The basic idea of the neutrality of money (though not in those words) surely stems from Hume. (Aristotle is much more abstract.) Hume wrote: 'Money is not, properly speaking, one of the subjects of commerce; but only the instrument which men have agreed upon to facilitate the exchange of one commodity for another. . . If we consider any one kingdom by itself, it is evident, that the greater or less plenty of money is of no consequence; since the prices of commodities are always proportioned to the plenty of money, and a crown in HARRY VII's time served the same purpose as a pound does at present.' (Of Money, 1752) The price level is proportionate to the money stock, with no real effects (long-run neutrality). But Hume knew that (a) this only applies to a closed economy and (b) changes in the money stock have temporary real effects (short-run non-neutrality). Tony Brewer