A mind is a thing. An object.
— Bartricks
Don't think that can be right.
Objects tend to be breakable (under conservation), whereas things associated with mind are interruptible (experiences, thinking, etc).
So, processes, occurrences, though maybe memory is an exception.
The quote looks like a category mistake, and that's going by evidence mind you. — jorndoe
No, ironically it is you who is making the category error. Mental states are states. A state is a state of a thing. Just as water is sometimes in a fluid state, minds are in mental states. (Water can be solid, gas, or fluid; minds can be thinking, hoping, intending, desiring and so on).
It is a category error to confuse a state of a thing with the thing itself. This category error is extraordinarily common when it comes to the mind, as there is a tendency to use 'mind' and 'consciousness' interchangeably, even though minds are objects and consciousness is a state (a state of mind, with 'mind' being the thing that consciousness is a state of). This error is facilitated to some extent, no doubt, by the tendency to confuse the 'is' of predication with the 'is' of identity ('my mind is conscious' does not mean that my mind is consciousness, but rather that my mind is in a conscious state).
Anyway, an 'object' is a bearer of properties. That's a non-question begging definition. That is, it is a definition that doesn't just assume that all objects are material.
Exactly what properties are definitive of a material object is a matter of debate, but I will follow Descartes in holding that the defining property of a 'material' object is 'extension'. That is, it takes up some space (and by virtue of this there will be a boundary between the space it occupies and that which it doesn't, and that boundary will describe its shape).
When it comes to minds, their defining state seems to be consciousness. This is not to say that minds are always conscious (although that is what Descartes thought). But rather, that if an object is in a state of consciousness, then it qualifies as a mind by dint of that.
There's a big philosophical question over whether consciousness is a state of material objects. If it is, then minds are, or can be, material. But they'd still be objects, it is just that the objects in question would be composed of matter (our brain being the most likely candidate). So there isn't a debate over whether minds are objects; the debate is over what kind of objects they are or can be.
If consciousness is not a state of material objects - and again, I follow Descartes, Plato, Berkeley, Locke and plenty of others in holding that it is not - then minds are not material. They are objects; they bear properties (one being the property of consciousness), but they do not have the kinds of properties that material objects have (extension, shape, size, location, colour).
You must not, then, beg the question by simply assuming - as so many do nowadays - that all objects are material. There is nothing in the concept of an object that requires it to be material.
And if one follows Reason diligently - as diligently as Plato, Descartes, Berkeley and others did - one will arrive, as they did, at the conclusion that the mind is an immaterial object. (And of course, now - as ever - most people couldn't give a rat's arse what Reason says about the nature of reality, preferring to listen to themselves in one form or another).
One route to this conclusion (and there are lots) is via free will. We obviously do have free will. Any decision I make was made freely, even if the circumstances under which I made it were not under my control. For it was 'my' decision - my response to the situation. But of course, that would be an absurd contention if I myself was the product of alien forces. To hold myself morally responsible for my decisions but not for my circumstances would just be arbitrary. But it is not arbitrary. To hold oneself morally responsible for one's decision is rational; but to hold oneself morally responsible for one's circumstances is irrational. So, as it is rational to hold myself morally responsible for my decisions - something that would only be rational if I was free in respect of them - my reason is thereby telling me that I, the producer of those decisions, am not a product of alien forces. For if i have free will but would not have it if I was the product of alien forces, then I can conclude that I am not the product of alien forces.
Yet all material objects seem to be the product of alien forces, including - obviously - my body and its brain. Thus, I can conclude that as I have free will and am therefore 'not' a product of alien forces but a source of origination, then I am not a material object. (Which should have been obvious anyway - I 'have' a body, but I am not my body; I 'have' a brain, but I am not my brain and so on; my body is my body because I am in it, not becuase I 'am' it).
Obviously this argument - deductively valid and apparently sound though it is - will not move those who have already decided that everything that exists is material, and thus that free will, if it exists, has to be made sense of in material terms. But then those people are just dogmatists and their views about free will patently absurd.