  Thomas Reid also takes issue with some of Locke’s claims in his Essays on the Intellectual Powers of Man (1785). For Locke succession is a more basic concept than duration – since we arrive at the concept of duration by reflecting on the distances between parts of successions – but Reid argues the reverse is the case. For a succession to exist at all, its parts – either particular impressions or the intervals between them – must themselves already have duration: for if these parts were all entirely lacking in duration, we would be dealing with a purely momentary phenomenon, and hence something which could not contain any kind of succession. Hence succession presupposes duration, and not vice-versa.