Scientific Inferences

Question 1

Argument

Answer 1

premise»> inference»> conclusion

Includes an initial statement, the premise, intended to determine the degree of truth of another statement, the conclusion

Question 2

Premise

Answer 2

What we base a conclusion off of

Ex. we have observed 9 red things… conclusion: the next one will be red

Question 3

Inference

Answer 3

the act or process of reaching a conclusion about something from known facts or evidence

Question 4

Types of inferences (5)

Answer 4

1. DIRECT INFERENCE: “We observe 33% of individuals to be red, therefore, in the population, 33 % of individuals are red.” When you assume that the reality will look the same as the sample group. (inductive)
2. PROJECTION: “We observed 9 red individuals, therefore, the next individual we observe will be red.” When you observe a sample group to guess what will happen next. (inductive)
3. GENERALIZATION: “We have observed nine individuals of type X. Each of them was red, therefore, we accept the claim that all X are red.” When you generalize something by a hypothesis that everything will be like that. (inductive)
4. MODUS PONENS: “Premise 1: if P then Q. Premise 2: P. Conclusion: Q.” We accept a number of assumptions as true, therefore, we accept the implications of these assumptions. (deductive)
5. MODUS TOLLENS: “Premise 1: if P then Q. Premise 2: not Q. Conclusion: not P.” We accept a conditional as true, and observe that its consequent is false, therefore, we conclude that H is false.
   (deductive)

Question 5

Deductive Inference

Answer 5

Deductive inferences rearrange current knowledge in such a way that they merely explicate what we already know.

Conclusions from good (“valid”) deductive
inferences and true premises are NECESSARILY true

Question 6

Inductive Inference

Answer 6

They go beyond information we already have, thus they amplify our knowledge when they are used.

Conclusions from good inductive inferences and
true premises are fallible – THEY MIGHT BE FALSE

Question 7

! Problems with Inductive inferences

Answer 7

That they might be false, don’t have enough information to be conclusive

Question 8

Hume’s problem of induction

Answer 8

(An argument against the justifiability of induction. Its premises are:)

• That a given inductive inference rule cannot be justified deductively.
• That the justification of a given inference rule itself consists of an inference from true premises.
• That every inference is either inductive or deductive.

(When inferring I inductively, we must appeal to another (inductive) inference rule
J to justify this induction. But that raises the issue of how to justify J, which would
require appealing to another inference rule K, ….. [infinite regress]&raquo_space;» Consequently, no inductive inference rule can be justified)

Question 9

! Foundationalism vs Coherentism

Answer 9

F: Identifying the basic claims from which the claims to be justified can be inferred.

C: The claims to be justified from a coherent system with the set of other claims already accepted.

(Both offered by justification)

Question 10

Hypothesis criteria

Answer 10

• A statement that can be either true or false
• A statement that is not necessarily true or false
• A statement that either has some generality (e.g. “all X in domain D…”), or that is about some unobservable (exclude statements like “this table is red”)

Question 11

! How to test a hypothesis

Answer 11

1. Formulate a hypothesis H
2. Deduce observable consequences {Ci} from H.
3. Test whether {Ci} is true or not.
4. If {Ci} is false, infer that H & {AHj} is false.
5. If {Ci} is true, increase confidence in H

Question 12

Falsification

Answer 12

An event – The observation that an implication of a hypothesis is not true, which by modus tollens then implies the falsity of the hypothesis.

Question 13

Hypothetico-Deductive (HD) method:

aka, how do you falsify a hypothesis?

Answer 13

• Begin by proposing (unproven) hypothesis.
• They derive observable implications from these hypotheses.
• They test these implications and consequently revise their confidence in these hypotheses.
• If the deduced observable consequences are false, infer that the hypothesis is false.

(uses both induction and deduction)

Question 14

Karl Poppers falsification

Answer 14

• Conjecture falsifiable hypotheses.
• Seek to falsify these hypotheses with observable evidence.
• Reject any falsified hypothesis as false.
• Never accept any hypothesis as true – only maintain non-falsified hypotheses as so far not rejected.

Question 15

Falsifiability

Answer 15

Quality of a hypothesis – A good hypothesis has more observable consequences that sets it apart from rival hypothesis.

Question 16

Auxiliary hypothesis

Answer 16

Typically well confirmed Hypothesis
…all the Hypothesis that are assumed to be accurate in order for a test to work as planned

(an assumption needed to draw observable consequences from the main hypothesis.)

Question 17

Ad hoc hypothesis

Answer 17

A hypothesis added to a theory in order to save it from being falsified.

(A modification is ad hoc if it reduces the falsifiability of the hypotheses in question.)

Question 18

Quine-Duhem thesis

Answer 18

We never test a single hypothesis alone, but only in conjunction with various auxiliary hypotheses. A hypothesis can never be tested in isolation.

Question 19

Why does the Quine-Duhem thesis present a problem for Popper’s falsification?

Answer 19

For falsifying the hypothesis: be confident that it’s not the auxiliary hypotheses responsible for falsity of the consequence
»>No asymmetry between falsification and confirmation!