Full Idea
The greatest weakness in Hume's philosophy is his use of the term 'impression' to refer to both sensations and perceptions.
Clarification
Some impressions involve knowledge, others not
Gist of Idea
Hume mistakenly lumps sensations and perceptions together as 'impressions'
Source
comment on David Hume (Enquiry Conc Human Understanding [1748]) by Roger Scruton - Modern Philosophy:introduction and survey 24
Book Reference
Scruton,Roger: 'Modern Philosophy: introduction and survey' [Sinclair-Stevenson 1994], p.342