4 The error of imaginary causes. To begin with dreams: ex post facto, a cause is slipped under a particular sensation (for example, one following a far-off cannon shot)--often a whole little novel in which the dreamer turns up as the protagonist. The sensation endures meanwhile in a kind of resonance: it waits, as it were, until the causal instinct permits it to step into the foreground--now no longer as a chance occurrence, but as "meaning." The cannon shot appears in a causal mode, in an apparent reversal of time. What is really later, the motivation, is experienced first--often with a hundred details which pass like lightning and the shot follows. What has happened? The representations which were produced by a certain state have been misunderstood as its causes.
In fact, we do the same thing when awake. Most of our general feelings--every kind of inhibition, pressure, tension, and explosion in the play and counterplay of our organs, and particularly the state of the nervus sympaticus--excite our causal instinct: we want to have a reason for feeling this way or that--for feeling bad or for feeling good. We are never satisfied merely to state the fact that we feel this way or that: we admit this fact only--become conscious of it only--when we have furnished some kind of motivation. Memory, which swings into action in such cases, unknown to us, brings up earlier states of the same kind, together with the causal interpretations associated with them--not their real causes. The faith, to be sure, that such representations, such accompanying conscious processes are the causes is also brought forth by memory. Thus originates a habitual acceptance of a particular causal interpretation, which, as a matter of fact, inhibits any investigation into the real cause--even precludes it.
5 The psychological explanation of this. To derive something unknown from something familiar relieves, comforts, and satisfies, besides giving a feeling of power. With the unknown, one is confronted with danger, discomfort, and care; the first instinct is to abolish these painful states. First principle: any explanation is better than none. Since at bottom it is merely a matter of wishing to be rid of oppressive representations, one is not too particular about the means of getting rid of them: the first representation that explains the unknown as familiar feels so good that one "considers it true." The proof of pleasure ("of strength") as a criterion of truth.
The causal instinct is thus conditional upon, and excited by, the feeling of fear. The "why?" shall, if at all possible, not give the cause for its own sake so much as for a particular kind of cause--a cause that is comforting, liberating, and relieving. That it is something already familiar, experienced, and inscribed in the memory, which is posited as a cause, that is the first consequence of this need. That which is new and strange and has not been experienced before, is excluded as a cause. Thus one searches not only for some kind of explanation to serve as a cause, but for a particularly selected and preferred kind of explanation--that which has most quickly and most frequently abolished the feeling of the strange, new, and hitherto unexperienced: the most habitual explanations. Consequence: one kind of positing of causes predominates more and more, is concentrated into a system and finally emerges as dominant, that is, as simply precluding other causes and explanations. The banker immediately thinks of "business," the Christian of "sin," and the girl of her love.
--Nietzsche, "Twilight of the Idols"