quickly wrote:
In the Treatise, Hume is abundantly clear on the following point: objects are given by the imagination as a resolution to contradictions between the manner in which different faculties are presented with and reason about sensations. An object (for instance, a cup) is a collection of impressions, but is given substantial unity by the imagination; space and time are inferences, etc., etc. What seems lost is this notion that the Humean man wanders through a hallucinatory dream: rather, the Humean subject provides unity, prior to his actual experience of objects, to impressions, and as such, has a transcendental but non-Kantian ground for experience.

It seems Kant perhaps took more from Hume than I had realized. Can I interpret Hume as the "original transcendental idealist"? The original Kantian psychonaut, tunneling through experience to find that which must occur before the sentient experience?

Just a thought. But an interesting interpretive line.

Hume's "habits and customs of mind" apparently were transformed by Kant into a platonic apparatus of "categories and transcendental ego" but, I think, moreso anticipated Wittgenstein's "grammar and forms of life". I'd answer your question "no", however, leaving that distinction to Kant since Hume is not making a transcendental argument that entails 'foundationalism' of any kind. Hume's skepticism (e.g. problem of induction) is a consequence of a lack of any foundation for, or in, experience, which Kant found problematic. and sought to solve transcendentally.

[Hume] concluded that reason completely and fully deceives herself with this concept, talksely taking it for her own child, when it is really nothing but a bastard of the imagination, which, impregnated by experience, and having brought certain representations under the law of association, passes off the resulting subjective necessity (i.e., habit) for an objective necessity (from insight).

The process, however, is not transcendental in the kantian sense, because Hume is not saying what is it that allows such unity. The closest that Hume comes to saying something similar to a "condition" is his habituation response to the induction problem. But that is not a cognitive reply, much less transcendental. It's pure psychology in its earliest form.