THE LIMITS OF HUMAN KNOWLEDGE: That the sum of human knowledge has grown since the days of Charlemagne is, I hope, an uncontroversial proposition. Less so is the question of how it has grown. We no longer take the inevitability of progress for granted. Mighty Rome, we know, declined in knowledge as well as power, and much classical learning disappeared after its downfall.
To complicate the question, Nassim Nicholas Taleb has put forward two persuasive, if unnerving, claims about human knowledge. First, social life is ruled by probability rather than mechanical causation. Second, the human mind did not evolve to understand probabilistic outcomes and is constantly inventing fallacious causes and effects. In Taleb's view, we lack the information to decipher the present, much less the future, and so, as individuals and communities, we are always colliding into unpleasant surprises.
It's hard to see how knowledge can accumulate under such conditions.
An answer may be found in Thomas Sowell's brilliant analysis of ideological visions. Sowell examined the positions people took on unconnected issues -- say, government finance of health care and war in Iraq -- and was struck by the fact that the same groups aligned across such issues: if one is pro-government health care one is almost certain to be anti-war, and viceversa. Each of these two opposed visions, he concluded, shared elementary assumptions about human nature and human knowledge.
Both visions agree that people are ignorant and selfish, and prone to faulty decisions in the private and public spheres. But they draw radically different conclusions from this circumstance.
According to the constrained vision, human nature is what it is, making a Talebian existence inescapable. Experts and philosophers, no less than illiterates, will regularly make moral and political decisions based on bad information. Social life should therefore abide by those time-tested rules, processes, and institutions which make the best of our bad characters. Morality should appeal to pride in personal honor and reputation, for example. Economics should promote transactions which increase the general prosperity as a byproduct of personal enrichment.
These are trade-offs for an imperfect world. Adherents of the unconstrained vision dismiss such formalisms with contempt. The flawed human condition, they believe, isn't really the product of our nature but of superstition and malice. The world of Talebian uncertainty can be transcended -- in fact, it has been transcended by the most advanced minds of the age. This brilliant elite commands the knowledge to perfect the human condition, and deals in "solutions" to social and political problems. All it takes is the intellect to articulate a rational plan, and the virtue to implement it.
Once the desirable outcome has been articulated, the only remaining obstacles are, again, superstition and malice. "Running through the tradition of the unconstrained vision," Sowell writes, "is the conviction that foolish or immoral choices explain the evils of the world -- and that wiser or more moral and humane social policies are the solution."
The two visions differ not only on how much knowledge we possess, but on what knowledge is. In the constrained vision, knowledge is primarily inarticulate experience, which resides in processes and institutions like language and the price system. The complex, uncertain Talebian world is held together by tradition: that is, by the evolved wisdom of the many, alive and dead.
In the unconstrained vision, knowledge is identified with rationality, particularly when wielded by a member of the class of advanced minds. The task of this group is to raise the rest of humanity to the moral and intellectual plane it has already attained. Of course, rational solutions will be attacked by predatory interests. Experience is little more than a cloak for these human wolves -- it's something to overcome rather than heed. The Augean stables of the past must be cleansed before society can stand on a rational and equitable footing.
From these rather abstract considerations, practical consequences follow. Because knowledge for the constrained vision is aggregated, individuals must be allowed choices to get right or wrong. Because, for the unconstrained vision, progress depends on the exertions of the rational elite, the government must be placed in its hands, and every restraint on its power will be an invitation to corruption and injustice. The many and the few -- personal sovereignty versus an all-knowing regulatory state -- Sowell's conflict of visions offers a clearer view of our moral and political reality than the eighteenth- and nineteenth-century concepts we habitually use.
It can also clarify today's policy battles. President Obama's health care legislation is predicated on the belief that a rational government should curtail the irrational choices of individual citizens, for the latter's own protection. Trade-offs of cost and choice are disdained. At present, with this smart and ambitious new administration, the unconstrained vision is triumphant.
In the matter of the accumulation of knowledge, the unconstrained vision solves the problem by denying its existence. On this account, the world Taleb described was illusory, not real -- a magician's trick pulled by self-interested parties to bilk the gullible public. There are no uncertainties, no denials of probability, no black swan events. Knowledge advances in lockstep with the progress of the most rational minds, who are never surprised, and for whom no problem, social or physical, is too complex to lack an articulated solution.
This approach to the problem of knowledge -- or rather, of ignorance -- is, to say the least, implausible. I don't know whether human ignorance reaches the catastrophic levels suggested by Taleb, or at what point randomness takes over from simple causation. Certainly, much research shows that human decision-making in difficult environments isn't nearly as foolish as might be predicted.
But the claims and pretensions of the rationalists have a hollow ring. Who belongs to their elite? Is it self-elected? If so, then they are no less self-interested than the greediest of human wolves. How can there be a single "rational" outcome to every social problem? The rationalists themselves have put forward many solutions over time and in different places. Plato's republic was an Athenian dream of Sparta; William Godwin's utilitarian utopia was a nonconformist dream of heaven on earth. It is never clear what the "rationalism" of the rationalists consists of. It isn't predictive, or particularly explanatory. It isn't mathematical. As I have written elsewhere, it often appears to be nothing more than an emotional cry for certainty: the very trap Taleb warns against.
For parallel reasons, I find the constrained vision to be an interesting account of how we can exist in Talebian uncertainty yet grow our store of knowledge. In fact, when describing the constrained vision, Sowell appears to foreshadow Taleb -- only with a cure:
In the contrained vision, any individual's own knowledge alone is grossly inadequate for social decision-making, and often even for his own personal decisions. A complex society and its progress are therefore possible only because of numerous social arrangements which transmit and coordinate knowledge from a tremendous range of contemporaries, as well as from the even more vast numbers of those from generations past. [. . .] In this vision, it is not simply that individual choose rationally what works from what does not work, but also -- and more fundamentally -- that the competition of institutions and whole societies leads to a general survival of more effective collections of cultural traits, even if neither the winners nor the losers rationally understand what was better or worse about one set or the other.
Experience is the test. That is true of our moral traditions, our politics, even of science. On the whole, and with many trade-offs, the latter succeed in making possible happiness, freedom, and the accumulation of knowledge by an organism often fooled by randomness and confused by complexity in any form.