According to Kant, to have a priori knowledge does not mean that we possess it before having sensory experience (i.e., as a set of inborn ideas); we find it within experience when we cease to be interested solely in its contents and turn − in the mode of reflection − our attention to its form. Then we find out that any further inter-subjectively valid experience cannot correct the a priori knowledge or even falsify it; it is because the a priori knowledge is a necessary presupposition of any inter-subjectively valid experience.#
If the functioning of human mind includes some kinds of necessary a priori relationalisations (such as the teleological order of thought, the principle of constantly operating causes, formal logic, universal grammar, etc.), and if human mind is a part of nature and stems from it, then nature, too, must contain some sorts of necessary relations and interconnections; namely, it is impossible that the necessity of mind’s functioning could stem from a fully contingent nature.#
Purposeful action arises when animal instrumental activities (as based on pre-conceptual gestalt relationalisations and confined to what is within the horizon of actual perception) becomes subordinated to language which, as being able to make present what in not present in sensory perception, orients them to the materialisation of something which is originally beyond that horizon.#