Alan Greenspan is dead at one hundred, and the BBC reports that he became, as Federal Reserve chairman, 'the world's most high-profile banker.' That is a remarkable thing to be said of any single man in a republic built on the distributed judgments of millions of buyers and sellers. I say that not to diminish him, but to begin with the right question: what is a central banker for, and what are the limits of any one mind — however formidable — set over the price of money?

I could not have known, in my own century, the precise machinery of a modern central bank. I speak with appropriate humility on the engineering of monetary policy. But the institutional question is perfectly within my remit. Every market, to function honestly, requires a framework: contract law to enforce promises, a judiciary to adjudicate disputes, and — where the scale of exchange produces systemic risk — some public authority to prevent the failures of particular merchants from cascading into the ruin of the whole. The sovereign's duty to maintain justice does not stop at the counting-house door.

Greenspan's long tenure — spanning, as The Hill notes, five presidential terms and the administrations of Reagan, both Bushes, and Clinton — coincided with what many called the 'Great Moderation,' a period of unusual economic stability. Yet it ended, by most informed accounts (inference, not recollection on my part), in the financial crisis of 2008, in which the very instruments of credit that had proliferated under light regulatory oversight proved to carry systemic dangers invisible to any individual trader. This is precisely the failure I warned against when I observed that merchants, following their private interest, cannot be expected to act as guardians of the public interest — and that no invisible hand reaches into a market where information is hidden and consequences are diffuse.

I am told that Greenspan, in his later years, publicly acknowledged that he had placed too much faith in the self-correcting capacity of financial markets — that he had believed the enlightened self-interest of lending institutions would protect their shareholders and, by extension, the public. I find this admission admirable in its honesty and sobering in its implication. The disposition to trust the market's judgment is, in general, sound; I argued it at length. But trust is not the same as abdication. The pin factory produces more pins when labor is divided, but it still requires a factory — a structure, a discipline, a set of rules that the individual worker did not invent and cannot maintain alone.

The moral of Greenspan's career, as I read it from this distance, is not that markets fail and must be supplanted by authority. It is the older and more careful lesson: that the invisible hand works only within a framework of law, transparency, and institutional accountability. Where that framework is weakened — whether by a chartered monopoly, a captured regulator, or a financial instrument too complex to be understood by those who must bear its consequences — the public pays the price, and the consumer, as always, pays it last and longest. The question his career poses to our present moment is the same question I posed to the East India Company: who is watching the watchers, and by what law do they answer?