V is defined,[206] not as the number of times a given dollar is exchanged in a given year (the "coin-transfer" notion), but as a social average based on the average number of coins which pass through _each man's_ hands, divided by the average amount held by him (the "person-turnover" concept of velocity.) V' is similarly defined. Fisher asserts that both concepts, if correctly employed, lead to the same result. I would point out one important difference between them here: if money is _short-circuited_, if, _i. e._, a part of the economic community loses its incomes, or finds its incomes reduced, then the "velocity of money," on the "coin-transfer" basis is reduced, provided the "person-turnover" average remains the same, while on the "person-turnover" basis the velocity will remain unchanged. It is clearly the "coin-transfer" concept which is fundamental, from the standpoint of the equation of exchange, and Fisher feels justified in using the other method only because he considers it an equivalent of the "coin-transfer" concept. I shall later show cases where the distinction between the two concepts is all-important, particularly in the case where T is reduced by the elimination of _middlemen_.[207] The conception of velocity of circulation as a real, unitary entity, a _cause_, in the process of price-determination, is, I suppose, almost as old as the quantity theory itself. It is an essential part of the quantity theory. To me "velocity of circulation" seems to be a mere name, denoting, not any simple cause or small set of causes, which can exert a specific influence, but rather a meaningless abstract number, which is the non-essential by-product of a highly heterogeneous lot of _activities of men_, some of which work one way, and others of which work in another way, in affecting prices. It is at best a passive _resultant_ of conflicting and divergent tendencies, and has, to my mind, no more _causal_ significance than the average of the abstract numbers of yards gained by both sides, heights and weights of players, kick-offs, and minutes taken out for injuries, would have on the result of the Yale-Harvard game. The real causes of changes in prices lie deeper! I should expect V and V' to be the most highly flexible factors in the equation of exchange, and should expect to be able to keep the equation straight, in a great variety of situations, by allowing the V's to vary.