From Treatise of Human Nature:
Experiment is experience and observation. Current philosophy was in trouble.
Going from Thales to Socrates, science moved from natural science to moral science.
From Bacon to Hume, a new natural philosophy to a philosophy of human nature.
Like John Locke, the founder of empiricism, Hume wrote on an epistemology that is based on how we interact with the world and information. This new epistemology distinguished between impressions and ideas, their difference being in vividness. Ideas originate in impressions:
1. Complex ideas should be reducible to (basic) impressions. How can you relate colors? Comparisons that help the blind reduce ideas to simple impressions.
2. Principles of association – different kinds of association.
Hume’s Fork (Philosophic Relations)
1. Scientific relations are necessary and invariable. Certitude in simple math versus impressions/facts, which are variable and contingent.
2. Customary relations are matter of fact.
Priority -> Contingency -> Constant conjunction -> Future will be like the past (customary and probable).
The Self is a series of impressions, in flux and moving. But reason can never be the source of a moral action rooted in passion. Not all morals originate in selfishness and passions are just sentiments. There is pleasure in seeing certain kinds of disinterested moral sentiments.