[js1138]

In reality, we can check the correspondence of our thought against the outside world, contradicting the above corollary of materialist philosophy.

You can do that if you start by assuming that your brain is not malfunctioning. But what if it is?

The people whose brains we think are malfunctioning don't think they are.

[DannyTN]

The people whose brains we think are malfunctioning don't think they are. - JS1138

His comment would appear to be self-evident.

[Aquinasfan]

You can do that if you start by assuming that your brain is not malfunctioning. But what if it is?

The people whose brains we think are malfunctioning don't think they are.

True. This is a very difficult case. I don't know the genesis of the problem of schizophrenia in general. Sense impressions are never false in themselves since sensation is an immanent activity (Whether there is falsity in the senses?). What is difficult to determine is the origin of the schizophrenic's apparent sensory perceptions. Is the schizophrenic truly hearing voices? This could be true in the case of possession diagnosed as schizophrenia. Is the sense of hearing defective? Do the voices originate in the imagination? I don't know. But at the very least, I would think that the schizophrenic would know that something is wrong with him, or know that most other people think so.

My original point was that materialist philosophy cannot provide a coherent account for the general reliability of our senses.