13. The Problem of Induction
0. Hume: some biography
• Revolutionary thinker
1. Hume's "Fork"
Relations of Ideas
Relations of Ideas:
“Propositions of this kind are discoverable by the mere operation of thought, without
dependence on what is anywhere existent in the universe. Though there never were a
circle or triangle in nature, the truths demonstrated by Euclid would for ever retain their
certainty and evidence.”
Don’t need to go out and see if these answers are true, just think.
Without consultation and checking, you are able to see the truth
• Three times five is equal to half of thirty
• The square of the hypotenuse is equal to the sum of the square of
the two sides
• Bachelors are unmarried males
• Pythagoras’ Theorem
Matters of Fact:
Not ascertained in the same manner as relations of ideas.
Our evidence of their truth is not of the same nature as that of relations of ideas.
The contrary of any matter of fact is possible:
–It never implies a contradiction
–The contrary is entirely conceivable (imaginable)
These need to be checked and confirmed
• The monkey is on the carpet
• Brad is nourishing to human beings
• My friend Peter is in France
Present testimony of our senses
Records of our memory
2. Relations of Cause and Effect
“All reasoning concerning matters of fact seems to be founded on the relation of cause
Your friend is in France.
–Inferred from a letter received from him
There once were human beings on the island.
–Inferred from the discovery of a watch
A person is present. –Inferred from hearing articulate voice and rational discourse in the dark
The relations of cause and effect are not themselves relations of ideas; they are matters
“The mind can never possibly find the effect in the supposed cause, by the most accurate
scrutiny and examination.”
Not relations of ideas
o Explosion of gunpowder
o Attraction of magnets
o Conservation of momentum
Hume’s basic message is that, if we think carefully about cases of causeeffect
relationships, we discover that in fact we have no impression of causal power, no
impression of necessary connection…
We have no impression of any link between the events.
…All we have is an impression of one event followed by an impression of another event.
o Billiard balls
Yellow ball hits the red ball
The red ball moves off
• May hypothesize link
• No detectable link
o Voluntary motions (Acts of will or volitions)
You will to raise your arm and your arm goes up
o How can the mind act on the body