by Julia Annas
This is, of course, an ideal, something emphasized by the way that the only people who, Plato thinks, have a chance of attaining it are those who are exceptionally talented by nature and have been brought up in ideal cultural circumstances. This warns us against thinking that we can find any actual example of knowledge. The expertise model on its own seemed to hold out the chance at least that knowledge was attainable. But when the requirements are made as formal and demanding as they become when mathematics is the model, the conditions for knowledge get set so high as to be unattainable by us.
Understanding and the sciences
Aristotle, in this as in many matters Plato’s greatest pupil, takes over the Republic model, but with important modifications which make it philosophically far more fruitful. He develops the idea in his work on the structure of a completed body of knowledge, the unfortunately titled Posterior Analytics. (It is so called because it follows his treatise on logic, the Prior Analytics.)
For Aristotle, Plato goes wrong in thinking that all knowledge hangs together in a unified structure. This makes the mistake of thinking that all the objects of knowledge together make up a single system, and can be known as such. But, Aristotle thinks, there is no such single system; different branches of knowledge employ fundamentally different methods, and do so because their subject-matters are fundamentally different. Aristotle does not disagree that something like Euclid’s geometry is a reasonable model for knowledge; like Plato, he is willing to appeal to mathematics to beef up the idea of expertise. But there is no such thing as knowledge as a whole, only the different kinds or branches of knowledge – or, as we are tempted to say, sciences. (The Greek word for knowledge, episteme, forms a plural, but we cannot say ‘knowledges’, and have to make do either with ‘branches of knowledge’ or ‘sciences’. This can obscure the way that, for example, Aristotle’s notion of a science is a restriction of Plato’s conception of knowledge.)
As well as this radical ‘departmentalizing’ of knowledge, Aristotle imports a further difference. Whereas Plato focuses relentlessly on the individual knower, Aristotle widens his epistemological view to take in many aspects of the social production of knowledge. It is not for nothing that ‘science’ is more appropriate to Aristotle’s discussions of knowledge than to Plato’s. Aristotle is aware of the way that the development of a science, such as biology, requires research and observation from many people, and also that the single investigator does not reinvent the wheel every time, but relies on others’ results and data and, more importantly, on their questions and setting of the problems. He himself begins his enquiries in a number of fields by first canvassing views on it that are reputable and widely held, or put forward by philosophers or other investigators. It is by entering into this tradition of previous enquiry and exploring the problems that it has thrown up that the investigator can make progress.
Hence Aristotle can distinguish (though it would have been nice if he had done so more clearly) between different aspects of the development of a body of knowledge. The data and observations a science relies on, built up by the co-operative activities of many people, are material for a science, not science itself. Pieces of information do not constitute knowledge until they are fitted into and form part of a structured system. Hence before they amount to knowledge, the results of research and observation must be given a place within the appropriate structure. In the Posterior Analytics this structure is laid out very rigidly, and the influence of the mathematical model is very obvious. The first principles of a science must be true, primary and immediate, hold necessarily and be explanatory of the results that they are the first principles of. Much effort has gone into exploring ways in which a science like, say, biology could fit such a model, and it is generally agreed that the model is unsuitably rigid for many Aristotelian sciences. The overall point is not lost, however: empirical research is needed to gather any information worth knowing, but knowledge comes only when we see how it fits into a formal explanatory structure.
Both Plato and Aristotle have an extremely ideal model of understanding. Neither doubt that knowledge is possible in principle, though for Plato particularly the conditions become very idealized and removed from everyday life. Of course, given that they are working with the expertise model, the idea that knowledge is possible is not very radical. But what they are claiming is that we can have knowledge not merely of humdrum matters but of philosophically challenging and worthwhile subjects. Some version of this claim is common in most ancient philosophical schools.
Scepticism and belief
This is not the only approach to knowledge, however; we find very different ones. The most radical of these is traced in part to Socrates and in part to Pyrrho, a later philosopher who also wrote nothing. This is ancient scepticism (making Socrates one founder of scepticism). Unlike modern scepticism, the ancient movement does not limit itself to denying that knowledge is possible, leaving us with true belief. Ancient scepticism is as concerned with holding beliefs as with knowledge, and is best thought of as an intellectual position concerning the powers of reason, one far more radical than modern scepticisms.
The sceptic begins like everyone else, by searching for truth and for knowledge. This he does by investigating, querying others’ reasons for what they claim, and looking for supporting reasons for positions of his own. So far there is no disagreement with the basic idea that knowledge requires the giving of a reasoned account. Knowledge of any kind worth having (that is, not knowledge of everyday bits of information) requires that you be able to give satisfactory reasons for what you claim. What distinguishes the sceptic from other philosophers is just that he never regards himself as having got to that point. The Greek term skeptikos means, not a negative doubter, but an investigator, someone going in for skeptesthai or enquiry. As the late sceptic author Sextus Empiricus puts it, there are dogmatic philosophers, who think that they have found the truth; negative dogmatists, who feel entitled to the position that the truth cannot be found; and the sceptics, who are unlike both the other groups in that they are not committed either way. They are still investigating things.
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Pyrrho of Elis (c.360 – c.270 BC) is, like Socrates, an influential philosopher who inspired others but wrote nothing himself. His life is even more elusive than that of Socrates, and unlike him he left no visual image.
Originally a painter, Pyrrho at some point was influenced by various philosophical schools. He accompanied Alexander the Great on his conquest of northern India, where he encountered Indian ‘gymnoso-phists’ or naked wise men. It has been claimed that this encounter was decisive for his own philosophical stance, and similarities have been claimed between reports of his arguments and early northern Indian Buddhist texts. The Greeks, however, found no problem in interpreting Pyrrhonism in Greek terms, especially as Pyrrhonists always argue against the views of others, and so developed a repertory of attacks on existing philosophical theories.
Pyrrho himself impressed others by the example of tranquillity and impeturbability he gave in refusing to commit himself to any dogmatic belief. Stories about him abound, but are mostly hostile jokes to the effect that he suspended judgement in everyday matters, thereby making himself ridiculous. Other stories say that he lived a respectable life and that Elis exempted philosophers from taxation in his honour. His pupil Timon wrote satires against dogmatic philosophers, and also prose accounts of Pyrrho’s arguments which, though problematic, show them as forerunners to the later versions of these arguments, especially those found in our main sceptical text, Sextus Empiricus’ Outlines of Pyrrhonism (of uncertain date but probably second century AD).
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Why the problem? Surely if you investigate you will turn up some results that can count as knowledge or at least as belief. Sceptics think that, while we want to think this, it will always turn out to be rash (or ‘precipitate’) assent: we committed ourselves too soon. Real inquiry, thorough investigation, will reveal that the situation was more complex and
problematic; we turn out never to have reason to commit ourselves one way or the other, and so end up suspending judgement – that is, having a detached and uncommitted attitude to whatever the issue was.
At first this sounds ridiculous, indeed unserious. Does the sceptic really hold that we can never establish what time it is, that the sun is shining, that this is bread and not grass? This is an ancient reaction, but a mistaken one.
Pyrrho, the founding figure of one branch of scepticism, is someone about whom we know little, and our accounts of his intellectual attitudes are frustratingly meagre. His uncompromising attitude about our never having reason to commit ourselves to anything led to unfriendly jokes, such as that he had to be looked after by unsceptical friends to stop him walking off cliffs, and the like. But there is an alternative tradition to the effect that he lived a normal life, so it is most probable that, like later sceptics, he took it that even when we cannot commit ourselves to beliefs we can live by the way things appear to us.
Later sceptics who took their inspiration from Pyrrho developed the idea that we ‘live by appearances’. That is, all we need to live is for things to appear to us in one way rather than another. If we go beyond this (which we get inclined to do when we move on from everyday matters to issues where there is dispute and complexity) and try to commit ourselves to beliefs, we will always in fact find, if we investigate rigorously, that we cannot commit ourselves; there turns out to be equally good reason on both sides of the question, so that we find ourselves equally inclined both ways, and so end up uncommitted, suspending judgement on the issue. This does not leave us paralyzed, however, since we still have the appearances to live by. The fact that I cannot commit myself does not stop things appearing to me one way rather than another. Being rationally uncommitted does not do away with all the other sources of motivation that get us by – habit, desire, fear of the law and so on. The view that if reason does not commit us we cannot go on living comes from an over-estimation of the powers of reason, which we do not always need and which tempts the dogmatist into committing herself prematurely to the truth of some theory.
Moreover, the sceptics go on the offensive here. What we want out of rational commitment to our beliefs, they hold, is happiness, which is to be found in peace of mind; we want to feel confident about the way things are and not worried by our uncertainty about them. But commitment to positive or negative theories on the topic can never do this; all it can do is displace or redirect the original anxiety. Only the sceptic, who realizes the futility of commitment to belief, is tranquil; rigorous investigation brings suspension of belief, and this brings the peace of mind that had been sought in the wished-for answers. Hence only the sceptic gets what everyone else is looking for, peace of mind. But she gets it only by not looking for it, merely being there when it arrives; and it arrives as a result of the rigorous investigation that makes it impossible to commit yourself for or against any position.
There is much in the sceptical story that is implausible, or seems forced. Moreover, problems lurk which can be barely mentioned here. What is the scope of the sceptic’s suspension of belief? Does it extend only to matters on which she investigates? If so, does she have some beliefs, namely the unproblematic ones? Anyway, what is the sceptic doing telling us all this about how to achieve peace of mind, how others fail, and the sceptic succeeds? How can she do this without holding beliefs?
Ancient scepticism is one of the most interesting and subtle philosophical positions. Like its dogmatic cousins, it embodies strong assumptions about reason, though subversive rather than positive ones, and is both deeper and broader than modern forms of scepticism which limit themselves to complaints about knowledge, and may reject some subject-matters on the basis of uncritically accepting others. Ancient sceptics, unlike moderns, are uninterested in carving out a position within philosophy; they think that philosophical reason, when exercised, will always undermine itself.
Socrates provided an alternative inspiration for the other branch of ancient scepticism, which took over Plato’s Academy from the middle of the third century BC until its end in the first century BC. The Academics held that philosophizing in the spirit of Plato should take the form of doing what Socrates did, namely undermining the claims of others while putting forward none of your own. Hence the sceptical Academics spent their time arguing ad hominem (that is, not from any position of their own but only from premisses the opponent accepts) against dogmatic philosophers whose claims they thought inadequately grounded, mostly the Stoics. Unlike the Pyrrhonists, the Academics made no claims about happiness or peace of mind. Their assumption about reason is simply that dogmatic philosophers have always been too hasty; their claims can be overturned from within and not by relying on the establishment of other positions.
Varieties of knowledge
So far we have seen bold and radical positions, both positive and negative, about knowledge and belief. It would be misleading, however, to give the impression that ancient concerns with knowledge always focus on wisdom and understanding; we can also find concerns which overlap with modern ones. Plato, for example, produces interesting arguments against relativist theories of knowledge which do not rely on any of the special features of his own ambitious account. A relativist, such as Protagoras, against whom Plato argues in the dialogue Theaetetus, claims that for someone to have a true belief is no more than for something to appear true to him, and hence that truth is relative to the believer. This can seem at first like a liberating discovery, especially since it defuses all disagreement. The wind appears hot to me, cold to you; we are both right, and there is nothing to argue about. Protagoras, however, puts his relativist theory forward as a theory, something we should accept and take seriously (if only in order to be liberated from our disagreements). But if Protagoras is right, the truth of his own theory is relative to him – that is, it is just the way things appear to him. And why ever should we accept, or be interested in, what happens to appear a certain way to Protagoras? If we are to take relativism seriously as a theory, then relativism cannot hold of it. (Versions of this powerful point are still being made against modern forms of relativism.)
Plato is also interested in the question of what is going on when we are said to know particular facts, and this is developed by the Stoics, who retain the expertise model for what they call knowledge proper, but also develop an account of what they call apprehension, which amounts to one way of thinking of knowledge, especially in some modern epistemological theories. Apprehension is what you have when you are so related to an empirical fact that you cannot be wrong about it. The Stoics put some effort into working out what the conditions have to be for this to hold. Roughly, the thing in question has to make an impact on you, an impression; and this impression must come from the thing in the right way – the causal story must be the right one; and the impression must be one that you could not have had from any other thing, however similar. These conditions were seen as a challenge to produce counter-examples, where the conditions are all met, but we have to agree that we do not have knowledge. The Academic Sceptics in particular carried on a long debate with the Stoics on this topic, as a result of which the Stoics seem to have introduced further conditions and modifications.
Finally, we do find, in the range of ancient epistemological theories, one which seems to meet the desiderata for a modern theory, namely that of Epicurus. For Epicurus does worry about scepticism in the modern sense – that is, the person who rejects the idea that our beliefs might ever meet the criteria for knowledge – and he thinks that he has to establish the possibility of knowledge against this challenge. He thinks of knowledge not in terms of the expertise model, but in terms of the knower’s relation to particular matters of fact. What I know, then, are for Epicurus primarily particular pieces of information to which I am related in such a way that my relation to them constitutes knowledge; these are the primary items that are known. Anything more ambitious than this has to be shown to be built out from these primary items in
the most economical and careful way that is feasible.
Epicurus’ theory is, untypically for ancient theories, rigorously empiricist – that is, it begins from and relies on our sense-experience. What I know comes to me through the senses, since only sensations relate information to me in a way which is unmediated by a process which could involve error. My ordinary beliefs, arrived at in ways which involve inferences going beyond experience, contain truths, but also falsehoods that have crept in through the human propensity to get things wrong. But if I concentrate only on what the senses tell me, I cannot go wrong. For Epicurus, belief and reasoning are sources of error, not, as for most other schools, the source of our ability to correct error. Error, then, comes in only when I start adding beliefs to what the senses tell me. Hence it turns out that what the senses tell me is not even as extensive as claims about tables and towers – since obviously these can be mistaken, as when we judge from a distance that a square tower is round. Rather, the reports of the senses are limited to how the tower appears to us from a particular perspective at a particular place, and so on. Hence we have knowledge, since we cannot be wrong about this. We could, however, be wrong about the tower, since we might make a claim that did not make due allowance for perspective, distance etc. Our knowledge turns out to be far more limited than our everyday observations about the world around us.
