Definitions of Important Terms

any content of the mind of which we are conscious.

Hume speaks of "perceptions of the mind" several times in paragraphs 1 through 3. [text] While he does not offer a definition of "perception of the mind" he gives several examples in those paragraphs and the examples include pains, pleasures, anticipations of the imagination, [text] feeling anger, and thinking of anger [text]. The phrase "of which we are conscious" appears in paragraph 3. [text]

a perception which involves actual hearing, seeing, feeling, etc., rather than just thinking about these things.

[text] Notice Hume draws the distinction between impressions and ideas in terms of their differing degrees of "liveliness."

a perception of the mind which involves thinking of something instead of actually (first hand) experiencing it. [text]

complex idea:
an idea which is built up from other ideas. [text]

simple idea:
an idea which is not complex.

Hume first uses this term (in the Enquiry) in paragraph 6. [text]

outward sentiment:
an impression of something from the external world, obtained through one of the five senses.

Hume distinguishes outward and inward sentiment in paragraph 5. His claim, there that "all the materials of thinking are derived either from our outward or inward sentiment . . . Or, to express myself in philosophical language, all our ideas . . . are copies of our impressions . . .," [text] shows that he is using "sentiment" as a synonym for "impression."

inward sentiment:
an impression which is of something not from the external world; for example nervousness or anger.

That Hume considers anger to be an impression (or sentiment) is clear from the point (and context) of his example in the second sentence of paragraph 2: "A man in a fit of anger . . ." [text]

innate idea:
an idea which is not derived from impressions.

[text] But Hume admits (indeed, insists) that the term "innate idea"is not clear.

the view that all our knowledge about matters of fact (things which are not required by logical necessity) is derived from experience.