Inductive Reasoning: The logic of Science

1. Inductive Reasoning: The logic of Science

2. Deductive vs Inductive Logic Deductive • You try to prove something is certainly true • Linked premises P1: All humans are mortal P2: Socrates is human C: So, Socrates is mortal Inductive • You try to prove that something is probably (most likely) true • Don’t necessarily have linked premises P1: Smith hates Jones P2: Jones was killed with Smith’s gun P3: Smith has no alibi C: Jones, most likely, killed Smith

3. Types of Inductive arguments • Enumerative Induction – I observe some sample of a population and make claims from that sample about the entire population. [beware of hasty generalization] • Argument from Analogy – X and Y are alike with respect to A. X also has B, so Y probably has B too. [beware of a faulty analogy] • Causal arguments – claiming that X caused Y; or, that there is a causal relationship between X and Y. You have to show that X is capable of causing Y, that X in fact interacted with Y, that Y did not cause X, and that something else did not cause them both. [beware of the causal fallacy (post hoc)]

4. Enumerative Induction P1: X Percent of the observed members of group A have Property P C: Therefore, X percent of all members of group A have Property P

5. Key terms for Enumerative induction Target population (group) – the whole collection of individuals in question Sample (members) – the observed members of the target group Relevant property (property in question) – the property we’re interested in For example: TP = All Swans; SM = Swans we have seen; RP = White feathers. All the Swans that we have seen have white feathers. So, most likely, all swans have white feathers.

6. Problems with Enumerative Inductions • Sample Size – If your sample is too small, your conclusion is hasty. • Representativeness – your sample must be like the target group by having (1) all the same relevant characteristics, and (2) having them in the same proportions that the target group does. If your sample is not representative, it is a Biased Sample

7. Analogical Induction P1: Thing A has properties P1, P2, P3, plus the property P4 P2: Thing B has properties P1, P2, P3 C: Therefore, thing B probably has Property P4

8. How do I know that an analogical induction is a good one? There are four criteria: • Relevant similarities • Relevant dissimilarities • The number of instances compared • Diversity among the cases Example P1: Mice have a mammalian circulatory system, are mammals, have typical mammalian biochemical reactions, tend to have cholesterol reduced by cholesterol drugs, and Drug Z works on them. P2: Humans have a a mammalian circulatory system, are mammals, have typical mammalian biochemical reactions, and tend to have cholesterol reduced by cholesterol drugs C: So, Drug Z should work on humans too

9. The problem of other minds The problem – I know that I have a mind, because I am directly aware of my own thoughts. But how do I know others have minds? I cannot know their thoughts!

10. Good analogical argument: That other people have minds P1: I show emotions, speak, seem to make choices, and I have a mind P2: Other people show emotions, speak, seem to make choices C: Therefore, other people probably have minds too Notice: The same argument is used to show that animals have feelings, and proposed as the way to know if robots could have minds

11. The Design Argument P1: All machines of exquisite complexity were made by intelligent beings for a purpose P2: The universe is very much like a exquisitely complex machine, in that it seems ordered and organized for a purpose. ___________________________ C: The Universe probably was made by an intelligent being, namely God.

12. David Hume’s Objections • It is not so clear that the universe is like a machine • Even if the universe has a designer we can’t say anything about what that designer is like, or even if there is only one, so why call it “God”?

13. The Watchmaker – William Paley 1902 P1: Something as a complex as a watch could not have come to be by accident. Someone had to have made that thing for a clear purpose. P2: Living organisms are even more complicated than watches (look how well they fit their environment!). C: So, living organisms must have been designed for a clear purpose too

14. Evolution by natural selection Charles Darwin

15. Casual Arguments • Two kinds: 1) X caused Y, and 2) there is a casual relationship between X and Y

16. Mill’s Methods • Agreement • Difference • Agreement and Difference • Correlation

17. The Case of Elmo’s Bar Bill went to Elmo’s bar ate cheese and drank the wine, and got sick later Emily went to Elmo’s bar, drank the wine and ate crackers and got sick later Tyrone went to Elmo’s bar drank the wine and ate grapes and got sick later Hector went to Elmo’s bar, drank beer, vodka, and wine and got sick later. Kim went to Elmo’s bar, just drank beer, and Kim did not get sick later

18. Correlation Causation We can never prove a causal relationship Why? Because all we ever experience is constant correlation – that in the past B always followed A. But… how can we know, that the future will resemble the past? ……… WE DON’T! David Hume 1711-1776

19. Casual Confusions • Misidentifying Relevant Factors • Mishandling Multiple Factors • Being Misled by Coincidence. • The Post Hoc or Causal Fallacy • Confusing Cause and Effect

20. Necessary & Sufficient Conditions Necessary – a condition, without which, the event cannot occur Sufficient- a condition that, if present, guarantees that the even occurs For Example: Killing a goldfish Sufficient condition: not feeding the fish for many days Necessary conditions: fish not receiving oxygen, fish not eating, does not swim. *Sometimes the sufficient condition is just all the necessary conditions combined

21. Abduction: Inference to the best explanation • P1: Phenomenon Q • P2: E Provides the best explanation of Q • C: Therefore, it is probable that E is true A B E

22. Near Death Experiences (NDEs) • 1. It’s really afterlife 2. It’s a illusion created by a dying (oxygen deprived) brain

23. Criteria of adequacy • Testability – Can I test the hypothesis? • Fruitfulness – Does this hypothesis give us novel predictions? • Scope – How much does the hypothesis explain? • Simplicity – How many assumptions does the hypothesis make? Ockham’s Razor – “things being equal, the simplest explanation is the best one.” • Conservatism – How well does the hypothesis fit with our best well established beliefs? The Sagan Principle – “Extraordinary claims demand extraordinary evidence.”

24. Copernicus and the Sun 1543 – Copernicus tells us that the Earth is a planet that goes around the sun • Simplicity 1610 – Galileo makes observations with a telescope that give evince Copernicus was right - Testability

25. Charles Darwin Born February 12, 1809 (same day and year as Lincoln) Sailed on the HMS Beagle 1831-1836 Published On The Origin of the Species 1859 Published The Descent of man 1871 Died April 19 1882, aged 73

26. Theory of Evolution by Natural Selection • Organisms reproduce and their reproductions differ a little bit from them (mutation) • Some mutations are advantageous in the environment an organism finds itself in, some are not • The organisms with an advantage pass on their traits, the one’s without an advantage die off • Eventually the changes are big enough that we have a brand new species • Given Billions of years, this process can account for all the diversity of life we see today

27. Evidence for evolution Darwin’s Evidence • The Fossil Record • Geographic location of various species • Comparative Anatomy • Artificial Selection Post Darwin Evidence 5) Genes 6) DNA 7) Treating Viruses 8) Embryology

28. Biblical Creationism vs Evolution through natural selection • Creation • God created the world in “7 days” in the order the Bible describes it • God created Adam and Eve in their adult state from no prior pre-human state. • Many generations later God destroyed most life on earth in a great flood • Evolution • The Earth is Billions years old. • Life is Billions of years old. • All life on earth originated with a single common ancestor, some one celled creature. • All life came to be in its present forms by a mechanical process of evolution by means of random mutation and natural selection

29. The TEST formula • Step 1: State the Theory and check for consistency • Step 2: Assess the Evidence for the theory • Step 3: Scrutinize alternative theories • Step 4: Test the theories with the criteria of adequacy

30. What is science? Well …. It’s not technology; that’s an application of science. It’s not Scientism = science is the only way to know things, the only subject that really matters, the only way to any truth. So …. What is it???? Science – a set of empirically testable/observable claims about the physical world, it’s laws, properties, and behavior.

31. Scientific Method • Identify the problem or pose a question • Devise a hypothesis to explain the event or phenomenon • Derive a test implication or prediction from the hypothesis • Perform the test • (Provisionally) Accept or reject the hypothesis

32. Scientific Terms Hypothesis = an explanation that you can check by testing or observation or both Theory = a hypothesis that has passed the test according to a large majority of scientists. Scientific Truth = You can only prove something is true beyond “reasonable doubt,” but never with absolute certainty.

33. Science and the Paranormal/Supernatural Definitions: • Supernatural – entities or processes or powers that are “beyond” our natural world. For example, angels, ghosts, demons, fairies • Paranormal – Events and/or beings that are “out of the ordinary” realm of our experience, but are not necessarily supernatural; rather, they are, supposedly, the “as-yet-unconfirmed-by-science” but still natural events and/or beings. For example, Bigfoot, Alien Abduction, etc.

34. Science vs. Pseudo-Science Basic Features of Pseudo-Scientific Thinking • Relies on Anecdotal evidence – Stories and eyewitness testimony • Little if any hard evidence • Tends toward “Conspiracy theories.” • Ad Hoc reasoning – trying to reason in such a way that you get a desired conclusion. • Thinking that if something seems real, then it must be real. • Believing that just because you cannot think of a natural explanation, a phenomenon must be supernatural/Parnormal

35. Ghosts Theory 1 – There are ghosts, that is, the disembodied spirits of the deceased. Evidence? – • Anecdotal • EVPs • Surges in Electromagnetic activity • Photos & Videos Theory 2 – There are not ghosts. People are mistaken about the evidence Counter Evidence? – ….. In each case the counter evidence is simply an alternative explanation of the supposed evidence in favor of ghosts.