Lecture 5

Question 1

How can we test hypothesis?

Answer 1

• We cannot test hypothesis itself, they are too general or too theoretical
• We can check its observational implications = its predictions

Symbols:

• Hypothesis H entails observational claim O
• We can check whether O is true or false
• We think that this tells us something about the adequacy of H

Question 2

What are two possible outcomes of the test of an observational claim?

Answer 2

• We observe the claim to be true; however, it is still possible that the hypothesis is false. Observing the claim to be true thus does not give us certainty that the hypothesis is true
• We observe the claim to be false; then it must be that the hypothesis is false. Observing that the claim is false, must give us certainty that the hypothesis is false

Question 3

What was Karl Popper’s idea on induction?

Answer 3

Popper focuses mainly on refutation. Thus, he rejected induction because any confirmation is an inductive process.

Question 4

According to Popper, how can scientists attempt to falsify hypothesis?

Answer 4

• If the hypothesis is falsified, scientists must abandon it
• If the hypothesis is not falsified, it survives the next test, but receives no confirmation
• Popper believed that Hume’s problem of induction was unsolvable

–> Method of trial and error

Question 5

What are the lessons drawn by Popper about hypothesis?

Answer 5

• Any attempt to confirm a hypothesis by showing that it entails true observational claims relies on an invalid argument
• Any attempt to refute a hypothesis by showing that it entails false observational claims relies on valid arguments
• We should pursue only refutation, and abandon confirmation of hypotheses

Question 6

Where do hypothesis come from according to Popper?

Answer 6

• Common belief that scientists create hypotheses freely
• Scientists use any form of inspiration; from dreams to observations is legitimate
• But Popper: basing hypothesis on observations does not give us any reason to believe in them = induction

Thus: Context of discovery and context of justification

Question 7

Explain context of discovery and context of justification by Popper

Answer 7

Context of discovery

• Phase in which scientists freely conjecture hypotheses
• There are no rules or standards

Context of justification

• Phase in which scientists test hypotheses
• Phase of logic and rigour
• Assures objectivity of science

Question 8

What did Popper say about falsification as hallmark of science?

Answer 8

If falsification is the scientific method, then it is also the hallmark of science. It can be used to demarcate science from non-science: practitioners of a discipline must be able to say what would falsify their hypotheses or what outcome a hypothesis rules out, otherwise the discipline is a pseudo-science

Question 9

What are four criticisms of falsificationism?

Answer 9

• Refutation is less straightforward than Popper assumed
• Lack of accord with scientific practice
• Popper neglects possible ways of making confirmation more rigorous
• Some valuable scientific hypotheses seem not to be falsifiable