Material things and the real distinction between mind and body

Do material things exist?

I perceive them clearly as the subject matter of pure mathematics, and so they can exist.

Anything that I perceive in that way could only be created by God.

If something else created a thing not created by God, then that would be a contradiction in my perceiving it distinctly.

I use my imagination when I turn my mind to material things.

My imagination also suggests that they really exist.

How does imagination differ from pure understanding?

When I imagine a triangle I see its 3 lines with my mind’s eye as if they were present.

But if I think of a chiliagon (a shape with 1,000 sides), I do not imagine 1,000 sides.

This is because my imagination is incapable of creating a chiliagon.

Yet I understand what a chiliagon is.

Imagining Versus Understanding

Being able to understand is more essential than being able to imagine.

Even if I had no power of imagination, I would still be the same person.

This implies that my power of imagining depends on something other than myself.

If my body exists – that is, if my mind is joined to a body so that my mind can contemplate that body whenever it wants to – then it means that:

my body enables me to imagine physical things.
imagining differs from pure understanding in this way.

When the mind understands, it somehow:

turns in on itself and
inspects one of its own ideas.

But when the mind imagines, it:

turns away from itself and
looks at something in the body (something that conforms to an idea – either one understood by the mind or one perceived by the senses).

This might be how imagination comes about if the body exists.

Since there is no other way to explain what imagination is, I can conjecture that the body exists.

But this is only a probability.

Even after careful enquiry, I still cannot see how on the basis of the idea of physical nature, that my imagination proves that some body exists.

Physical nature is the subject-matter of pure mathematics.

I also imagine colours, sounds, tastes, pain and so on – though not so distinctly.

I perceive these much better through the senses, which is how (helped by memory) they reach my imagination.

This leads me to explain ‘sensory perception’.

I want to know whether the things that are perceived through the senses prove the existence of bodies.

External Bodies Exist Only In the Mind

1. Our ideas come from sensations

I perceive my head, hands, feet and other limbs making up my body through my senses.

My senses also perceive that this body is among many other bodies that could harm or help it.

I detected:

the favourable effects by a sensation of pleasure
the unfavourable ones by pain.

Aside from pain and pleasure, I also had sensations of:

hunger, thirst, and other such appetites, and
bodily states tending towards cheerfulness, sadness, anger and similar emotions.

Outside myself, besides the size [extension], shapes and movements of bodies, I also had sensations of:

their hardness and heat, and of the other qualities that can be known by touch.
light, colours, smells, tastes and sounds.

The differences amongst these enabled me to sort out the sky, the earth, the seas and other bodies from one another.

All of these perceptions were my ideas.

But they were from external bodies that created ideas through my senses.

These ideas came to me without my consent.

I could not have an idea of an object that I wanted if that object was not detected by my sense organs.

The ideas that came through my senses were much more lively, vivid and sharp than the ones in my imagination and my memory.

So it means that those sensory ideas were not coming from within me.

I conclude that they came from external things.

My only way of knowing about these things was through the ideas themselves, so it was bound to occur to me that the things might resemble the ideas.

It also means that used my senses even before I had the use of reason.

The ideas that I formed were mostly made up of elements of sensory ideas.

This convinced me that all my ideas came from sensations.

My body belongs to me in a way that no other body did.

There were 3 reasons for this.

I could never be separated from it, as I could from other bodies.
I felt all my appetites and emotions in it and because of it.
I was aware of pain and pleasurable ticklings in this body but not in any other body.

But why should that sensation of pain create a distress of mind?

Why should a kind of delight follow a tickling sensation?

Why does:

hunger tell me to eat?
thirst tell me to drink?

I could only explain it as nature teaching me so.

For there is no connection between:

hunger and the decision to eat
pain and the distress that it causes

Nature taught me to make these judgments about sensory objects before I had any arguments to support them.

2. Our Senses Can be Mistaken

Later on, however, my experiences gradually undermined my faith in my senses.

A tower that had looked round from a distance appeared square from close up.
An enormous statue standing on a high column didn’t look large from the ground.

In countless such cases, I found that the judgments of the external and internal senses were mistaken.

What can be more internal than pain?

Yet I heard that an amputee might occasionally seem to feel pain in the missing limb.

So even in my own case, I had to conclude, it was not certain that a particular limb was hurting, even if I felt pain in it.

I recently added 2 very general reasons for doubting:

Every sensory experience when awake can be had while asleep.

Whatever I perceive in sleep comes from within me.

Then why should I I didn’t see why I should be any more inclined to believe this of what I think I perceive while awake.

for all I knew to the contrary I might be so constituted that I am liable to error even in matters that seem to me most true.

I could not rule this out, because I did not know – or at least was pretending not to know – who made me.

And it was easy to refute the reasons for my earlier confidence about the truth of what I perceived by the senses.

Since I seemed to be naturally drawn towards many things that reason told me to avoid, I reckoned that I should not place much confidence in what I was taught by nature.

Also, I decided, the mere fact that the perceptions of the senses didn’t depend on my will was not enough to show that they came from outside me; for they might have been produced by some faculty of mine that I didn’t yet know.

3. I am not my body

But now, when I am beginning to know myself and my maker better, I can selectively accept my sensory perceptions.

Whenever I have a clear and distinct thought of something, it means that God created it in a way that exactly corresponds to my thought.

So the fact that I can clearly and distinctly think of one thing apart from another means that the 2 things are distinct.

They are separated by God.

Never mind how they could be separated.

That does not affect the judgment that they are distinct.

So my mind is a distinct thing from my body.

Furthermore, my mind is me because I know that:

I exist and
nothing else belongs to my nature or essence except me being a thinking thing

It follows that my essence consists solely in my being a thinking thing, even though there may be a body that is very closely joined to me.

I have a clear and distinct idea of:

myself as something that thinks and isn’t extended, and
my body as something that [has size] is extended and does not think.

It means that I am really distinct from my body and can exist without it.

I find that I am capable of certain special kinds of thinking, namely:

imagination and
sensory perception.

I can clearly and distinctly understand myself as a whole without these faculties.

But I cannot understand them without me, that is, without an intellectual substance for them to belong to.

A faculty or capacity essentially involves acts, so it involves some thing that acts.

So I see that I differ from my faculties as a thing differs from its properties.

There are other faculties – such as those of moving around, changing shape, and so on – which also need a substance to belong to.

But it must be a bodily or extended substance and not a thinking one, because those faculties essentially involve extension but not thought.

I have a passive faculty of sensory perception – an ability to receive and recognize ideas of perceptible objects.

But I would have no use for this unless something (myself or something else) had an active faculty for producing those ideas in the first place.

But this faculty cannot be in me, since:

it does not presuppose any thought on my part, and
sensory ideas are produced without my cooperation and often even against my will.