We have to take pains to stimulate and strengthen within us a mood that may be expressed as follows. It must be as though we were constantly saying to ourselves: I ought not to expect that my thinking can give me knowledge of the truth, I ought rather solely to expect of my thinking that it shall educate me. It is of the utmost importance that we should develop in us this idea, namely, that our thinking educates us. If you will really take this point of view as a practical rule of life you will find that there are many occasions when you are led to quite different conclusions from those that seem at first sight to be inevitable. […]

So long as one expects by thinking to come to conformity with some objective reality, so long as we give ourselves up to the belief that by thinking or by the elaboration of concepts or, let us say, by the elaboration in thought of experiences we have in the world, we can come to reality, so long are we indeed in desperate case, if someone comes forward and shows us that a particular statement and its exact opposite can equally well be proved. For if this is so, how are we ever to arrive at Truth?

If, however, we have learned that where the situation demands a decisive pronouncement, thinking can come to no conclusion about reality, if we have persistently educated ourselves instead to look upon thinking as a means to become wiser, as a means to take in hand our own self-education in wisdom, then it does not disturb us at all that at one time one thing can be proved and at another time its opposite can be proved. For we very soon make the following discovery. The fact that the elaboration of concepts does not, so to say, expose us in the least to the onset of reality, is the very reason why we are able to work with perfect freedom within the sphere of concepts and ideas and to carry on our own self-education by this means.

If we were perpetually being corrected by reality, then the elaboration of concepts would not afford us a means of educating ourselves in this manner in perfect freedom. I would like to ask you to give careful consideration to this fact. Let me repeat it. The elaboration of concepts affords us a means of effective and independent self-education, and it can only do so because we are never disturbed in the free elaboration of concepts by the interference of reality.

Source: Rudolf Steiner – GA 134 – The World of the Senses and the World of the Spirit: Lecture II – Hanover, 28th December 1911