From the second and third acts of reason:
We can give an account of how long it takes a neuron to fire or an oak tree to grow or a weasel to run up a drainpipe, but not how long modus tollens or the Pythagorean theorem takes.
If we isolate discrete steps of a physical process, at the moment of an earlier one we can always stop a later one. There are infinite ways to keep a conclusion from being printed after one’s printed the premises. But what applies to printing cannot be said of the logic, even though we can clearly isolate discrete steps in it.
From the first act of reason/ intelligence, (and maybe) sensation
What is physically present within us cannot be physically outside of us. But some things in our consciousness are physically outside of us. Therefore,* some things in our consciousness are not physically present within us.
I include the “and maybe” because Early Modern philosophy discovered many problems with trying to extend this last claim to sensation. The sense object is always to some extent subjective, and we have no way of knowing to what extent this is so. Intelligence transcends this problem at least with its notion of being and object, which are necessarily other from subjects even if we go so far as to deny them anything but a purely formal content.
To the extent that our knowledge is implicated in sensation, we will be hard pressed to identify any non-materiality in it, and the better research program will always take its point of departure from the study of physical processes. No one has ever said that man was more than a first step outside of materiality.
*Look kids, a FESTINO in the wild!