Some Reflections on Hume on Existence

Some Reflections on Hume on Existence Stanley Tweyman In this paper, I focus on two claims which Hume makes with regard to existence. The first, which appears in a single paragraph inA Treatise ofHumanNature 1.2.6,1 is that existence cannotbe distinguishedfrom what we believe exists by a "distinction ofreason." The second appears in the Dialogues Concerning Natural Religion when Cleanthes criticizes Demea's a priori argument. Much of Cleanthes' criticism of Demea's argument is developed from the Humean claim that, "Whatever we conceive as existent, we can also conceive as non-existent."2 My efforts are directed to showing that, although Hume takes very little space developing each of these points, certain difficulties attend each claim—difficulties which Hume either does not (in the case of the first) or cannot (in the case of the second) address when the claim itself is being made. Distinctions ofReason and the Thought ofExistence Among the distinctions which Hume introduces very early in the Treatise is that between simple and complex perceptions. Simple perceptions are those which admit of no distinction or separation, whereas those which are complex can be distinguished into the simple perceptions of which they are composed through the power that the imagination possesses ofproducing a separation wherever it perceives a difference. A simple perception, therefore, is a perceptual primitive that is not reducible into parts, that is, into the other more basic perceptions. Hume argues that although simple perceptions are not amenable to further distinctions in terms of parts, they are still susceptible to distinctions ofreason. As examples ofthis distinction,he speaks of "figure and the body figur'd; motion and the body movM" (T 24). The actual example employed in his discussion (T 25) is the distinction between the colour and figure in a globe of white marble. Hume points out that when presented with a globe ofwhite marble, the colour is inseparable and indistinguishable from the form or figure. However, ifwe also observe aglobe ofblack marble and a cube ofwhite marble, and compare them with the globe of white marble, we will be able to distinguish the colour and figure of the latter through the resemblances it has with the other two objects. That is, the colour of the globe resembles the colour of the cube, and the figure of the globe Volume XVIII Number 2 137 STANLEY TWEYMAN resembles the figure of the black marble. The awareness of these resemblances Hume refers to as "akind ofreflection" or "comparison," and that to which we are attending—in this case the colour of the figure—he refers to as an "aspect" (T 25). Thus, although simple perceptions lack parts, they do possess aspects—aspects which are discovered through finding resemblances between the perception in question and others: "we consider the figure and colour together, since they are in effect the same and undistinguishable; but still view them in different aspects, according to the resemblances, of which they are susceptible" (T 25). The factthatHume offers a separate name for the operation under discussion makes it appear as though it is a separate operation ofthe mind not yet covered in his discussion. However, this is not the case. Distinctions ofreason are made through comparing an idea with other ideas in order to determine certain resemblances between them. But all comparisons between ideas are regarded by Hume as attempts to establish philosophical relations between them: "The word Relation is ... used ... for that particular circumstance, in which, even upon the arbitrary union of two ideas in the fancy, we may think proper to compare them" (T 13). The text reveals that by the expression "that particularcircumstance"in the precedingquotation Hume isreferring to some resemblance or other which enables the two ideas to be compared: "resemblance: ... is a relation, without which no philosophical relation can exist; since no objects will admit of comparison, but what have some degree ofresemblance" (T 14). What follows from this discussion is that distinctions of reason are nothing but the determination ofphilosophical relationsbetween a certain idea and others. Since philosophical relations exist between complex ideas, and since all distinctions ofreason are nothing but the establishment of philosophical relations, it follows that distinctions of reason can occur...