New Essay Volume 3

Appendix 5. (1133)

[Subjective truth and critical philosophy]

The same argument applies to the subjective truth of Protagoras and Kant, because in the system of subjective truth doubt is essential. The sceptic says that the human being can know nothing about things as they are in themselves; only subjective appearances are known. But this teaching, if not true in itself, must be subjective, granted that scepticism is to be coherent with itself. I no longer know whether the teaching of subjective truth is real; I can only say that it seems so to me subjectively. It is not sufficient to say that the teaching of subjective truth is itself subjective. I would have to say that I pronounce the teaching of subjective truth to be subjective only by means of a judgment which itself is subjective. But if no other truth exists for me, I know only with subjective, not absolute truth.

We can easily see that such a system keeps us always da capo listening to an endless refrain.

Let us apply this general reasoning to some particular proposition of critical philosophy. Critical philosophy admits subjective forms, which makes all human knowledge subjective. But its sole argument for proving the existence of these forms must be the principle of cause. It sees that human knowledge lies within a few supreme classes, and concludes that to produce this effect there must be in our spirit an equal number of causes which determine our knowledge in this way. I call these causes 'forms'. However, the only meaning that 'principle of cause' has in critical philosophy is subjective; it is itself a form of the intellect. Kant concluded that in the human spirit there are forms which make knowledge subjective, and built his whole theory upon them. Consequently, by presupposing them, he entered a vicious circle. He deduced the sources of subjectivity of acts of knowledge (forms) from one of the sources of subjectivity itself, that is, from a form: he proves the form by means of presupposed forms.
A similar objection was levelled at Kant in Germany by the fine author of Aenesidemus.