David Hume

Treatise of human nature

Book I: The understanding

Section 1: The origin of our ideas All the perceptions of the human mind fall into two distinct kinds, which I shall call ‘impressions’ and ‘ideas’. These differ in the degrees of force and liveliness with which they strike upon the mind and make their way into our thought or consciousness. The perceptions that enter with most force and violence we may name ‘impressions’; and under this name I bring all our sensations, passions, and emotions, as they make their first appearance in the soul [= ‘mind’; no religious implications]. By ‘ideas’ I mean the faint images of the others in thinking and reasoning: for example, all the perceptions aroused by your reading this book – apart from perceptions arising from sight and touch, and apart from the immediate pleasure or uneasiness your reading may cause in you. I don’t think I need to say much to explain this distinction: everyone will readily perceive for himself the difference between feeling (·impressions·) and thinking (·ideas·).

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