A name for the contested view that it is impossible to derive an ‘ought’ from an ‘is’ by logic alone or in other words, that there is no logical bridge over the gap between fact and value. Hume’s own statement is in the Treatise of Human Nature, iii. 1. 1, where he wrote that it seems ‘altogether inconceivable that this new relation [ought] can be derived from others, which are entirely different from it’. The ‘law’ in fact appears as something of an afterthought to other discussion.