Alex asked:

What is Descartes Methodological Doubt, and why does he insist/want to use it? What is the one “true” idea that is derived from this doubting? What is his proof for God (the trademark version ie the causal argument), and more importantly (ie specifically),what is the problem with it – why does his argument fail – please specify in detail this problem?

Answer by Craig Skinner

Descartes was tired of scholastic philosophy, viewing it as hairsplitting logic, nitpicking metaphysics,  postulated occult powers, preoccupation with theological matters such as transsubstantiation and the holy trinity, and acceptance of Aristotle’s creaky cosmology and physics. On the other hand, he was enthusiastic about the new “mechanical philosophy” (physics), and thought such empirically-based science, coupled with mathematics, might yield more understanding and also control of nature to our benefit.

So he wanted to start from scratch and “build anew from the foundations… to establish… firm and permanent structure in the sciences”.

He says that many of his former beliefs were false or doubtful. So a new foundation had to be a belief that can be relied on as absolutely certain. How to arrive at such a belief? The first Meditation spells this out – his famous method of doubt.

He says he will doubt everything that can conceivably be doubted. This includes all beliefs based on the senses and all beliefs based on reason.

As regards the senses, we can doubt them because

(a) they sometimes deceive us, a commonplace observation.

(b) when I dream I think I am awake and doing things. So, at any time when I think I am awake, I might really be dreaming, and all the assumed external world an illusion.

(c) a malicious demon could put ideas in my mind suggesting an external world when no such thing exists.

As regards reason, he feels that although we think we know, say, 2+3=5 with certainty, again a malicious demon could trick us so that every time we add these numbers we make a mistake, thinking the sum is 5 when it isnt.

He concludes that the heavens, earth, colours, figures, sounds, all external things including his own body may be illusory.

What then is left as his foundational belief, his “one true idea” as you put it?

He tells us this in the second Meditation. He says that if he is doing all this doubting, he must be thinking, and so must exist. “I think therefore I am” (“cogito ergo sum”), as it is famously worded elsewhere in his writings.

Of course by itself this doesnt get him far. The world might consist of just one thinking thing, himself. To guarantee the rest of the world he needs the existence of the guarantor, God, a non-deceiving God at that, to be another certainty. He cant have this of course. First, to say that his clear and distinct idea of God can be relied on because the idea was implanted by God, is to beg the question. Secondly, no proof of God’s existence is sound.

But he has a go. He seems to think that God’s existence is readily evident to any diligent meditator, and that arguments are just heuristic devices to help the slower meditator to the almost self-evident truth that God’s existence is known by clear and distinct perception. So he doesnt set out his arguments formally with premises and conclusion. Also he uses a lot of scholastic terms. We meditators have to work hard to penetrate his arguments.

You ask about the causal argument (Meditation 3)

A fair reconstruction is as follows:

P1. I have the idea of a most perfect (omnipotent, eternal, infinite, benevolent) being (God).

P2. A cause must be at least as great (real) as its effect.

Conclusion: the idea of God cant come from (imperfect) me. Its cause must be God (or, impossibly, greater). God exists.

The argument is valid. To declare it unsound we therefore need to attack the premises. Both are vulnerable to attack.

Objections to P1:

(a) a finite mind cant have an idea of infinity (Gassendi’s view in 5th Objections). Descartes replied that we can. It’s our understanding that’s limited, not the the thing of which we have (limited) understanding. I agree.

(b) the meditator can claim not to have this idea. Descartes assumes we all have the same (God-given) innate ideas. We simply dont need to accept this. I dont.

Objections to P2:

P2 isnt easy to grasp. The discussion is in technical, scholastic terms. Two types of reality (being) are distinguished regarding ideas. The existence of an idea (its formal reality) is distinguished from its content (its objective reality). “Objective” refers to the object contained in the idea, rather like the modern use of “subjective” – it refers to the tree (say) in the mind not the tree in the garden. The notion of degrees of reality is then introduced. Ideas all have the the same degree of formal reality, all being mind states, but they differ in degrees of objective reality – lowest in a mode (modification of a substance eg  colour), intermediate in a finite substance, highest in an infinite substance. P2 therefore expresses the Causal Principle that the degree of formal reality of the cause must be at least as great as the objective reality of the effect, leading to the conclusion that an idea whose content (objective reality) is infinite (such as Descartes’ idea of God) cant have its cause in a finite being (with less than infinite formal reality), such as me, only in God, so that God exists.

First objection: the idea of God can come from me – having some degree of perfection, I can posit higher and higher degrees indefinitely (Mersenne’s view in 2nd Objections). I agree.

Second objection: animals and plants (greater) derive from inanimate causes (lesser), Mersenne’s view in 2nd Objections. I agree.

Third objection: P2 is just an assertion. No evidence is given for it. I  would generalize Mersenne’s objection to say that simple things plus simple rules can lead to complex things eg laws of nature plus simple initial conditions in our universe has yielded, atoms, compounds, galaxies, life and minds, so that the Causal Principle is false. To assume that a finite mind needs an infinite mind to cause it begs the question as to God’s existence.

In short, the first premise can simply be denied, the second premise is false and question begging.

In the end, Descartes doesnt get further than the cogito, so that, far from establishing a new foundation, his philosophical legacies are the idea of scepticism, and, arising from his idea that I am essentially a thinking thing, the notion of mind -body dualism. Scepticism is a commonplace now in philosophy, science and everyday thinking – we all accept that certainty is only to be found in logic and mathematics. Dualism displaced Aristotle’s substance/form view, but has proved sterile, and the superiority of Aristotle’s view is increasingly recognized.


Inger asked:

The perdurantist solution to Lump and Goliath is OK. But suppose the lump and the statue are brought into existence at the same moment, and later also destroyed at the same time. What would the perdurantist say to this? And would it reinstate the appeal of the Two Object View of Wiggins?

Answer by Geoffrey Klempner

For the past half-hour I have been trying to think of a way to explain the problem to someone who has not studied analytic philosophy. I’m afraid that many of the people reading this will think that it is just silly, that philosophy students have just been brainwashed into thinking otherwise. (No comment.)

What is the problem? We live in a world which contains lots of ‘objects’. By that I mean things you can name, or recognize, or describe, or (sometimes) pick up, or own, or etc. If you had to describe your current situation, wherever you are, you could talk about the things you can see around you, where they are placed, and so on. I’m sitting at a thing called a ‘desk’, typing on a thing called a ‘keyboard’, looking at a thing called a ‘monitor’, and so on and so forth.

What I’ve just done is state the obvious. But it’s surprising how (seeming) philosophical problems can arise out of stating the obvious.

‘Goliath’ in your example is the name of a statue (of Goliath, although it could be a statue of Donald Trump, you can call the statue whatever you like). And although no sane person would normally do this, ‘Lump’ is the name of the stuff that Goliath is made of. Let’s say bronze.

(Maybe I am the owner of Lump and I lent it to a sculptor for a specified time to make a statue out of. The statue is subsequently sold. What happens when I ask for Lump back would make an interesting legal case.)

The logical problem starts when you realize that although you seem to be pointing to the ‘same thing’ when you point to Goliath, or to Lump, this leads to a contradiction. Because there were times when Lump existed and Goliath didn’t exist, and after Goliath is melted down and made into a different statute there will be times when Lump still exists and Goliath no longer exists. A thing can’t both exist and not exist at the same time!

So Lump and Goliath can’t simply be the ‘same object’. How do you describe the situation in a way that doesn’t lead to a contradiction? Surprise, surprise, there’s more than one way.

The view of David Wiggins (distinguished British philosopher) is that there are ‘really’ two objects, even though for some of the time they occupy the same space. (Oooh! I can hear you gasp.) The history of the object called ‘Lump’ is different from the history of the object called ‘Goliath’ even though for some of that time, the two histories run side by side. Goliath stands in your front hall way and so does Lump, in exactly the same place. No two objects could be closer!

Rubbish, says the perdurantist. What the example shows is that we have to consider existence as something that pertains to a ‘temporal part’ of an object. Lump is made up of temporal parts (Lump at 2.15pm on 16th February, Lump at 2.16pm on the 16th February and so on — you can cut this as finely as you like) and so is Goliath. While the temporal parts coincide they are simply parts of Lump-Goliath. You don’t have to distinguish between the Lump aspect and the Goliath aspect of a given temporal part. However, before Lump was made into Goliath, there were Lump temporal parts which were not Goliath parts. And similarly for after Lump is made into another statue.

So what? Why can’t we simply say what we like so long as we don’t get into a logical contradiction and so long as no factual information is lost? Some ways of talking are more cumbersome than others. Going back to your original situation when you are describing the things around you, it is natural to use the language of ‘objects that persist through time’ (Wiggins), and very unnatural (to say the least) to use the perdurantist language of ‘temporally extended object parts’. Then again, there might be more complex situations (like the Large Hadron Collider?) where it was more convenient to let go of the idea that we are talking about persisting objects because it gets too messy.

Actually, I think more could be said here, along the lines P.F. Strawson describes in his book Individuals: An essay in descriptive metaphysics (1959). The building blocks of our ‘conceptual scheme’ as Strawson calls it are ordinary spatio-temporal objects or ‘individuals’. We couldn’t even get started describing ‘temporally extended object parts’ if we weren’t first able to identify and re-identify these ordinary objects. Well, then, maybe it is a case of ‘bootstrapping’, where you start with a particular conceptual scheme and use it as a bootstrap to construct a better one (for some purpose, presumably scientific).

Your suggestion (finally) is that if Lump and Goliath are brought into existence and destroyed at the same time then… what, exactly? Let’s say you pour molten copper and tin into a Goliath mould. Then Lump and Goliath come into existence at the same time. Before the bronze existed, Lump didn’t exist, although its constituents did (you can make a problem about that if you want). If you dissolve Lump/ Goliath in acid then ‘they’ go out of existence at the same time (more or less). Well, then. In that case, the perdurantist (the one who said we should talk of ‘temporal parts’) has nothing to explain. Nor does Wiggins.

Then again, you might think that even though in your scenario Lump and Goliath have exactly the same history, there are counterfactual (contrary to fact) statements about what might have happened to Lump or to Goliath, by virtue of which we are still required to distinguish them. — If you insist. Honestly, I really don’t think it matters in the grand scheme of things.


Hubertus asked:

Could an AI ever be a Philosopher?

Answer by Geoffrey Klempner

One might think that there is something rather strange about this question. An AI — an artificial intelligence — is by definition intelligent, and if any creature is intelligent, surely it can understand and grapple with the questions of philosophy, leaving aside the question whether it would want to.

Let’s first deal with the question of AI. There are basically two routes one can take. The first, which is at present the only subject of research, is to construct ever more complex programs — or alternatively connectionist networks — which approach ever more closely to the kind of verbal output that is indistinguishable by the Turing Test from a human being.

There are questions here about whether mimicry or simulation could ever be as good as the ‘real thing’ — to which the best answer (in my view) is that you need to give your AI ‘arms and legs’ (or the equivalent). A creature that has intelligence necessarily has desires as well as beliefs, and in order to have desires a great deal of physical structure is presupposed besides mere possession of a ‘computing organ’.

On this reading, maybe the first ‘genuine’ AI will have wheels instead of legs, maybe it will look more like Dr Who’s Daleks than a human being. But it will want things. It will have an agenda. When we talk to it, it will talk back because it wants to (because it is interested in us and what we have to say, even if only as a pleasant game to pass the time).

What could we talk about? Well, that’s the problem. This creature (I won’t call it a machine) has ‘desires’ that are largely incomprehensible to us. Perhaps we share intellectual curiosity, perhaps that’s enough for scientific collaboration or something similar. But that’s as far as it goes.

How about joining a Philosophy Department? Our AI would be a whizz at formal logic. However, my view, for what it is worth, is that to be motivated to philosophize one needs specifically human failings. (There’s some truth in the old joke: ‘My daughter is a Doctor of Philosophy.’ ‘What sort of illness is philosophy?!’)

Maybe, our AI would turn out to have some or all of these ‘failings’ too, maybe not. There’s no way to be sure, because we are so far from getting to the bottom of the source of the philosophical impulse that it is really impossible to say. To philosophize, you need to find, in Neo’s words, ‘something wrong with the world’. There is something wrong with the world because there is something wrong with us. That’s what the struggle to philosophize is ultimately about.

I said before that there were two possible routes to AI. The second hasn’t been tried yet, but I can’t see any logical objection to it. You start by replacing a single brain cell by a silicon substitute with identical input-output functions. I don’t want to minimize the monumental difficulty of this task, which is far beyond what present science can achieve. However, if this could be done, in principle, then by repeating the process you could create a substitute brain (and body too, with a human-like nervous system).

Why go to all the trouble? Biology is the best method we know of growing a human being but maybe in future human-like AIs could just be manufactured on a production line. Various materials go in at one end, and human replicants come out the other, just like automobiles. What would these human replicants lack? A human life. A childhood.

In principle, these could be built in too, by duplicating not just the function of the brain cells but their actual state at a given time. Then a replicant would walk away thinking that it was you, or me. In that case, your question is answered.

But I guess that’s not the answer you expected.


Ana asked:

Explain the consequences of adopting cultural relativism?

Answer by Paul Fagan

Generally, it is fair to say that persons do not ‘adopt’ cultural relativism: instead they have it thrust upon them. To explain, the culture that a person inhabits, sets norms and standards, that inculcate a person. This may become a ‘mindset’ that a person is either unwilling or unable to reject. This affects many obvious aspects of life such as the clothes persons feel comfortable wearing or the food they prefer: however, it should be appreciated that the process sinks deep into a person’s psyche reaching areas that one may not be aware are affected.

From a philosopher’s viewpoint, this may have a major consequence which will now be explained. Firstly, for those philosophers that find cultural relativism to be a hindrance affecting good judgement, it causes problems when assessing whether persons from other cultures have behaved rightly or wrongly. Generally, one’s own inculcated variant of cultural relativism would be expected to encourage criticism of other cultures; with more criticism generated the further a culture is distanced from your own. For example, cows are sacred to Hindus but (most) westerners enjoy eating beef: hence, the Hindu would be expected to find western culinary practices reprehensible. Ideally, the good philosopher should be able to dispense with their own cultural relativism when judging others. This process, and its pros and cons, is described in more detail by James Rachels in his book The Elements of Moral Philosophy; where one chapter is entitled ‘The challenge of Cultural Relativism’ (1993 (New York: McGraw-Hill), pp. 15-29).

That said, rather than ‘adopting’ cultural relativism, its quotient existing in society could be increased if it was considered to be beneficial for that society. For instance, Aristotle wished for persons to behave virtuously, where virtue may be defined as ‘a trait of character, manifested in habitual action, that is good for a person to have’ (Rachels 1993: 163); furthermore, it may be argued that greater society should benefit from encouraging such individualistic traits as their combined action would contribute to maintaining cohesive communities (Rachels 1993: 169-170). To achieve this Aristotle recommended a common education shared by all, which would be  ‘the business of the state’  and encourage solidarity amongst citizens (Aristotle 1999. Politics: pp. 180-1

For many there would be a trade-off: one may reinforce one’s community’s values but have less understanding of the values of other societies. With this knowledge some may be tempted to deliberately promote the interests of their own societies at the expense of others. Possibly, it may be argued that this has already happened in the western world before the Second World War, where unscrupulous governments achieved a greater measure of cultural relevance in their societies by appropriating the education systems and media; in turn this was used to vilify other peoples. For the moment, Western societies have opted to foster more understanding of other societies.

In concluding, the consequences of encouraging cultural relativism can be summarised quite succinctly here: the reinforcement of cultural relativism may forge cohesive cultures, which may initially seem to be benign, but this may be accompanied by discouraging the understanding of other cultures.


Joe asked:

Hi, I was wondering what Descartes view of the body is after death? Does he believe in resurrection of the body as in the Christian doctrine?

Answer by Geoffrey Klempner

What did Descartes believe? who knows? Threatened with torture by the Inquisition, Galileo was forced to recant the Copernican doctrine ‘the Earth moves’. It was a lesson not lost on Descartes, writing just a few years later. In the seventeenth century, it was no easy thing to be a man of science — a seeker after truth — and a ‘true believer’.

We can get a clue to Descartes’ religious beliefs from his enthusiastic young follower Spinoza, who wrote his first book on the Principles of Cartesian Philosophy (1663). In the spirit of Cartesian rationalism, Spinoza actively challenged the accepted Jewish view of God that had come down from the Torah and through centuries of Rabbinic commentary, arguing instead for a religion based on reason alone. He was rewarded with solemn excommunication from the Jewish community of Amsterdam.

The subtitle to Descartes’ Meditations on First Philosophy is ‘In which the existence of God and the real distinction between the soul and the body of man are demonstrated.’ That would have been enough to placate Inquisitors who didn’t think too hard about what it meant to possess a Cartesian soul. Perhaps they did not realize that the older, Aristotelian view of the soul as the ‘form’ of a living body is far more conducive to the Christian doctrine of Resurrection (a point noted by David Wiggins in his book Sameness and Substance 1980).

For Aristotle, the notion of a soul (in Greek psuche or ‘breath’) existing apart from a living body is unintelligible. For Descartes, on the other hand, although needing a body in order to perform physical actions, the soul is a non-physical substance in its own right. The more philosophical Inquisitors might well have reasoned (perhaps some did) that this could be considered the basis for a charge of heresy. As the idea wasn’t taken further, the point is moot.

Why insist on resurrection? Because without a body, the notion of ‘reward’ or ‘punishment’ is all but meaningless. If there is no reward or punishment, in any real sense, then the idea that God has ordered the world ‘for the best’ is no longer believable. The guilty who escape punishment in this world must be made to pay for their sins. The innocents who suffer will be compensated by a blissful afterlife. Meanwhile, the majority who have sinned but not sufficiently for eternal damnation, can look forward to a few hundred or thousand years in Purgatory examining in detail each and every time they strayed from the path of Christian virtue before they are finally released.

As an atheist, I value the philosophy of Descartes for the questions it raises our conception of the mind and its relation to the physical world. This isn’t about belief but about logical argument. It remains the case that the Cartesian view of the soul is compatible with resurrection of the body, so if you are a Catholic then you do not have to feel that your beliefs have been challenged at the root. That was perhaps enough to save Descartes from the grasp of the Inquisitors.


Lecho asked:

Are Psychology and Materialism compatible?

Answer by Danny Krämer

This question boils down to the question of the relationship between psychology and the other natural sciences. Descartes famously argued, that body and mind must be two very different substances. But since the scientific revolution, it is difficult to defend some form of dualism. How should the two substances interact — and they for sure do, because I can consciously move my body by thinking about it — without contradicting the natural laws like the law of energy conservation? But it is also a difficult question how a materialist worldview can explain the mind. I will talk now about some materialist proposals. I start with the theories that I find rather unplausible and end with the one I think is the most promising.

First, there is eliminative materialism. This form of materialism argues, that the predicates of our folk psychology, like belief, wish or desire are empty. When we talk about the behaviour of other people, we explain their behaviour by reference to their beliefs and desires. The eliminative materialist says, there is nothing like a belief or a desire that can be identified by neurobiology. These concepts are like the concept of phlogiston. They are concepts of a bad theory and when we have a better theory we can drop these concepts altogether. So materialism is not compatible with folk psychology but with a psychology to come, the eliminativist argues. I think that is just a very bald speculation about the future of science. Today there is no reason to believe, that our best psychological explanations will not contain the concepts of our folk psychology. Most of psychology is belief-desire-psychology and neurobiology is not even close to explain the complex behaviour of human beings without the concepts of beliefs and desires.

The reductive materialist is something more liberal. He thinks there will be a theory reduction. Psychological predicates will be reduced to predicates of neurobiology and in the last instance to physics. What does this mean? Let’s take the predicate “pain”. The reductive materialist thinks that the predicate “pain” will be identified for example with the predicate “c-fibres firing”. Every time someone is in pain her c-fibres fire. Do this reduction with all psychological predicates and you have a reduction of psychology to neurobiology. Psychology and Materialism are compatible because the predicates of psychology are coreferential with some predicates of physics. But there are some problems with this proposal too. For example, pain may be realised in humans by firing of the c-fibres. But what about an octopus or a martian? They do not even have c-fibres but they may still be in pain — the octopus shows clearly pain behaviour if you hurt him. That is the so called argument from multiple realisations.

How to solve the problem? The most promising form of materialism is, I think, nonreductive materialism. That means you believe that everything supervenes over the material, i.e. if you destroy all matter there will be nothing left. But you do not think there must be some theory reduction to make this claim true and you can bring good reasons why some predicates cannot be reduced to physical predicates. I think the reason for that is, that most of the predicates we use are multiply realisable. Take the predicate “money”. Money can be made of paper, metal and even bits on a computer. Most of the money nowadays is virtual money. But if you destroy all computers and all the cash, there will be no money any more. Or take “pain”. Pain is realized in humans, let’s pretend, by firing c-fibres, in martians maybe by some organ made of silicon. These are predicates that are more abstract than for example a predicate of physical science. “Electron” only refers to electrons. But “money” can refer to paper, pieces of metal or bits in a computer. What counts here is not the material but the role the thing plays in a wider context, or like Aristotle would say its form. But still: destroy all matter and there will be no money and no pain whatsoever.

So all these forms of materialism argue that Psychology and Materialism are compatible, and I think, some form of nonreductive materialism is true.


Philosophizer by Geoffrey Klempner

'Philosophizer' by Geoffrey Klempner


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