The author of Unlearning Economics has written two good posts on the endogenous nature of money (i.e., the notion that the money supply adjusts to the demand for money). I agree with the author's assertion that recognizing the endogenous nature of money is important in order for policymakers to properly address issues relating to financial instability.
Just to add to this discussion, the key aspect about the endogenous nature of money is its ambivalent effects on the working of the economic system. On the one hand, as stressed by many post-Keynesian monetary economists (especially circuitistes and modern monetary theorists), the endogeneity of money enables both the level of investment and growth to surpass what it would otherwise be in a context of self-financing....
On the other hand, as recently emphasized by the staff economist of the Bank for International Settlements (BIS), the endogenous nature of money, by allowing investment to surpass the capacity of self-financing, also acts to intensify the inherent risks and instability of the modern economy (in which finance plays a critical role) by creating the conditions that lead to unsustainable booms in credit and asset prices that "can eventually lead to serious financial strains and derail the world economy" (Borio, 2011:27).Fictional Reserve Banking
Thoughts on endogenous money