Lecture 2 Flashcards
What is interference?
The act or process of reaching a conclusion about something from known facts or evidence. We use observations, information or known facts to reach a logical conclusion.
Describe inductive and deductive inference
Inductive inference - Creates probable guesses based on patterns. Inductive inference moves from specific observations to a broader conclusion beyond this knowledge (e.g. “all dogs are friendly”). Inductive inference may be false, even if the premises support the conclusion this does not guarantee its truth.
Deductive inference - They are explicated knowledge, to draw conclusions from known facts. Deductive inference goes from a general rule to a specific conclusion (e.g. “a dog is a mammal, so it has a backbone”). Conclusions from good (“valid”) deductive inferences and true premises are necessarily true. So a valid deductive inferences ensure that the conclusion is always true if the premises are true.
Which are the 5 types of scientific interference rules? And tell if they are inductive/deductive
Direct interference (inductive), projective interference (inductive), generalization (inductive), modus ponens (deductive) and modus tollens (deductive).
Describe direct interference
Direct interference draws a conclusion about part of the population based on a sample, without making broad assumptions about individual future observations. E.g. In a sample, we observe 33% of individuals to be red therefore we conclude that in the population 33% of the individuals are red.
Describe projective interference
Projective interference makes a prediction about future observations based on a short series of past observations, what will the next sample be based on past observations? E.g. We have observed 9 individuals as red → conclusion the next individual will be red.
Describe generalization
Generalization makes a universal inference about all individuals in a population based on a number of observations, making a broader assumption than the others. E.g. We have observed 9 individuals of type X as red → hypothesis H “all are red”… we accept the claim that all X are red.
Describe modus ponens
If we have assumed that the hypothesis is true, modus ponens states that if we find the assumption are true, then one can infer the conclusion is true. We have the form: (i) If A then B, (ii) A, therefore (iii) B (if A is true, then we can draw the conclusion that B is also true).
Describe modus tollens
If we have assumed that the hypothesis is true (leading to a certain consequence true), modus tollens states that if we observe the consequence is false, then the hypothesis must be false. We have the form: (i) If A then B, (ii) not B, therefore (iii) not A.
Which are the 5 steps in Hume’s problem of induction
- Hume starts by assuming that there are only to kinds of inferences (inductive and deductive)
- And second, assume that to justify an inductive inference rule I, this rule itself has to be inferred from some premises.
- I cannot be inferred deductively, because there is no necessary connection between past and future inferences.
- Thus, I must be inferred inductively.
- 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.
Describe three ways to dispute Hume
- One way is to deny that scientists need to employ inductive inferences rules to justify their conclusions.
- Another way is to deny the impact of Hume’s argument. These inductive inference rules themselves are not justified, because any search for a foundation leads to an infinite regress.
→ Scientists employ unjustified methods & science is irrational. - Coherentism. The claims to be justified from a coherent system with the set of other claims already accepted. Cojerentis’ answer to Hume’s arguments are less severe, inductive inference rules by not being the foundation of inductive practices rather they may serve as abstract description of such practices and serve as tools to connect them together. Then both the practices and rules are justified if they work well together.
Which are the steps in Hypothetico-Deductive (HD) method?
Step 1: Formulate a hypothesis H.
Step 2: Dedicate observable consequences [C_i] from H.
Step 3: Test: Determine whether [C_i] is true or not.
Step 4 & 5: Confirmation & Falsification
If [C_i] is false, infer that H is false.
If [C_i] is true, increase confidence in H.
Requirements for formulating a good hypothesis H
A statement that can be either true or false, particularly it excludes research questions.
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”)
Requirements for the consequences in HD method
[C_i] must be observable directly or with the help of accurate measurements (e.g. microscope, X-ray, etc.)
Deduction must be valid
[C_i] must be relevant for H
What is falsifiability and falsification?
Falsifiability: This is a measure of the quality of the hypothesis and refers to whether it is at all possible to test the hypothesis in a way that can show it to be false.
Falsification: This is the act of showing that a hypothesis is false by empirical evidence or observations that contradict the hypothesis. If a hypothesis is falsified, it has failed to stand up to empirical testing and should therefore be considered false and rejected.
Describe Popper’s Falsificationism and the problems with falsificationism
Karl Popper means that a hypothesis must be falsifiable to be considered scientific, meaning that there should be potential observations that could show it to be wrong.
Problem 1: Hypotheses without confidence? It is problematic to treat all hypotheses as equally uncertain when some seem to have more support than others.
Problem 2: Modus Tollens for rejecting hypothesis? Falsification is complicated because we often cannot isolate which part of the hypotheses (the main or auxiliary hypotheses) is causing incorrect results.
Problem 3: Ad hoc Modification. Adding ad hoc hypotheses to save a theory from falsification makes the theory less falsifiable and undermines its scientific credibility.
