The classical liberal has an apparently ambiguous response to 'reason'. In a phrase, they are attracted to 'rationality' and repelled by 'rationalism'. But what does this contrast come down to? Liberals, I submit, differ from rationalists in that liberals see reason as a value, not as a power. Unlike rationalists, they do not see reason as a kind energy or motive force, to be unlocked and unleashed to perform marvels. In favouring a posture of cognitive humility, the liberal pins no great hopes on human reason. But, for all that, they believe reason exists, and is worth paying for when it is to be had. Why?
The liberal values reason because he believes that freedom cannot perform its economic feats without reason. The invisible hand's merit is not invincible to the merits of the choices that compose it. If you like, we need to know the quickest way to our workplace if the invisible hand is to secure what no planner could ever achieve: a maximising allocation of resources. But this valuation of reason is, it must be allowed, not a valuation of great reason. It is not a scintillating exercise of reason to know the shortest way to work, or home. A horse knows as much. Such mundane performances miss out on so much of the valuation of reason by liberals. Has not the cultivation of mind been a glory of liberal society? Are we to suppose this glory is merely an unbidden fruit of liberal values? Has not no small part of this glory been won by liberal thinkers, and their fellow travelers? Should we assume that their achievement was extraneous to their values?
In truth, it is not immediately clear whether liberal society should value the more refined productions of reason. The invisible hand - let it be stressed - does not require for its success that any one appreciate the invisible hand. It would work just as well if no one believed a word of Smith; or read of word of Smith; or if not a word of Smith had been written.The success of Smith’s Invisible Hand, then, doesn’t require the general public to be philosophers. Or anyone to be a philosopher. Granted: a belief in liberalism requires some 'philosophy': for liberalism is so paradoxical a doctrine that - like the heliocentric model - it is not clear that anyone would believe it without the harvest of sustained intellectual cultivation. But, for all that, liberalism to work doesn't require liberalism to be believed; no more than the circulation of blood requires belief in the circulation of blood.Granted: if the invisible hand was expressly disbelieved by the population then, doubtless, it would not be allowed to operate. Thus reasoning - superior reasoning - can obtain a value in correcting inferior reasoning, and the "Wealth of Nations" gains a value by discrediting "England's Treasure by Forraign Trade". Reason, then, can dispose of sophism.
For all that, in reading Smith we are still left with the thought that it would for the best if we didn't have any philosophers at all. Hayek seems to reinforce this thought by suggesting that social competition is sufficient to select in successful rules of behaviours. There is something odd in Hayek placing such confidence in such 'Darwinian' selection in the midst of the Age of Socialism, but the real defect in Hayek's position is that he istruncating the relation of freedom and reason. Yes, freedom facilitates reason - Hayek's position - but reason also facilitates freedom. Put simply: I can command you, or I can reason with you, (argue with you, discuss with you, etc). I can also seduce, convert you, you subvert you ; all these involve disregard for reason, and, I submit, a disregard for freedom. Reason, then, is the medium by which contrary wills may freely engage. It is the tournament that decides the conflict without resort to force.
This conception of reason's value lends itself to a certain understanding of political freedom that has proved popular with liberals; the 'Athenian' conception of democracy, or democracy-as-discussion. But it also obviously has an application to myriad bilateral relations between individuals.
Indeed, the conception of reason as the tiltyard of conflicting wills applies not just to a conflict of wills of different person, but to a clash of wills within the same individual. For one way the person who "does not know what to do" can solve that problem is by submitting to the will to others; to join a cult, or an army, or a totalitarian movement. Another way is to allow the victory of one part of their will over the other.To follow, for example, their "duty" in the face of a conflict of wills is to award dominion of one of their wills over the others. An alternative is for them to debate their motives for one action, or the other. This is surely makes for a freer action.
In championing reason as the medium by which contrary wills may freely engage, there is no assumption of the power of reason. There is no assumption that rational discussion will produce a political consensus, or even a decent majority. But it is through consensus we would like collective action to take place; and they would like such a consensus to be produced by rational deliberation.
The above brings also out that to liberals reason is 'a' value: it is not 'the' value. Liberals will not sacrifice freedom to reason. They will not support a dictatorship of scientists. Reason is valued as a complement to freedom. But at the same time freedom is a complement to reason, as Hayek rightly maintained. These twin stars orbit each other.