Humean ‘original existences’ and the inertia of reason
We are at last in a position to see something of the real shape and extent of the task of reconciliation that faces anyone striving to be true to everything Hume says. It is not, as we can now see, just a matter of interpreting reason’s inertia so as to preserve the sharp contrast with desire, as an ‘active’ force. That would be relatively simple. But this inertia must somehow also incorporate the idea of reason’s having a causal role comparable to, if qualitatively different from, desire’s. If that weren’t enough, it now turns out that this role is not even to be restricted to providing information about means, or even to producing the relevant secondary desire, but involves the capacity to engender (and extinguish) primary desires themselves.