Warmup questions:

Do you have any ideas that aren’t traceable to sensory impressions?

What is the difference between something believed and something imagined?

Do you have any beliefs about the physical world that are not rooted in beliefs about causes?

If one says ‘A causes B’ do they mean more than ‘A is always followed by B’?

If we think there is more to believing that A causes B than believing that A is always followed by B then is the “something extra” based on a sensory impression?

 Section II Ideas and Impressions

-mind experiences only ideas and impressions.
- force and  vivacity

(end of Par.5) “...all our ideas or more feeble pereceptions are copies of our impressions or more lively ones.”  (empiricism in a nutshell)
Proofs: (par. 6)
argument 1- If you don’t believe it find me a counterexample.
argument 2- people missing certain sensory capacities are unable to have certain ideas (par. 7)

contradictory phenomena-the paint chip problem

Section III-Of the Association of Ideas

-mind has little control over impressions or memories
-But what of imagination?   Our thoughts seem to go together as if compelled by “gentle forces”:
 i) resemblance
 ii) cause and effect
 iii) contiguity.

Part IV _Sceptical Doubts Concerning the

objects of human reason can be divided into one of two kinds:
 i) relations between ideas
 ii) matters of fact

Mathematical truths are of the first kind.

How do we go from brute sensory impressions to knowledge of the physical world?

Hume’s answer: causal reasoning

How do we gain knowledge of cause and effect?
Solely from experience.  We “know” that x causes y because we’ve always observed x precede y.  However, there is no a priori reason to think that just the opposite might have happened.

Hume makes the following observation: (par. 3)
We go from:
i) Object (or event) A always results in effect B. to
ii) objects (or events) similar to A will be followed by an effect similar to B.
But what allows an inference from (i) to (ii)?

Section V

Why do we think we have the right to infer from a new instance of A the forthcoming existence of a new instance of B?  Hume gives a psychological explanation.

Par. 6: it is only custom “which renders our experience useful to us and makes us expect for the future a similar train of events with those which have appeared in the past.”

Part II-Section V
The difference between ideas and impressions can be made in terms of force and vivacity but the same kind of distinction holds between beliefs and imaginings.

This helps to further explain the process of causal reasoning, why we end up believing something even if it is not immediately present to our senses.

How the process of causal reasoning works:

1. We discover an association between events of two different types (e.g. flames and heat)
2. We discover, through experience, constant or regular conjunction.
3. The mind develops a habit of associating the two.
4. Later, when the first occurs the mind automatically forms the idea of the other.
5. If when the one event (cause) occurs it occurs as a sensation or as an idea of memory ( having great F and V), the mind is led to form the idea of the other event (effect) and transfer some of the F and V to the newly formed idea.
6. The idea of the effect that gets formed is boosted from being a mere imagining to being a belief.
 
 
 
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