Loans are based on the lender's estimation of the borrower's ability to service his debt. The valuation of the collateral is supposed to be independent of the act of lending; but in actual fact the act of lending can affect the value of the collateral. This is true of the individual case and of the economy as a whole. Credit expansion stimulates the economy and enhances collateral values; the repayment or contraction of credit has a depressing influence both on the economy and on the valuation of the collateral. The connection between credit and economic activity is anything but constant—for instance, credit for building a new factory has quite a different effect from credit for a leveraged buyout. This makes it difficult to quantify the connection between credit and economic activity. Yet it is a mistake to ignore it. The monetarist school has done so, with disastrous consequences.
贷款的依据是贷款人对借款人偿债能力的估计。抵押品的估价本应与贷款行为无关，但实际上贷款行为会影响抵押品的价值。个案如此，整体经济也是如此。信贷扩张会刺激经济，提高抵押品的价值；而信贷的偿还或收缩则会对经济和抵押品的价值产生抑制作用。信贷与经济活动之间的联系并不是一成不变的--例如，用于建造新工厂的信贷与用于杠杆收购的信贷所产生的影响就大不相同。因此，很难量化信贷与经济活动之间的联系。然而，忽视这一点是错误的。货币主义学派就是这样做的，并带来了灾难性的后果。
金融炼金术 索罗斯