If you want to see a philosopher go about as disasterously wrong as possible on an important topic, check out Richard Sharvy from the the Journal of Libertarian Studies. His conclusion:
"If you want a house designed, consult a good architect, have plans drawn, and make your own decision. If you don’t like the plans, get a second opinion—from another professional architect. If you have a medical problem, see a physician for advice. If you don’t like his advice, get a second opinion—from another expert.
"Who’s to say what’s right and wrong about the strengths of bridge supports? A professional engineer. Who’s to say what medical treatment is right or wrong? A physician. Who’s to say what is morally or ethically right or wrong? A professional philosopher.
"It is outrageous that national commissions on 'ethics' and 'morality' often consist mostly of unqualified laymen: physicians, priests, lawyers, etc., rather than professional philosophers (see Singer 1976).
"Professional philosophers are the people who are experts on questions about what is right and wrong."
The confusion Sharvey exhibits is akin to that of someone whom, because he has a PhD in physics, is certain that he can crush Minnesota Fats at pool, or, because he has studied economics, believes he is a match for Warren Buffett at investing. The physicist is good at theorizing about physics, but Minnesota is good at applying it. If you want to understand the theory of sexual reproduction, you go to a genetic biologist. But is that who you're going to go to for advice on your sex life?!
The absurdity of Sharvey's claims becomes clear when one considers an "ethicist" whom Sharvey, in fact, cites, Peter Singer, a philosopher who is prone to offer advice about as destructive and un-ethical as you could hope to find on the planet. Sharvey would say, "Well, sure, but professional engineers sometimes disagree about bridges, as well." Yes, they do, but we never find a professional engineer telling us to build a bridge from methane gas, which would be about the equivalent of Singer's advice.
Michael Oakeshott was highly critical of theorists who made this error and therefore became despised "theoreticians." In On Human Conduct, which was published in 1975, he presents a dichotomy similar to his earlier contrasting of rationalism and traditionalism, but, in this instance, the distinction drawn is between the practitioner and the theorist. After a lengthy discussion of the nature of theorizing, he pauses to note the debt his analysis owes to the understanding offered by Plato, especially in the metaphor of the cave contained in The Republic. In light of the similarity of their views, Oakeshott continues, ‘it may be instructive to notice [their] divergencies’ (1975: 27).
As Oakeshott reads Plato, the cave-dwellers represent those whose attention is fixated on the world of practical affairs. Plato was correct, in Oakeshott’s view, when he contended that, because such individuals fail to recognize the conditional nature of their practical understanding of reality, they essentially are ‘prisoners’ of their limited perspective.
However, Oakeshott argues, ‘distracted by his exclusive concern with the engagement of theoretical understanding and with the manifest shortcomings of [the cave-dwellers world]… that he is disposed to write [the latter] of as nescience. This, I think, is a mistake’ (1975: 27). That the practical understanding of the world is inherently conditional does not negate the fact that it is nonetheless a genuine form of understanding, even if, given that it never questions its presuppositions, a form properly judged inferior to that achieved by the theorist. Moreover, most crucially for Oakeshott, the abstract superiority of theoretical knowledge over its practical counter-part in no way implies that the former can substitute for the latter. While it is true that discovering ‘that a platform of understanding is conditional and to become acquainted with its proximate conditions is a notable step in the engagement of understanding’, that discovery ‘is not like exposing a fraud… shadows are not forgeries’ (1975: 28).
Since knowledge of the realm of the shadows is a real and hard-won achievement, the theorist goes gravely astray when he erroneously attempts to use his insights to issue authoritative directives to the practitioner as to how to proceed in his mundane activities. The cave-dwellers, encountering him on his return to the practical world, might be impressed ‘when he tells them that what they had always thought of as “a horse” is not what they suppose it to be… but is, on the contrary, a modification of the attributes of God… But if he were to tell them that, in virtue of his more profound understanding of the nature of horses, he is a more expert horse-man, horse-chandler, or stable boy than they (in their ignorance) could ever hope to be, and when it becomes clear that his new learning has lost him the ability to tell one end of a horse from the other… Before long the more perceptive of the cave-dwellers would begin to suspect that, after all, he was not an interesting theorist but a fuddled and pretentious “theoretician” who should be sent on his travels again, or accommodated in a quiet home’ (1975: 30).
I suggest that this section of On Human Conduct provides a perspective on rationalism that, while different to that of Oakeshott’s earlier essays on the subject, is complementary rather than contradictory to its precursors. Here, the modern rationalist is understood as a ‘theoretician’ who is reiterating Plato’s ancient misstep. Because he justifiably conceives the theoretical understanding he has achieved to be, in some sense, superior to practical understanding, he mistakenly concludes that theory ought to be the unquestioned master of practice. He fails to realize that the fundamentally different concerns of theorizing render its findings intrinsically irrelevant to practical matters, unless they are translated from their native idiom into that of practice.