And by the way, all this works for your soul, too

Quotes from § 49, pp.84-86, ak.336-338:

...because objects which cannot be given us in any experience, do not exist for us...

However as the Ego in the proposition, "I am," means not only the object of internal intuition (in time), but the subject of consciousness, just as body means not only external intuition (in space), but the thing-in-itself, which is the basis of this phenomenon; [as this is the case] the question, whether bodies (as phenomena of the external sense) exist as bodies apart from my thoughts, may without any hesitation be denied in nature. But the question, whether I myself as a phenomenon of the internal sense (the soul according to empirical psychology) exist apart from my faculty of representation in time, is an exactly similar inquiry, and must likewise be answered in the negative.

And in a nearby footnote:

...the law of the permanence of substances has place for the purposes of existence only, and hence can hold good of things so far as they are to be consigned and conjoined with others in experience, but never independently of all possible experience, and consequently cannot hold good of the soul after death.

plus, in § 34:

...beyond [experience] no concepts have any significance, as there is no intuition that might offer them a foundation.

I have to take a break from reading to post about this, because this completely blew my mind.

So, okay, let's see here: objects exist, but we can't know anything about them-in-themselves. We can know about our experiences with them, and that is all we can know. Our sensibilities enable nature/the-totality-of-appearances. Our understandings / our a priori synthetic principles of possible experience enable experience itself in a way analogous to the way our minds 'create' space and time. So it ends up that every object that meaningfully exists can be experienced. Several parts of that are wrong, I'm sure, but is that it vaguely?

So Kant took all that, and then applied it to your mind.

This whole thing seems almost solipsistic, but without the self, somehow. This idea that we would not exist without being aware of oneself is fascinating and absolutely trippy. We are self-aware; we can observe ourselves, or in other words experience ourselves, and so we exist. But things which cannot be experienced make no impression on any sensibility; how could one suppose something like that to exist in any meaningful sense?

How does this connect to Rousseau, and what it means to be human? For Rousseau, humans are self-aware creatures, who think, who consider events in sequence, who place artificial systems of value over otherwise equivalent things (cf. the dancer segment). There was a sense in Rousseau that we were over ourselves, disconnected from ourselves. Here in Kant, the "ego" wouldn't even exist if we weren't sensing it! I just remember that passage in Rousseau, where the savage dies without even noticing that he had been alive. In Kant's philosophy, where existence itself seems so deeply and meaningfully engraved in the geography of the human mind, it would make sense that existence itself would depend on self-awareness. What are the implications of this?

I apologize in advance if any of this turns out to be invalidated in what I haven't read yet. I'll edit if necessary.