There are many ways in which we seek to influence other people's beliefs. We might employ procedural reason and rational persuasion of course. We might try to formulate a cogent argument. Or we might try to shape the beliefs of others in other ways, by way of threats, brainwashing, peer pressure, and indoctrination (through endless repetition, etc.), for example.
As a philosopher, I value reason. Indeed, like most people nowadays, I consider the use of reason to shape the beliefs of others to be, on the whole, a good thing, and the use of techniques like threats, brainwashing, peer-pressure and indoctrination to be a bad thing. But why should reason be preferred to these other methods of shaping belief?
One important difference between using reason and those other methods is that threats, brainwashing, peer pressure, etc. can be just as effective employed to produce false beliefs as true ones. They are not truth-sensitive. Try using reason to influence the beliefs of others, on the other hand, and you will find that reason is a double-edged sword. It will not necessarily favour your beliefs over the beliefs of those whose minds you seek to change. Reason favours the truth. As a result of engaging in reasoned argument with your intellectual adversary, you may find your opponent can show that you are the one that is mistaken (this is a risk that some ‘educators’ are not prepared to take – in which case they are likely to find those other methods of shaping belief rather more attractive).
According to some, ‘reason’ is a term used to dignify what is, in reality, just another causal mechanism for influencing belief, alongside brainwashing and indoctrination. Reason is, in reality, just another form of power – of thought control. It is essentially as coercive and manipulative as any other mechanism.
But is this true? While it is true that a rational argument can, in a sense, ‘force’ a conclusion on us, the ‘force’ involved is normative, not causal. Let me explain.
Causal determination determines what will happen. For example, given the causal power of these rails to direct this train, the train will go to Oxford. Normative determination, on the other hand, determines not what will happen, but what ought to. It is a distinct category of determination.
A rational argument shows you what you ought to believe if you want to give your beliefs the best chance of being true. Take this valid deductive argument:
All men smell
John is a man
Therefore, John smells.
To recognise that this argument is valid is just to recognize that if you believe that all men smell, and that John is a man, then you ought to believe that John smells. But of course this argument doesn't causally compel you to accept that conclusion even if you do accept the premises. You're free to be irrational.
This isn't to deny that rational arguments have causal power. Of course they do. A good argument can have the power to change history (consider the arguments of the campaigner against slavery William Wilberforce). But when rational arguments have the causal power to shape people's thinking, they typically have it as a result of their having normative power. People change their opinions because they recognize the normative force of the argument.
Notice, by the way, that we can easily show that a rational argument doesn't have normative power simply by virtue of its having causal power to shape people's beliefs. The obvious counter-example is fallacious argument. A fallacious argument lacks normative power. But notice that, if the fallacy is seductive, it will still have considerable causal power to affect belief.
So rational arguments can and do have causal power. But that is not to say that rational argument is just another form of causal manipulation alongside e.g. threats, brainwashing, peer pressure, etc.
To sum up, we have seen that, when it comes to shaping belief, rational argument differs from these other methods in at least two important ways:
(i) reason is truth-sensitive (whereas purely causal mechanisms typically are not)
(ii) while rational arguments can be causally powerful, their causal power typically derives from their normative power – which is a distinct, non-causal form of ‘power’.
But perhaps we need to add a caveat. Suppose I just show you something directly. In good daylight, I just physically point your head in the direction of a tree. Given you are normally sighted, you will immediately come to believe there's a tree there. You do not reason your way to this belief. Just like a victim of brainwashing and/or overwhelming peer pressure, etc. you are causally compelled to hold it. Your belief is involuntarily produced by a causal mechanism – sight. Yet we would not ordinarily consider this to be a form of psychological manipulation – certainly not of an insidious sort, alongside the use of brainwashing, peer pressure, etc. Why not? Perhaps because, unlike these other causal methods, and like procedural reason, our perceptual faculties also tend to be truth-sensitive.
