This conclusion would be of little service in supporting Fisher's rigorous contentions! Our constructive theory concerning the relations of reserves and deposits, or reserves and demand liabilities, must wait for later discussion, in the chapter on "Bank Assets and Bank Reserves" in Part III. It will there be maintained that there are no "normal" or "static" laws governing the percentage of reserves to demand liabilities, or to deposits, that the reserve function of money is a _dynamic_ function, and that its whole explanation must be found in dynamic considerations. For the present, I am content to have analyzed two widely divergent views, one the extreme view of Professor Fisher, representing the quantity theory in its utmost rigor, and the other, the view of Professor Taussig, who virtually surrenders the quantity theory in complex modern conditions. In between these two writers, verging more toward Fisher than toward Taussig, will be found, with great individual variation, the rest of the quantity theorists. The quantity theory, as an instrument of prediction, becomes important only to the extent that Fisher's view is maintained. CHAPTER X "NORMAL" VS. "TRANSITIONAL" TENDENCIES The Quantity Theory, as a causal theory, is, then, little altered by the passage from a hypothetical, creditless economy to the actual world, where a vast deal of credit is used,--particularly in Professor Fisher's hands. Of the different kinds of credit, only deposits subject to check are recognized as directly influencing prices, and deposits subject to check are controlled by the volume of money. The causal theory[183] remains, then, as follows: if M be increased, it will increase M' proportionately; it will not change the V's; it cannot increase T; to keep the equation straight, therefore, P must rise in proportion to the rise in M. A decrease of M, reducing M' proportionately, leaving V's and T unchanged, must proportionately reduce P. P is passive. A change in P cannot sustain itself, unless it be due to a prior change in T, the V's, M or M'.