What’s the opposite of substrate independence?

I suppose we could call it “substrate dependence” or “substrate linkage,” but this really isn’t about the term, it’s about the substance. As I recently noted, the idea of substrate independence is often invoked to indicate that it should be possible to construct a (proper) mind in silicon, though we’ve not yet figured out how to do it. I have my doubts, but who knows?

Substrate independence presupposes a fully explicit computational procedure, one whose structure is fully accessible to an external observer, one that can be constructed from the outside. The human mind, as I’ve argued, is constructed from the inside. I note as well that while digital computers recognize a distinction between addresses and content (data stored at an address), there’s no reason to think that such a distinction exists in natural nervous systems. Nor is there a distinction between memory units and processing units – something von Neumann recognized in Computers and the Brain. All neurons seem to be both processors and memory. And each neuron is a living agent.

What if all these things – built from the inside, no distinction between address and content, no distinction between memory and processing, living components – are necessary for the construction of a mind? Could they be realized in silicon, or some other inert substrate? That’s not at all obvious.