Below is an interesting paragraph I jotted down a few years ago from a book called The Mind and the Brain.
It’s dense but makes a really good argument against materialism. Materialism is the view that only matter exists, and thus people do not have souls (OK, I grant that no materialist would put it that way, but that’s what it amounts to!), or that the soul is merely produced by the body and is not a non-material component of our being in its own right. Here’s the paragraph (which I’ve divided up):
But if you equate the sequential activation of neurons in the visual pathway, say, with the perception of a color, you quickly encounter two mysteries. [In other words, if you think that the perception of color can be fully explained simply by physical processes in the brain, you encounter two big problems.]
The first is …that just as the human brain is capable of differentiating light from dark, so is a photo diode. Just as the brain is capable of differentiating colors, so is a camera. It isn’t hard to rig up a photo diode to emit a beep when it detects light, or a camera to chirp when it detects red. In both cases, a simple physical device is registering the same perception as a human brain and is announcing that perception.
Yet neither device is conscious of light or color, and neither would become so no matter how sophisticated a computer we rigged it up to. There is a difference between a programmed, deterministic mechanical response and the mental process we call consciousness. Consciousness is more than perceiving and knowing; it is knowing that you know. (25-26).
And here’s a good quote on how materialism would necessitate that we abandon any conception of moral accountability:
[materialism] reduces human beings to automatons. If all of the body and brain can be completely described without invoking anything so empyreal as a mind, let alone a consciousness, then the notion that a person is morally responsible for his actions appears quaint, if not scientifically naïve. A machine cannot be held responsible for its actions. If our minds are impotent to affect our behavior, then surely we are no more responsible for our actions than a robot is. It is an understatement to note that the triumph of materialism, as applied to questions of mind and brain, therefore makes people squirm. (52)