And as Brad DeLong often points out, any insightful points you make about economics have more often than not already been made (and made more eloquently) by John Maynard Keynes. This is from the beginning of The Consequences to the Banks of a Collapse in Money Values (1931), a piece that I've actually been wanting to have a reason to share on here (he talks about 1921 in here, which is another reason why I like it). I think it speaks to the points about the incentives of banks under free banking that I made in the prior post.
"A year ago it was the failure of agriculture, mining, manufactures, and transport to make normal profits, and the unemployment and waste of productive resources ensuing on this, which was the leading feature of the economic situation. To-day, in many parts of the world, it is the serious embarrassment of the banks which is the cause of our gravest concern. The shattering German crisis of July 1931, which took the world more by surprise than it should, was in its essence a banking crisis, though precipitated, no doubt, by political events and political fears. That the top-heavy position, which ultimately crumbled to the ground, should have been built up at all, was, in my judgement, a sin against the principles of sound banking. One watched its erection with amazement and terror. But the fact which was primarily responsible for bringing it down was a factor for which the individual bankers were not responsible and which very few people foresaw—namely, the enormous change in the value of gold money and consequently in the burden of indebtedness which debtors, in all countries adhering to the gold standard, had contracted to pay in terms of gold.
Let us begin at the beginning of the argument. There is a multitude of real assets in the world which constitute our capital wealth—buildings, stocks of commodities, goods in course of manufacture and of transport, and so forth. The nominal owners of these assets, however, have not infrequently borrowed money in order to become possessed of them. To a corresponding extent the actual owners of wealth have claims, not on real assets, but on money. A considerable part of this "financing" takes place through the banking system, which interposes its guarantee between its depositors who lend it money, and its borrowing customers to whom it loans money wherewith to finance the purchase of real assets. The interposition of this veil of money between the real asset and the wealth owner is a specially marked characteristic of the modern world. Partly as a result of the increasing confidence felt in recent years in the leading banking systems, the practice has grown to formidable dimensions. The bank-deposits of all kinds in the United States, for example, stand in round figures at $50,000,000,000; those of Great Britain at £2,000,000,000. In addition to this there is the great mass of bonded and mortgage indebtedness held by individuals.
All this is familiar enough in general terms. We are also familiar with the idea that a change in the value of money can gravely upset the relative positions of those who possess claims to money and those who owe money. For, of course, a fall in prices, which is the same thing as a rise in the value of claims on money, means that real wealth is transferred from the debtor in favour of the creditor, so that a larger proportion of the real asset is represented by the claims of the depositor, and a smaller proportion belongs to the nominal owner of the asset who has borrowed in order to buy it. This, we all know, is one of the reasons why changes in prices are upsetting.
But it is not to this familiar feature of falling prices that I wish to invite attention. It is to a further development which we can ordinarily afford to neglect but which leaps to importance when the change in the value of money is very large—when it exceeds a more or less determinate amount.
Modest fluctuations in the value of money, such as those which we have frequently experienced in the past, do not vitally concern the banks which have interposed their guarantee between the depositor and the debtor. For the banks allow beforehand for some measure of fluctuation in the value both of particular assets and of real assets in general, by requiring from the borrower what is conveniently called a "margin." That is to say, they will only lend him money up to a certain proportion of the value of the asset which is the "security" offered by the borrower to the lender. Experience has led to the fixing of conventional percentages for the "margin" as being reasonably safe in all ordinary circumstances. The amount will, of course, vary in different cases within wide limits. But for marketable assets a "margin" of 20 per cent to 30 per cent is conventionally considered as adequate, and a "margin" of as much as 50 per cent as highly conservative. Thus provided the amount of the downward change in the money value of assets is well within these conventional figures, the direct interest of the banks is not excessive;—they owe money to their depositors on one side of their balance-sheet and are owed it on the other, and it is no vital concern of theirs just what the money is worth. But consider what happens when the downward change in the money value of assets within a brief period of time exceeds the amount of the conventional "margin" over a large part of the assets against which money has been borrowed. The horrible possibilities to the banks are immediately obvious. Fortunately, this is a very rare, indeed a unique event. For it had never occurred in the modern history of the world prior to the year 1931. There have been large upward movements in the money value of assets in those countries where inflation has proceeded to great lengths. But this, however disastrous in other ways, did nothing to jeopardise the position of the banks; for it increased the amount of their "margins." There was a large downward movement in the slump of 1921, but that was from an exceptionally high level of values which had ruled for only a few months or weeks, so that only a small proportion of the banks' loans had been based on such values and these values had not lasted long enough to be trusted. Never before has there been such a world-wide collapse over almost the whole field of the money values of real assets as we have experienced in the last two years. And, finally, during the last few months—so recently that the bankers themselves have, as yet, scarcely appreciated it—it has come to exceed in very many cases the amount of the conventional "margins." In the language of the market the "margins" have run off. The exact details of this are not likely to come to the notice of the outsider until some special event—perhaps some almost accidental event—occurs which brings the situation to a dangerous head. For, so long as a bank is in a position to wait quietly for better times and to ignore meanwhile the fact that the security against many of its loans is no longer as good as it was when the loans were first made, nothing appears on the surface and there is no cause for panic. Nevertheless, even at this stage the underlying position is likely to have a very adverse effect on new business. For the banks, being aware that many of their advances are in fact "frozen" and involve a larger latent risk than they would voluntarily carry, become particularly anxious that the remainder of their assets should be as liquid and as free from risk as it is possible to make them. This reacts in all sorts of silent and unobserved ways on new enterprise. For it means that the banks are less willing than they would normally be to finance any project which may involve a lock-up of their resources."
To say that banks are less willing to lock up their resources is equivalent to saying that banks have liquidity preference too.
An advantage of central bankers - maybe even their one saving grace - is that central bankers do not have any liquidity preference to speak of.