Presuppostion & Transcendental Inference

Humphrey Palmer

• Publisher: Routledge
• Year: 2019
• ISBN:
  9781000737103
• Edition: 1
• Topic: Filosofia
• Subtopic: Storia e teoria della filosofia

Originally published in 1985. This book is about a single famous line of argument, pioneered by Descartes and deployed to full effect by Kant. That argument was meant to refute scepticism once and for all, and make the world safe for science. 'I think, so I exist' is valid reasoning, but circular as proof. In similar vein, Kant argues from our having a science of geometry to Space being our contribution to experience: a different conclusion, arrived at by a similar fallacy. Yet these arguments do show something: that certain sets of opinions, if professed, show an inbuilt inconsistency. It is this second-strike capacity that has kept transcendental arguments going for so long.

Attempts to re-build metaphysics by means of such transcendental reasoning have been debated. This book offers an introduction to the field, and ventures its own assessment, in non-technical language, without assuming previous training in logic or philosophy.

Chapter One

IS SCEPTICISM SENSIBLE?

There is an old and honoured line of argument, impressive in presentation but of uncertain force, for refuting sceptics with. This defence against intellectual banditry was first erected by Descartes and later squared up in proper masonry by Kant; and is now available in portable concrete units, prefabricated to customers’ requirements under the brand name of Transcendental Arguments.

We are to enquire how such defences are supposed to work, and what they actually prove; but first we must see what sort of attack they are intended to repulse. What is this scepticism, which transcendental arguers will defend us all against?

There are, of course, sceptics and sceptics: as there are various things one might be dubious about, and several possible purposes in doubting them. Descartes’ main concern was with doubts that affected Science:– Was observation generally reliable? Could mathematics be mistaken? Might memories be deceptive and everything a dream? We have to consider if such very general doubts mean anything, and what he had in mind when raising them, in order to see just what he might hope to achieve by his version of The Argument.

1. EXPERIMENTAL DISBELIEF

Why not begin your thinking life again, by doubting everything? Childhood and education have left you too well padded with belief. You’ll have to cut down. Intellectual fitness demands that you make a habit of believing less. A complete fast may be best to begin with: believe nothing at all for a while. Try treating everything you ever heard as false.

At once the objection is heard: you can’t doubt everything at once. To doubt this, you must be sure of that. Some truths must be known, and admitted as such, or we shall have no standards by which other items could be reckoned dubious. A general scepticism will defeat itself. And as Descartes proposed to start with an entirely general doubt, we need not follow him beyond this point.

This objection does not touch Descartes, for the doubts he proposed raising were neither permanent nor entirely general. He just wanted to try it on, for once; to see what could be doubted if he gave his mind to it. Some opinions, surely, would be found undoubtable. Which these are, he hopes to discover by trying to doubt everything in turn, deliberately, experimentally.

But surely there won’t be much left if we insist on doubting everything we can? Our indubitables form a meagre collection, insufficient for ordinary life or even for a sceptical philosopher, so the attempt to discard all discardables will defeat itself. Maybe so; but Descartes did not propose to discard whatever turned out disbelievable. Instead he meant to select for special treatment those items which turned out undisbelievable. After turning out all the apples in the basket, lest the bad infect the good, he picks them over and puts the good ones back again (Replies 7). He is busy shaking things, to see which ones are shakeable, “that those things which cannot be shaken may remain”.

2. BELIEVING DIFFERENT

Sometimes in matters of behaviour one has to follow questionable views as though they were beyond doubt. But in theoretical questions it is just the other way about: here everything which can be thought at all dubious must be rejected as if it were completely wrong, so as to see if any beliefs are left which are indubitable (Discourse 4).

Gassendi favoured the programme of “stripping off every prejudged opinion”. But why not just say so, i.e. indicate which beliefs seem unreliable, then pick out those which stand as true? “For treating them all as false is not discarding preconceived ideas but trading them for another lot” (Objections 5).

This objection takes ‘treat as false’ to mean ‘consider to be untrue’: and surely treating–X–as–false will mean taking not–X to be true? This sceptic would end with as many opinions as before, and just as unreliable. But ‘treat as false’ may also mean ‘treat as you would treat a falsehood’, i.e. put aside or disregard. “In the search for metaphysically certain truths no more attention should be paid to doubtful items than to those obviously false – and no–one in his right mind could have read it otherwise!”(Replies 7).

The saint who loses his faith need not become an atheist. The rejection of all previous beliefs requires unbelief, not disbelief in the sense of believing something different. The ex–believer need not take on a fresh set of contrary beliefs.

3. INTENTIONAL BELIEF

Any opinion not found completely compelling should, for this once, be deliberately put aside. That is the proposal. But can you decide to believe or disbelieve? If not, then doubting–on–purpose may be a similar absurdity.

One cannot decide to believe in abominable snowmen or in the doctrines of the Creed. Our belief – what we actually think – is constrained by the facts as we find them, and having so found them we cannot decide to find them otherwise. Our vision of the facts may of course be distorted by our prejudice or preference, obscured by ignorance, or made hazy or patchy by carelessness; but none of these factors is deliberate. If Smith consciously tried to think that snowmen do exist, his efforts would ensure that that was not what he really thought (cp Evans, 145f). And if he can’t decide what to think, neither can he choose what not to think. Disbelief also cannot be deliberate. So the proposal to go round deliberately disbelieving everything is meaningless.

It is however up to us what we shall say, or do, about what we find we must believe. As theologians put it, we may ‘withhold assent’ from something that we think is true; either because we are not sure yet, or don’t trust our own judgment, or because acting on it looks like being inconvenient. And this applies outside theology as well. No–one can deliberately believe or disbelieve that three lines in a plane must form a triangle, but one can suspend belief while considering if our grounds for it are good enough: that is, one may decide not to act on it for the present, not to rely on other things which flow from it, etc. One can deliberately question a belief.

Why not then say one is questioning beliefs, putting them aside for audit at a stocktaking. Why all this parade of denial, these invented reasons for pretended non–belief? (Objections 5). Because the old familiar opinions will come running back, one relies on them still without even realizing. Freeing oneself of all the errors imbibed since babyhood is not an easy job. Some strong medicine will be needed: just saying that you could be wrong is not enough (Replies 5).

The form of the experiment is clear: trial non–belief in each item of previous belief. Failure marks an item as undisbelievable. The discovery of these items marks the success of the experiment.

The purpose of the experiment was also clear to Descartes:

I was engaged meanwhile in uprooting from my mind all the mistakes which found their way up till then -- not in imitation of the sceptics who just doubt for doubting’s sake, and make out they cannot make up their minds. No, my aim was just the opposite: to achieve conviction. To reject unstable ground and sand, so as to find rock and clay. And this I think I did achieve (Discourse 3).

4. UNREAL DOUBT

C.S.Peirce compared Descartes’ doubts to paper currency, which he clearly considered a fiddle and a sham. Enquiry, he held, must always begin from where we are, from our actual set of opinions, our existing beliefs. When one of these comes into conflict with our present reading of experience we are thrown into an uncomfortable hesitancy, a state of real Doubt, resolved only by some revision which reconciles the new experience with what still seems certain of the old; and this revised version then constitutes our new Belief. Doubt, on this view, is something that happens to us, when real opinions genuinely conflict. It is not an experimental suspension of belief.

This initial doubt will be a mere self–deception … a person may … find reason to doubt what he began by believing: but in that case he doubts because he has a positive reason for it, and not on account of the Cartesian maxim. Let us not pretend to doubt in philosophy what we do not doubt in our hearts (Peirce V #265).

Real belief is a habit of mind, a settled tendency to a certain practical response, and cannot be shaken by pretended counter–evidence. That is why professed sceptics still walk up steps and sit on chairs, without precaution or uncertainty. Real doubt would make them hesitate, at least. “So you call it doubting to write down on a piece of paper that you doubt?” (Peirce V #416).

Descartes went on writing long after denying that there was paper, pen or ink. He does not really think they have vanished, he is only playing ‘just suppose’. Peirce derides such theoretical, artificial doubts as meaningless. Yet for some purposes they are unavoidable.

In the procedure called ‘indirect proof’ the item up for proof is first denied, and that denial is then shown to be unsustainable. For example:

There is no greatest number. For suppose there were, and call it N. Add 1. The resulting sum, N+1, must be greater than N, the number we just supposed as greater than them all. But that’s ridiculous! Q E D.

Here the Q E D is stated first: ‘there is no greatest number’. It is then shown that denying this (by supposing N) would involve asserting N’s contrary as well; but that is a contradiction, so it must be wrong. Any item ‘reduced to absurdity’ like this will just have to be denied, so its contrary (the Q E D) simply must be true, being undeniable–without–absurdity.

Now this indirect proof proceeds by denying something experimentally (the Q E D). The denial does indeed turn out to be contradictory, and so not–properly–assertable; but we shall never find that out if we are not allowed to try. Once concede Peirce’s prohibition of artificial doubt, and the whole procedure of reductio becomes impossible.

Some such experimental questioning –let’s see what happens if we try denying so–and–so – is involved whenever a conclusion is established by an inference:

Socrates is wondering if he is mortal. Direct verification seems a little premature. But if he accepts that ‘all men are mortal’ then surely this general truth will also apply to Socrates?

Logic–books commonly present such reasonings like an addition–sum: premisses first, put two and two together, then see where you are. In practice, we usually think of the conclusion first but with a question–mark:

Socrates, mortal YES/NO ?

and then look around for facts and principles to prove it or confute it with. If ‘Socrates is a man’ and ‘all men are mortal’ are given, then ‘Socrates is mortal’ will (we are forced to concede) be undeniable. So the conclusion is established by trying to deny it (while affirming the premisses) and finding that we cannot do so with consistency (cp Ree 71).

If such formal and experimental doubt is involved in all deductive inference, then Peirce cannot be right in declaring that doubt is always immediate, practical and personal. And even he makes room for hypothesis:

Doubt is not usually hesitancy about what is to be done then and there … every answer to a question that has any meaning is a decision as to how we would act under imagined circumstances (V #375).

Thus if I check in to a picturesque hotel with wooden stairs and narrow winding passages, and then wonder how I might get down in case of fire, my hypothetic dither between Door and Window, if resolved, could well shape my action in a real emergency. Experimental doubt can have immediate and practical effect.

Even playful wondering–if is allowed for:

I have, for example to wait in a railwaystation, and to pass the time I read the advertisements on the walls. I compare the advantages of different trains and different routes which I never expect to take, merely fancying myself to be in a state of hesitancy, because I am bored with having nothing to trouble me. Feigned hesitancy … plays a great part in the production of scientific enquiry … when all is over … we find ourselves decided as to how we should act under such circumstances as those which occasioned our hesitation. In other words, we have attained belief (Peirce V #394, cp Palmer 1981a).

Any doubt is all right, then, so long as it ends up one day in practical belief. And this end may be reached by way of trying to doubt something basic and indubitable:

The original beliefs only remain indubitable in their application to affairs that resemble those of a primitive mode of life … (but) as soon as we find a belief shows symptoms of becoming instinctive, although it may seem dubitable, we must suspect that experiment would show that it is not really so; for in our artificial life, especially in that of a student, no mistake is more likely than that of taking a paper–doubt for the genuine metal (V #445).

You may think it open to question whether, say, incest is always and absolutely wrong. Alright, try seriously doubting it; and your own reaction may show that belief ‘original’ and indubitable.

Peirce’s trenchant original critique of Cartesian doubt has now disappeared. Like Descartes, he is now practising formal, experimental doubt to discover which doubts are basic and undoubtable. But he favours different tests for being–impossible–to–doubt. For Descartes, this privileged position is assigned only if some sort of contradiction would result from a contrary belief. Pierce takes gut–reaction as sufficient sign that a belief is really ‘part of us’.

Descartes’ doubts are formal, i.e. without special occasion in his life. Their resolution also is non–personal. They serve to select those beliefs that are logically impossible-to-doubt. This is a purely theoretical thought-experiment. But is there any point in it? Will the result mean anything, make any difference to anyone? That is what Peirce really questioned. This doubt was raised again by Wittgenstein.

5. KNOWING FIRST

Every doubt is based on some previous knowledge or belief, by which to do the questioning.

First of all, the doubter must understand his own expression of his doubt. If George says ‘I doubt whether fairies really exist’, he must first know what these six words mean, and many more, and how they are put together to make a statement or express a doubt:–

If I wanted to doubt that this is my hand, then how could I help doubting whet...

Table of contents

• Cover
• Half Title
• Title Page
• Copyright Page
• Original Title Page
• Original Copyright Page
• Contents
• Dedication
• Acknowledgements
• Analysis of chapters
• References
• Introduction
• Chapter I Is scepticism sensible?
• Chapter II The Cogito
• Chapter III What the Cogito refutes
• Chapter IV Presupposition and backward argument
• Chapter V Kant’s vindication of geometry
• Chapter VI Our world
• Chapter VII How presupposition works
• Chapter VIII Backward moves in current debate
• Chapter IX Metaphysical research
• Chapter X Arguing transcendentally
• Chapter XI Changing spectacles
• Bibliography
• Index