Does Transcendental idealism really imply the concept of noumena? second hand accounts — sime
There's your problem!
I ought to read CPR — sime
Yes.
Is the noumena deduced? — sime
You mean the noumenon here. Noumena is plural. Kant ambiguously tends to conflate the noumenon with the thing-in-itself. If we assume he meant them synonymously, then he starts with the existence of things, which are presented to the understanding by means of sense perception. What we know of things, therefore, is how they appear to us by means of the forms of the understanding (the twelve categories), not what they are or may be in themselves, a part from said forms. On the one world interpretation (which is more tenable than the two world, in my opinion), there is one object which has two aspects, that which we see when the object is cognized, and that which we do not see, which is what the object is when not cognized.
Is the noumena inferred through logical induction as a necessary but unknowable transcendental cause? I can't see how, because I understand that for Kant, causation is a category of understanding for relating empirical observations. — sime
I think this is more or less it. The uncharitable reader would say that he has contradicted himself in referring to the noumenon causing the appearance, and there are plenty of passages that damn him in this regard. However, the more charitable reader can find other passages wherein Kant seems to be saying that we are obliged to think of the noumenon causing the presentation simply because causality is an a priori concept, and so gets applied to everything. It is not a causal relation in reality, but we are forced to
think of it in causal terms because we cannot but do so.
In other words, the conclusion of transcendental idealism given its stated premises, seems to be neither ontological nor epistemological. The conclusion cannot be a positive assertion of mind-dependent knowledge and phenomena on an empirical level of appearances on the one hand, and of an unknowable reality of "things as they are in themselves" on some 'transcendental' level. Neither can the conclusion be merely epistemological in still accepting the conceivability of noumena but denying knowledge of its nature or existence. — sime
Here's where perhaps the ethical comes in to address your concern. Kant speaks of the intelligible and empirical character, the former being one's noumenal self and the latter the subject of knowing. In other words, do not forget that you
are the noumenon and so are the ground of all acting. This is necessary to posit to account for freedom.