[mrob]

For the sake of argument, "spiritual" could be a class of physical objects that can only be produced by other spiritual objects. This is the old "vitalism" argument, which is generally considered discredited, but as the "hard problem of consciousness" is still unanswered, this is a small loophole that proponents can use to hang on to it.

[TimTheTinker]

I don't subscribe to the "vitalism" argument. I am only equipped to assert that "spiritual" (as opposed to physical) primarily constitutes the use of language as a form of unique self-expression. It can be imitated in machines, but never duplicated.

(There's a good reason the Turing test involves language, and that computers can't form meaningful intent on their own.)

I don't know enough to extend the definition any further, though I'm sure it's not limited to merely that.

[mrob]

As far as we know, human language is generated by the brain, and the brain is made of parts that can in principle be simulated. If other parts of the body also turn out to be essential, there's no known physical limitation on simulating those either. This doesn't mean it will actually be practicable to do so, only that it's not theoretically impossible. By what mechanism does your idea of "spirituality" make it impossible to simulate human brains with sufficient accuracy to pass a Turing test? (or any other language generator not necessarily modeled on humans)