© Michael Lacewing

Dif ficulties with idealism

This handout follows the handout on ‘Idealism’. You should read that handout first.

In the handout on idealism, we saw how idealism can emerge from the problems of
realism, indeed Berkeley argues, from commonsense. But it is no improvement on
realism if it faces objections that are just as powerful as those facing realism.

IS REALISM A SIMPLER ALTERNATIVE TO IDEALISM?

First, what causes perceptions? Without physical objects, what explains why we perceive
what we do? There are three options: ideas, my mind, and another mind. But ideas
themselves don’t cause anything, says Berkeley, they are completely passive. Second,
perception is quite different to imagining; we are more passive – the sensations just occur
to us, and we can’t control them. From this difference between (voluntary) imagination
and (involuntary) perception, we can rule out my mind. So they must be caused by
another mind. When you think of the complexity and systematicity of our perceptions,
Berkeley argues, that mind must be God.

If this seems ad hoc, Berkeley argues that it is at least no worse than invoking physical
objects. Realism claims to be able explain perception by appealing to something outside
our minds, physical objects, that cause our experiences. But Berkeley argues that physical
objects provide no explanation at all. No one has been able to say how it is that physical
objects give rise to ideas (even if we can say now how physical objects affect processes in
the brain, we still have no explanation of how any of this causes an experience). So how
our experiences come about remains a mystery.

A second objection: if ordinary (‘physical’) objects are really ideas, how can I distinguish
between my ‘ideas’, just part of my mind, and ‘real things’, part of the world beyond my
mind? Berkeley replies by again pointing out the distinction between perception and
imagination. In fact, Berkeley has three criteria for an idea being (part of) an object of
perception, rather than just my mind: the idea is not voluntary; the idea forms part of the
order of nature, the coherent set of ideas that we experience as reality; and the idea is
caused by (or part of – see below) the mind of God.

Developing the objection

This reply is consistent, but we may still not think that Berkeley’s position is not really
plausible. The hypothesis that there are physical objects that are independent of our
mind seems simpler than the claim that God causes our perceptions. It explains the
passivity of perception, the distinction between an idea in my mind and what is real, the
nature of illusions and mistakes, the continued existence of physical objects when we
aren’t perceiving them, all very well. And we can challenge Berkeley’s claim that
empiricism leads to idealism: arguably, we do experience physical objects – either directly
or via representations – but we certainly have no sensory experience of God.
To press the point, think about scientific investigation of physical objects. For instance,
when we open up the body of an animal, we discover – we see for the first time – its
heart, lungs, stomach and so on. Did they not exist before we saw them? If they didn’t,
how did the animal pump blood, breathe, or digest food?! But if they did exist, is that
because God perceived them? No, says Berkeley: What we perceive is what God wills us
to perceive.

Furthermore, Berkeley says that ideas can’t cause anything – and the heart, lungs,
stomach are collections of ideas. If physical objects are ideas, and ideas don’t cause
anything, then physical objects don’t cause anything. So the animal’s organs don’t cause it
to stay alive. Instead, Berkeley says, it is only minds that cause things – so everything in
the natural world is actually caused by God. Of course, we can say that the heart pumps
blood or the stomach digests food – but it is not strictly true. We should ‘think with the
learned, and speak with the vulgar’. Science therefore doesn’t discover causal relations; it
only discovers regularities, such as – if you open up an animal, you will discover its
organs; an animal whose organs don’t work dies; and so on.

Again, we can object that this shows that idealism is a much more complicated account
of perception than realism.

ILLUSIONS
Berkeley has argued that we can tell the difference between imagination and perception
by voluntariness and regularity. But what about misperceptions and illusions?
Misperceptions are no more voluntary than perceptions, and can be perfectly regular and
natural: a stick looks bent half-submerged in water, red looks grey under yellow light, and
so on. Is the stick both bent and not bent?? Berkeley’s response is that we aren’t
misperceiving – the stick is bent when half-submerged. However, this is misleading if we
infer that the stick would be bent when pulled out of the water. So we shouldn’t say ‘the
stick is bent’, since this means it would remain so under normal conditions; the intuitive
thing to say is that ‘the stick looks bent’ – and this is correct, it does look bent.

A CONFUSION ABOUT ‘IDEAS’

It can be easy to think that idealism entails that physical objects are completely
subjective, i.e. that they depend on our perceiving them to exist at all. After all, if they
are ideas, and ideas don’t exist except in minds, then physical objects must depend on
our minds to exist. But this doesn’t follow: Berkeley is a ‘realist’ about ideas of physical
objects, in this sense: the ideas that make up physical objects are independent of our
minds – we can’t imagine up a physical object or change its properties by will. So
although they are composed of ideas, they are just as independent of our minds as if they
were mind-independent in the way that direct and representative realists say they are.
Yet, as ideas, they depend on a mind. But it is not our minds they depend on, it is God’s.

But can Berkeley make this reply? A final objection to Berkeley’s idealism is that it is
confused in its use of ‘ideas’, at least when it comes to saying whether something is the
‘same’ idea or not. The objection goes like this:
1. Ideas exist in the mind.
2. So when I perceive the table, the ideas I perceive (which comprise the table) exist in
my mind. They are, after all, my perceptions.
3. But that means the table I perceive must exist in my mind.
4. You cannot experience my ideas. So you cannot see the very same table I see.
5. At best, you will experience a similar table, perhaps even an exact twin. While you
might see something qualitatively identical, you won’t see the numerically identical
table.

Berkeley replies that we see the same table in the sense of ‘exactly resembling’. We might
say, likewise, that if you and I both think of ice cream, we have the same idea. But, of
course, there are two ideas in this case – one that exists in your mind, and one that exists
in my mind. ‘The same idea’ is used ambiguously (with more than one meaning), because
we can count ideas by their content (‘table’, ‘ice cream’) or we can count them by whose
idea it is (your thought of ice cream, my thought of ice cream).

But this reply runs counter to commonsense. Surely you and I can look at the same
(numerically the same) table. Realism, of course, says we can; the table is a physical
object, publicly accessible, and independent of either of our minds.

Berkeley then has a further, two-part response: first, representative realism faces the
same problem – you experience your sense-data of the table, I experience mine, so we
don’t experience the same thing. But representative realism can say that we do, viz. we
both experience one and the same table via our different sense-data. But then Berkeley
says, he can say the same regarding the idea of the table in God’s mind; we both
experience the table that is in or caused by God’s mind.

However, this causes a further problem: how can the ideas that I perceive when I
perceive the table exist both in God’s mind and in mine? They must exist in mine
because I am perceiving them. So all we can say is that my ideas resemble God’s. But, in
fact, we saw the problem that ideas of physical objects don’t exist in God’s mind in
anything like the way they exist in mine. The solution was that God wills me to
experience the ideas of the table. But then if God wills you to experience them as well,
once again, we don’t perceive the very same table (set of ideas), but each perceive the set
of ideas God wills us to perceive.