We have, therefore, no idea of a substance.
Inhesion in something is supposed to be requisite to support the existence of our perceptions.

Nothing appears requisite to support the existence of a perception.

We have, therefore, no idea of inhesion.

What possibility then of answering that question, Whether perceptions inhere in a material or immaterial substance, when we do not so much as understand the meaning of the question?
There is one argument commonly employed for the immateriality of the soul, which seems to me remarkable.

Whatever is extended consists of parts; and whatever consists of parts is divisible, if not in reality, at least in the imagination.