I didn't write what follows, but it is well worth reading. From C.S. Lewis' "God in the Dock"
We have recently “discovered that we exist” in two new senses. The Freudians have discovered that we exist as bundles of complexes. The Marxians have discovered that we exist as members of some economic class. In the old days it was supposed that if a thing seemed obviously true to a hundred men, then it was probably true in fact. Nowadays the Freudian will tell you to go and analyze the hundred: you will find that they all think Elizabeth [I] a great queen because they all have a mother-complex. Their thoughts are psychologically tainted at the source. And the Marxist will tell you to go and examine the economic interests of the hundred; you will find that they all think freedom a good thing because they are all members of the bourgeoisie whose prosperity is increased by a policy of laissez-faire. Their thoughts are “ideologically tainted” at the source.
Now this is obviously great fun; but it has not always been noticed that there is a bill to pay for it. There are two questions that people who say this kind of thing ought to be asked. The first is, are all thoughts thus tainted at the source, or only some? The second is, does the taint invalidate the tainted thought - in the sense of making it untrue - or not?
If they say that all thoughts are thus tainted, then, of course, we must remind them that Freudianism and Marxism are as much systems of thought as Christian theology or philosophical idealism. The Freudian and Marxian are in the same boat with all the rest of us, and cannot criticize us from outside. They have sawn off the branch they were sitting on. If, on the other hand, they say that the taint need not invalidate their thinking, then neither need it invalidate ours. In which case they have saved their own branch, but also saved ours along with it.
The only line they can really take is to say that some thoughts are tainted and others are not - which has the advantage (if Freudians and Marxians regard it as an advantage) of being what every sane man has always believed. But if that is so, we must then ask how you find out which are tainted and which are not. It is no earthly use saying that those are tainted which agree with the secret wishes of the thinker. Some of the things I should like to believe must in fact be true; it is impossible to arrange a universe which contradicts everyone’s wishes, in every respect, at every moment. Suppose I think, after doing my accounts, that I have a large balance at the bank. And suppose you want to find out whether this belief of mine is “wishful thinking.” You can never come to any conclusion by examining my psychological condition. Your only chance of finding out is to sit down and work through the sum yourself. When you have checked my figures, then, and then only, will you know whether I have that balance or not. If you find my arithmetic correct, then no amount of vapouring about my psychological condition can be anything but a waste of time. If you find my arithmetic wrong, then it may be relevant to explain psychologically how I came to be so bad at my arithmetic, and the doctrine of the concealed wish will become relevant - but only after you have yourself done the sum and discovered me to be wrong on purely arithmetical grounds. It is the same with all thinking and all systems of thought. If you try to find out which are tainted by speculating about the wishes of the thinkers, you are merely making a fool of yourself. You must find out on purely logical grounds which of them do, in fact, break down as arguments. Afterwards, if you like, go on and discover the psychological causes of the error.
In other words, you must show that a man is wrong before you start explaining why he is wrong. The modern method [Note: This essay was written in 1941.] is to assume without discussion that he is wrong and then distract his attention from this (the only real issue) by busily explaining how he became to be so silly. In the course of the last fifteen years I have found this vice so common that I have had to invent a name for it. I call it “Bulverism.” Some day I am going the write the biography of its imaginary inventor, Ezekiel Bulver, whose destiny was determined at the age of five when he heard his mother say to his father - who had been maintaining that two sides of a triangle were together greater than the third - “Oh, you say that because you are a man.” “At that moment,” E. Bulver assures us, “there flashed across my opening mind the great truth that refutation is no necessary part of argument. Assume your opponent is wrong, and then explain his error, and the world will be at your feet. Attempt to prove that he is wrong or (worse still) try to find out whether he is wrong or right, and the national dynamism of our age will thrust you to the wall.” That is how Bulver became one of the makers of the Twentieth Century.
I find the fruits of his discovery almost everywhere. Thus I see my religion dismissed on the grounds that “the comfortable parson had every reason for assuring the nineteenth century worker that poverty would be rewarded in another world.” Well, no doubt he had. On the assumption that Christianity is an error, I can see clearly enough that some people would still have a motive for inculcating it. I see it so easily that I can, of course, play the game the other way round, by saying that “the modern man has every reason for trying to convince himself that there are no eternal sanctions behind the morality he is rejecting.” For Bulverism is a truly democratic game in the sense that all can play it all day long, and that it give no unfair advantage to the small and offensive minority who reason. But of course it gets us not one inch nearer to deciding whether, as a matter of fact, the Christian religion is true or false. That question remains to be discussed on quite different grounds - a matter of philosophical and historical argument. However it were decided, the improper motives of some people, both for believing it and for disbelieving it, would remain just as they are.
I see Bulverism at work in every political argument. The capitalists must be bad economists because we know why they want capitalism, and equally Communists must be bad economists because we know why they want Communism. Thus, the Bulverists on both sides. In reality, of course, either the doctrines of the capitalists are false, or the doctrines of the Communists, or both; but you can only find out the rights and wrongs by reasoning - never by being rude about your opponent’s psychology.
Until Bulverism is crushed, reason can play no effective part in human affairs. Each side snatches it early as a weapon against the other; but between the two reason itself is discredited. And why should reason not be discredited? It would be easy, in answer, to point to the present state of the world, but the real answer is even more immediate. The forces discrediting reason, themselves depend of reasoning. You must reason even to Bulverize. You are trying to prove that all proofs are invalid. If you fail, you fail. If you succeed, then you fail even more - for the proof that all proofs are invalid must be invalid itself.
The alternative then is either sheer self-contradicting idiocy or else some tenacious belief in our power of reasoning, held in the teeth of all the evidence that Bulverists can bring for a “taint” in this or that human reasoner. I am ready to admit, if you like, that this tenacious belief has something transcendental or mystical about it. What then? Would you rather be a lunatic than a mystic?
So we see there is justification for holding on to our belief in Reason. But can this be done without theism? Does “I know” involve that God exists? Everything I know is an inference from sensation (except the present moment). All our knowledge of the universe beyond our immediate experiences depends on inferences from these experiences. If our inferences do not give a genuine insight into reality, then we can know nothing. A theory cannot be accepted if it does not allow our thinking to be a genuine insight, nor if the fact of our knowledge is not explicable in terms of that theory.
But our thoughts can only be accepted as a genuine insight under certain conditions. All beliefs have causes but a distinction must be drawn between (1) ordinary causes and (2) a special kind of cause called “a reason.” Causes are mindless events which can produce other results than belief. Reasons arise from axioms and inferences and affect only beliefs. Bulverism tries to show that the other man has causes and not reasons and that we have reasons and not causes. A belief which can be accounted for entirely in terms of causes is worthless. This principle must not be abandoned when we consider the beliefs which are the basis of others. Our knowledge depends on our certainty about axioms and inferences. If these are the results of causes, then there is no possibility of knowledge. Either we can know nothing or thought has reasons only, and no causes.