Chapter 1 - What is science?
One of the main tasks of philosophy of science is to understand how techniques such as
experimentation, observation, and theory construction have enabled scientists to unravel so
many of nature’s secrets.
Pseudoscience
- Karl Popper thought that a scientific theory should be falsifiable.
- the theory makes predictions which are capable of being tested (and might be
wrong)
Chapter 2 - Scientific inference
Scientists arrive at their beliefs by a process of reasoning or inference.
Deduction = Inference following the property: if the premises are true, then the conclusion
must be true too.
- All Frenchmen like red wine
Pierre is a Frenchman
-------------------------------------
Therefore, Pierre likes red wine
Induction = Inference where you move from the premises about objects that we have
examined to conclusions about objects of the same sort that we haven’t examined. We move
from limited data to a more general conclusion.
- The first five eggs in the box were good
All eggs have the same best-before date stamped on them
-------------------------------------
Therefore, the sixth egg will be good too
With induction we can find good evidence for scientific theories
With deduction we can find proof for scientific theories.
Hume’s problem of induction
- He argued that induction cannot be rationally justified at all.
- For induction to be rational we need to presuppose ‘uniformity of nature’.
- the assumption that objects we haven’t examined will be similar to those of
the same sort we have examined.
- Hume says we cannot prove uniformity of nature
Inference to best explanation (IBE)
- The cheese in the larder has disappeared, apart from a few crumbs
Scratching noises were heard coming from the larder last night
-------------------------------------
Therefore, the cheese was eaten by a mouse
- How do we decide which hypothesis is the ‘best’?
- Simplicity
Causal inference
- The first step is to see whether two attributes are correlated.
- Correlation does not imply causation
, Controlled experiment = all factors other than the one examined be held constant between
two groups.
Randomized controlled trial (RCT) = The initial division of the patients into two groups must
be random. This helps eliminate the effect of confounding factors on the outcome of interest.
RCT is niet feasible in all areas of science for either practical or ethical reasons.
Probability has both an objective and a subjective guise. In its objective guise, probability
refers to how often things in the world happen, or tend to happen. In its subjective guise,
probability is a measure of rational degree of belief.
Conditionalization = updating your credence in the light of new information, upon learning
evidence e, Pnew(H) should equal P(H/e). Some philosophers wish to use updating by
condalization as a general model of scientific inference. This is called the Bayesian view of
scientific inference.
Chapter 3 - Explanation in science
One important aim of science is to try and explain what happens in the world around us. But
what exactly is a scientific explanation?
Hempel’s covering law model of explanation
- To give a scientific explanation is to provide a satisfactory answer to an
explanation-seeking-why-question.
- Scientific explanations typically have the logical structure of an argument, i.e. a set of
premises followed by a conclusion.
1. The premises should entail the conclusion, the argument should be a deductive one.
2. The premises should all be true.
3. The premises should consist of at least one general law. These are called laws of
nature.
- General Law
Particular fact
→
Phenomenon to be explained
- The phenomenon to be explained is called the explanandum. The general laws and
particular facts that do the explaining are called the explanans.
- Explanations are structurally symmetric.
- There are cases that fit the covering law model but intuitively do not count as genuine
scientific explanations. These cases suggest that Hempel’s model is too liberal - it
allows in things that should be excluded.
Case (i): the problem of symmetry
- Light travels in straight lines
Laws of trigonometry
Angle of elevation of sun is 37 degree
Flagpole is 15 metres high
→
Shadow is 20 metres long
- A problem arises if we swap the explanandum and the particular fact.
One of the main tasks of philosophy of science is to understand how techniques such as
experimentation, observation, and theory construction have enabled scientists to unravel so
many of nature’s secrets.
Pseudoscience
- Karl Popper thought that a scientific theory should be falsifiable.
- the theory makes predictions which are capable of being tested (and might be
wrong)
Chapter 2 - Scientific inference
Scientists arrive at their beliefs by a process of reasoning or inference.
Deduction = Inference following the property: if the premises are true, then the conclusion
must be true too.
- All Frenchmen like red wine
Pierre is a Frenchman
-------------------------------------
Therefore, Pierre likes red wine
Induction = Inference where you move from the premises about objects that we have
examined to conclusions about objects of the same sort that we haven’t examined. We move
from limited data to a more general conclusion.
- The first five eggs in the box were good
All eggs have the same best-before date stamped on them
-------------------------------------
Therefore, the sixth egg will be good too
With induction we can find good evidence for scientific theories
With deduction we can find proof for scientific theories.
Hume’s problem of induction
- He argued that induction cannot be rationally justified at all.
- For induction to be rational we need to presuppose ‘uniformity of nature’.
- the assumption that objects we haven’t examined will be similar to those of
the same sort we have examined.
- Hume says we cannot prove uniformity of nature
Inference to best explanation (IBE)
- The cheese in the larder has disappeared, apart from a few crumbs
Scratching noises were heard coming from the larder last night
-------------------------------------
Therefore, the cheese was eaten by a mouse
- How do we decide which hypothesis is the ‘best’?
- Simplicity
Causal inference
- The first step is to see whether two attributes are correlated.
- Correlation does not imply causation
, Controlled experiment = all factors other than the one examined be held constant between
two groups.
Randomized controlled trial (RCT) = The initial division of the patients into two groups must
be random. This helps eliminate the effect of confounding factors on the outcome of interest.
RCT is niet feasible in all areas of science for either practical or ethical reasons.
Probability has both an objective and a subjective guise. In its objective guise, probability
refers to how often things in the world happen, or tend to happen. In its subjective guise,
probability is a measure of rational degree of belief.
Conditionalization = updating your credence in the light of new information, upon learning
evidence e, Pnew(H) should equal P(H/e). Some philosophers wish to use updating by
condalization as a general model of scientific inference. This is called the Bayesian view of
scientific inference.
Chapter 3 - Explanation in science
One important aim of science is to try and explain what happens in the world around us. But
what exactly is a scientific explanation?
Hempel’s covering law model of explanation
- To give a scientific explanation is to provide a satisfactory answer to an
explanation-seeking-why-question.
- Scientific explanations typically have the logical structure of an argument, i.e. a set of
premises followed by a conclusion.
1. The premises should entail the conclusion, the argument should be a deductive one.
2. The premises should all be true.
3. The premises should consist of at least one general law. These are called laws of
nature.
- General Law
Particular fact
→
Phenomenon to be explained
- The phenomenon to be explained is called the explanandum. The general laws and
particular facts that do the explaining are called the explanans.
- Explanations are structurally symmetric.
- There are cases that fit the covering law model but intuitively do not count as genuine
scientific explanations. These cases suggest that Hempel’s model is too liberal - it
allows in things that should be excluded.
Case (i): the problem of symmetry
- Light travels in straight lines
Laws of trigonometry
Angle of elevation of sun is 37 degree
Flagpole is 15 metres high
→
Shadow is 20 metres long
- A problem arises if we swap the explanandum and the particular fact.
