_X_. Let them have altered; for instance, at the end of the five years, let them have been doubled in value. Now, because your assertion is this--simply by doubling in value, B shall command a double quantity of A--it follows inevitably, Phædrus, that besoms, having doubled their value in five years, will at the end of that time command a double quantity of barouches. The supposition is, that six hundred thousand, at present, command one barouche; in five years, therefore, six hundred thousand will command two barouches? _Phæd_. They will. _X_. Yet, at the very same time, it has already appeared from your argument that twelve hundred thousand will command only one barouche; that is, a barouche will at one and the same time be worth twelve hundred thousand besoms, and worth only one fourth part of that quantity. Is this an absurdity, Phædrus? _Phæd_. It seems such. _X_. And, therefore, the argument from which it flows, I presume, is false? _Phæd_. Scavenger of bad logic! I confess that it looks so. _Phil_. You confess? So do not I. You die "soft," Phædrus; give me the cudgels, and I'll die "game," at least. The flaw in your argument, X., is this: you summoned Phædrus to invert his proposition, and then you extorted an absurdity from this inversion. But that absurdity follows only from the particular form of expression into which you threw the original proposition. I will express the same proposition in other terms, unexceptionable terms, which shall evade the absurdity. Observe. A and B are at this time equal in value; that is, they now exchange quantity for quantity. Or, if you prefer your own case, I say that one barouche exchanges for six hundred thousand besoms. I choose, however, to express this proposition thus: A (one barouche) and B (six hundred thousand besoms) are severally equal in value to C. When, therefore, A doubles its value, I say that it shall command a double quantity of C. Now, mark how I will express the inverted case. When B doubles its value, I say that it shall command a double quantity of C. But these two cases are very reconcilable with each other. A may command a double quantity of C at the same time that B commands a double quantity of C, without involving any absurdity at all. And, if so, the disputed doctrine is established, that a double value implies a double command of quantity; and reciprocally, that from a doubled command of quantity we may infer a doubled value. _X_. A, and B, you say, may simultaneously command a double quantity of C, in consequence of doubling their value; and this they may do without absurdity. But how shall I know _that_, until I know what you cloak under the symbol of C? For if the same thing shall have happened to C which my argument assumes to have happened to B (namely, that its value has altered), then the same demonstration will hold; and the very same absurdity will follow any attempt to infer the quantity from the value, or the value from the quantity.