Would you mind if I bundled together two comments? First one, why use a word like 'soul'? It carries a specific (although not entirely defined) supernatural meaning. When talking about soul, either one is defending a mystical dimension (a theological duality between matter and spirit), or he is referring to some sort of psychological phenomenon that could be much better addressed with non-mystical vocabulary. In my opinion, that is.

The second comment is that "spirit" has been used many times as a metaphor for psychological phenomena. Fichte, a follower of Kant, would say that spirit is our ability to come in touch with a higher inner dimension, a sort infinite within. Because some ideas, like freedom, can't be defined in words or explained as concepts, they must be understood first-hand by experience. Spirit, in this sense, isn't supernatural at all. It is our ability to sense and experience these ideas that cannot be contained in a concept.

To him, the spirits of two people can't touch each other directly (since they're processes, not things). But they can communicate through works of art. Great art carries a message beyond the physical medium which is very difficult to point out, but that can be sensed by the spirit of another, and his spirit would elevate him to the idea within himself. Such a work would seem to someone without spirit as a mere craft, but would be alive to someone with spirit.

In my opinion, that is an elegant postulation of how spirits could touch. I (greatly) dislike the use of the word, but I do think life can get much richer and deeper once we can connect to and cultivate or "spirits". Even more so once we abandon the illusion that life has a hidden supernatural dimension.

Sorry for the long answer to your great post. Keep'em coming!