“They say, namely, that what the mind can sense and in many ways perceive is not the mind itself nor existing things but only things that are neither in themselves or in any place; which means that the mind solely by its own power can create sensations and ideas which are not of real things. This amounts to regarding the mind partially as God. They say further that we, or our minds, have a freedom of such a kind that we constrain ourselves, that is, our minds, and indeed our very freedom. For after having contrived some fiction and given it its assent, the mind can no longer conceive or fashion it in any other way, and it is also forced by its fiction to conceive of other things in the same manner in order not to oppose the original fiction....”

Baruch Spinoza, On the Correction of Understanding