Think: A Compelling Introduction to Philosophy

by Simon Blackburn

‘there is not one of my former beliefs about which a doubt may not properly be raised’.

I now know that even bodies are not strictly perceived by the senses or the faculty of imagination but by the intellect alone, and that this perception derives not from their being touched or seen but from their being understood; and in view of this I know plainly that I can achieve an easier and more evident perception of my own mind than of anything else.

there is something troubling about the idea that all experience might be a dream. For how could we set about determining whether that is true? Sometimes people ‘pinch themselves’ to ensure that they are not dreaming. But is this really a good test? Might we not just dream that the pinch hurts? We might try from within a dream to discover whether it is a dream. Yet even if we think up some cunning experiment to determine whether it is, might we not just dream that we conduct it, or dream that it tells us the

answer that we are awake?

His project was to deceive me about everything. But it is not logically possible for him to deceive me into thinking that I exist when I do not.

I cannot doubt that I exist. I can doubt whether things extended in space (‘bodies’) exist. Therefore, I am not a body. In a nutshell, souls are certain, bodies

he is suggesting that the senses are like messengers that deliver information that needs interpreting.

we understand by the self, the ‘I’, just some equally elusive ‘thing’ that at different times thinks different thoughts.

if only we could see the rest of reality, mind, body, God, freedom, human life, with the same rush of clarity and understanding! Well, one philosophical ideal is that we can. This is the ideal of rationalism: the power of pure unaided reason. For the rationalist can see from her armchair that things must be one way and cannot be other ways, like the angle in the semicircle. Knowledge achieved by this kind of rational insight is known as ‘a priori’:

Descartes discovers that he has an idea of perfection. He then argues that such an idea implies a cause. However, the thing that caused it must have as much ‘reality’, and that includes perfection, as the idea itself. This implies that only a perfect cause, that is, God, will do. Hence God exists, and has left the idea of perfection as an innate sign of his workmanship in our minds, like a craftsman leaving a trademark stamped in his work.

For since God is perfect, he is no deceiver: deceiving is clearly falling short of goodness, let alone perfection. Hence, if we do our stuff properly, we can be sure that we will not be the victims of illusion. The world will be as we understand it to be. Doing our stuff properly mainly means trusting only clear and distinct ideas.

we can only touch God’s supposed qualities by way of definition, but cannot comprehend them. In that case we cannot argue back to an ideal or archetype that enabled us to comprehend them.

this principle about causation is scarcely demon-proof. In fact, it is not even true. We have become familiar with causes that bear no resemblance to their effects.

Then the circle is that at some points it seems that Descartes holds: I can know that (CDp → Tp) only if I first know G. But at other points he holds: I can know that G only if I first know (CDp → Tp).

It recommends an universal doubt, not only of all our former opinions and principles, but also of our very faculties; of whose veracity, say they, we must assure ourselves, by a chain of reasoning, deduced from some original principle, which cannot possibly be fallacious or deceitful.

The self-corrective nature of our systems of belief, mentioned above, is all we need. We could call this approach non-rational or natural foun-dationalism.

Their paradigm was knowledge by sense experience rather than by reason. Because of this, they are labelled empiricists, whereas Descartes is a card-carrying rationalist.

it will take an act of faith to settle it.

‘God’ simply labels whatever it is that ensures this harmony between belief and the world. But, as Hume says in the passage just quoted, we do not find a need to raise this question in normal life. The hyperbolic doubt, and the answer to it, is in this sense unreal.

We are like sailors who on the open sea must reconstruct their ship but are never able to start afresh from the bottom.

This approach is usually called ‘coherentism’. Its motto is that while every argument needs premises, there is nothing that is the premise of every argument. There is no foundation on which everything rests.

It is good, then, to remember four options in epistemology (the theory of knowledge). There is rational foundationalism, as attempted by Descartes. There is natural foundationalism, as attempted in Hume. There is coherentism. And brooding over all of them, there is scepticism, or the view that there is no knowledge.

science tells us that ‘low-entropy’ or, in other words, highly ordered systems are more improbable. In addition, as physical systems like the cosmos evolve, entropy or disorder increases.

Similarly, the argument goes, it is as if God or Nature had less to do, to make the world as it is today out of nothing, than to make the lower-entropy world as it is supposed to have been some thirteen billion years ago out of nothing. Therefore, it is more probable that it happened like that.

Any confidence in a harmony between the way we take things to be, and the way they are, will seem to be a pure act of faith.

They also belong to a distinct kind of substance—immaterial substance—a kind of ghost-stuff or ectoplasm. Strictly speaking if I say, ‘I’ thought of the Queen and I saluted,’ there is a kind of ambiguity: the ‘I’ that is the subject of the thought is not the ‘I’, the body, that salutes. Thoughts and experiences are modifications in one kind of stuff; movement and position belongs to the other. This part of Descartes’s doctrine marks him as a ‘substance dualist’. It is not just that there are two kinds of properties (mental properties and physical properties) and that persons can have both. It is that there are two kinds of bearers of properties as well.

People who hold that there are two kinds of property (mental and physical) but that they can belong to the one kind of stuff (whatever large animals are made of) are called property dualists.

the argument from analogy to the existence of other minds.

The problem with this argument is that it seems incredibly weak. As the great Austrian philosopher Ludwig Wittgenstein (1889–1951) dismissively asked: ‘And how can I generalize the one case so irresponsibly?’ The mere fact that in one case—my own—perhaps as luck has it, there is a mental life of a particular, definite kind, associated with a brain and a body, seems to be very flimsy ground for supposing that there is just the same association in all the other cases. If I have a box and it has a beetle in it, that gives me only very poor grounds for supposing that everyone else with a box has a beetle in it as well.

on Cartesian dualism, the possibilities we all naturally believe in, namely that other people are not Zombies, and not Mutants, are themselves unverifiable! They amount to blind articles of faith.

The argument is that if mind and matter are thought of in the Cartesian way, then there would be wide-open possibilities of a bizarre kind, about which we could know nothing. So, since this is intolerable, we should rethink the conception of how things are (this is called the metaphysics).

Are we to conclude that in us, non-Zombies, mental events exist but do not do anything? Is consciousness like the whistle on the engine: no part of the machinery that makes things happen? (This is the doctrine known as epiphenomenalism.) But if minds do not do anything, why did they evolve? Why did nature go in for them? And if mental states really don’t do anything, how do they enter memory, for example?

It is due to what Locke elsewhere calls the ‘arbitrary will and good pleasure’ of God, ‘the wise architect’ who ‘annexes’ particular modifications of consciousness to particular physical events. In Descartes’s terms, Locke thinks we have no ‘clear and distinct’ idea of just what kinds of system God might choose as suitable places for him to superadd consciousness. It would just be a brute fact that the universe is organized so that some kinds of system do, and others do not, possess consciousness at all. And it is just a brute fact that their consciousnesses change and acquire definite properties at the time that their physical selves change and acquire particular properties. The contrast is between a rational and intelligible connection, such as we find in the a priori discipline of mathematics, and the fact that certain ‘motions’ just do produce the sensations in us that they do. This is the brute fact, the consequence of God’s good pleasure. Actually Locke is not so far here from the doctrine known as occasionalism, which was embraced by another contemporary, Nicolas Malebranche (1638–1715).

they provide the occasions upon which God himself inserts mental events of appropriate kinds into our biographies.

Leibniz seems to be insisting there must be a rational connection. The events in the soul must bear some quasi-mathematical relationship to the ‘motions’ in the brain and body that bring them about.

There is no independent variation whereby the physical could stay the same, but the mental be different. This is Leibniz’s position, at least as it appears in this passage. (A different interpretation of Leibniz has him thinking that there is independent variation but God has, of course, chosen the best way of associating mental and physical events.)

It is as if the world has two different biographies, one of its physical happenings and one of its mental happenings, and God had to decide how to relate them. On this account, there could be independent variation. God could have kept the physics just the same, but decided not to annex pain to pinpricks.

It is this confidence in what ought to be possible to reason that makes Leibniz, like Descartes, a ‘

they think, it has to be false that you wince because you are in pain. This bit of common sense has to be given up. You wince because of the

physical pathways, not because of a mental add-on.

Philosophers also talk of a reduction of statements of one kind to those of another. Analyses provide the reductions.

This is the analysis of what it means, or what makes it true, that a person is in pain.

You and your twin, since you share dispositions (you verifiably tend to behave the same way), share your sensations, because this is what sensations are. This doctrine is called logical behaviourism.

Behaviour is not a transparent guide to sensations, thoughts, or feelings.

They prefer a slightly more elaborate doctrine known as functionalism. This too pays prime attention to the function of the mental state. But it identifies that function in a slightly more relaxed way. It allows for a network of physical relationships: not only dispositions to behaviour, but typical causes, and even effects on other mental states—providing those in turn become suitably expressed in physical dispositions. But the idea is essentially similar.

Contemporary thinkers like to put this by saying that there are qualia or raw feels or sensations associated with tasting coffee. And friends of qualia are often fairly glum about the prospects of reducing qualia to dispositions in behaviour. As far as that goes, they are back with Locke.

This is usually put by saying that perhaps there is a metaphysical identity between mental and physical facts or events, but that it is not necessarily one that can be known a priori.

Once again, there would be a complete reduction of the mental to the physical. This would be what is called a psycho-physical identity theory.

From the subject’s perspective, anything that feels like pain is pain. It doesn’t matter if it is C-fibres, or something quite different.

Our knowledge of our pain is not hostage to the question of whether we have C-fibres inside us, or any other particular kind of biological engineering.