wed”

Evaluating Polls• Who conducted poll (bias)

• Is it a representative sample (cherry picking)

• Size of sample

• Questions asked

Evaluate this pollMitt Romney leads by nine percent in new QStarNews presidential poll. October 25, 2012 (1st site on Google)

• Who is QStarNews?• Some weird Website

• Who did they Ask?• Website poll

• How many people?• 2500 people• US pop (314 mil)• 000008%

• How did they ask• Who the heck knows?