But souls? How do you prove souls exist? — Corvus

I don't think souls/spirit are real distinct beings. We apply those terms to the nonphysical, 'mental' processes which ultimately cause/include the illusion of being, although they are actually fleeting and empty processes.

But when we go on to speak of non-linguistic thought, here we are really lost and have been for thousands of years. — Manuel

Perhaps it is our own definitions creating obstacles to further "discovery." Take non linguistic thought. I might argue that even the seemingly nonlinguistic, is linguistics, if the latter has as its common feature a Signifier/Signified, ie. 'meaning-construction' function. What nonlinguistic thought is not yet, primarily about meaning?