A Third Type of Distinction in the Treatise

In this paper, I resolve a potential contradiction between two of Hume's central tenets: that complex perceptions consist of simple perceptions and that distinct things are separable. The former implies that a complex perception is not separable from its constituent simple perceptions, as a change in its constituents destroys its identity. The latter entails that the complex perception is separable from these simple perceptions, since it is distinct from them. This is a contradiction. I resolve it by appealing to a third kind of distinction in addition to the two kinds Hume mentions: real distinctions and distinctions of reason. This third distinction is a partial distinction. I argue that just as the separability principle does not apply to distinctions of reason, neither does it apply to perceptions that are only partially distinct from other perceptions. Hence, the apparent contradiction is resolved.