Page:An Enquiry Concerning Human Understanding - Hume (1748).djvu/265

 obvious Reflection, pronounce one Thing not to be another. Or if there be any Difficulty in these Decisions, it proceeds entirely from the undetermin'd Meaning of Words, which is corrected by juster Definitions. That the Square of the Hypotenuse is equal to the Squares of the other two Sides, cannot be known, let the Terms be ever so exactly defin'd, without a Train of Reasoning and Enquiry. But to convince us of the Truth of this Proposition, that where there is no Property, there can be no Injustice, 'tis only necessary to define the Terms, and explain Injustice to be a Violation of Property. This Proposition is, indeed, nothing but a more imperfect Definition. 'Tis the same Case with all those pretended syllogistical Reasonings, which may be found in every other Branch of Learning, except the Sciences of Quantity and Number; and these may safely, I think, be pronounc'd the only proper Objects of Knowledge and Demonstration.

other Enquiries of Men regard only Matter of Fact and Existence; and these are evidently incapable of Demonstration. Whatever is may not be. No Negation of a Fact can involve a Contradiction. The Non-existence of any Being, without Exception, is as clear and distinct an Idea as its Existence. The Proposition, which affirms it not to be, is no less con-