Our knowledge of Sextus Empiricus, like that of so many historical figures of these ancient times, is disconcertingly fragmentary. The philosopher Luciano Floridi’s detailed account of his life and works begins with the admission that ‘…we know almost nothing for certain about the life of Sextus Empiricus, our chief source of information on ancient scepticism’ (Floridi:2002:3). Similarly, the scholars Julia Annas and Jonathan Barnes, make a similar point, that ‘scepticism is one of the high points of Greek philosophy and Sextus Empiricus is one of the most important ancient philosophers and yet ‘about Sextus himself we know very little’ (1994:ix & xii). For us though, despite gaps there may be in his biographical record, his ideas – those of which we do have knowledge – are pivotal to our study of scepticism.
What we know of Sextus
Sextus is generally spoken of as having been a medical practitioner working in Alexandria in the 3rd century CE. The ‘best guess’ dates for Sextus are that he was born c140-160 and died c220-230CE with his main work having been conducted around 180-190 CE. His actual occupation is not known for certain, and neither can we be sure where he lived, whether in Greece, Rome or Alexandria (Floridi:2002:4-5). What we do know from Floridi though, is something of his educational background. We know that Diogenes Laertius believed Mendotus of Nicomedia (c2nd century CE) to have been the instructor of Herodotus of Tarsus (c2nd century CE) and that it was he who taught Sextus Empiricus, both of whom were Pyrrhonists (Floridi:2002:4-5). Clearly then, some sort of Pyrrhonist tradition existed during the years between Timon’s account of Pyrrho, our main source of information on Pyrrho, and Sextus’s writings.
It might be thought odd that we should be attaching so much importance to an historical figure about whom we know so little. Adrian Kuzminski points out that although there are gaps in our knowledge of Sextus, his writings ‘cover a wide range of Pyrrhonian topics’ and are ‘delivered with the quiet assurance, objective voice, and breadth of knowledge of a true expert’. Moreover his ‘works are a goldmine of information not otherwise found, on nearly all the major philosophical schools of classical Western antiquity’. ‘He writes’, says Kuzminski, ‘with the authority of a Pyrrhonian practitioner’ (2021:36). Likewise, the historical philosopher R. J. Hankinson argues that Sextus ‘was recognised in late antiquity as an important figure and his version of Pyrrhonism became canonical’ (1995:6).
Sextus’ core idea
What follows is very much an outline account Sextus’ work which I fear, barely does justice if at all, to the richness of his thought. Sadly there is not the space to be able to discusss adjacent topics such as Epicureanism and Stoicism, and their relationship with Pyrrhonism. These topics must await a further publication.
Many commentators have rightly pointed out, there is nothing in Sextus Empiricus’ work that is essentially new about scepticism. He discussed Pyrrho’s ideas in general in Outlines of Scepticism (Annas & Barnes: 1994) and then applied them in various circumstances in two further books – Against the Physicists I &II and Against the Ethicists (Bury: 1936). What is important is that in applying the ideas of Pyrrho, Sextus integrates Pyrrhonist scepticism into empiricism to the extent that they become effectively, one idea. This is key to our understanding the impoartance of Pyrrhonism for our own times.
We saw in the last chapter that it was said by contempories, that when empiricism began to emerge from a belief in deities and magic in the 7-6th centuries, scepticism grew out of it almost naturally, as people started to question the truth of their empirical reality. That early scepticism though, was of a dogmatic kind, simply announcing the uncertainty about what had previously been regarded as certain… either certain religious belief or secular certainty. Sextus’ scepticism, however, was of a Pyrrhonean kind. It did not end its analysis by announcing that there was no truth as the dogmatists did, but went on as Pyrrho recommended, to apply those critical analyses to its own thoughts and speech.
The result was a transformation. This seemingly tiny change made a massive difference although not, I must admit, immediately. For some time it was not a particularly popular ideas. It was more complicated than dogmatic scepticism. By avoiding the performative contradiction implied in the implied central dogmatist statement of ‘the truth is there is no truth’, Pyrrho’s extra step of including ourselves in the sceptical situation might have been thought to have destroyed altogether the possibility of knowledge. Human-made knowledge was almost as logically impossible as it had been with dogmatic scepticism. And that was pretty well where Pyrrho left it. But, whereas Dogmatic scepticism regarded human empirical faculties to be at fault in that they seemed unable to provide the certainty that had previously been experienced in religious thought or in secular certainty, Pyrrhonism was again different.
Pyrrho turned empiricism from being part of the problem of knowledge to being part of the solution to it, for he did not criticise the central human faculty of knowing the world through our sense – our empirical faculties. And without retreating back into dogmatism, Sextus Empiricus enabled the sceptic to speak. We shall see that Sextus considered that it was indeed reasonable to make knowledge about the world…
(i) where belief was not involved,
(ii) where the evidence of the senses was clear and apparent and
(iii) where human statements about the world were conducted in a tentative manner… the speaker always being aware that such statements were provisional.
This was the epistemology of Sextus, effectively merging scepticism with empiricism into a composite epistemological concept.
A first hint of possible problems in applying Pyrrhonist ideas to everyday life is apparent from the fact that it doesn’t seem to have been particularly popular in the 600 odd years between Pyrrho and Sextus, at least not until close to the turn of the millennium when Aenesidemus began to write on Pyrrhonism. Sadly, as in so many cases, his primary accounts are now lost.
Until Aenesidemus, the major sceptical thinkers were mostly ‘dogmatic’ in their approach to knowledge and after Plato and Aristotle, those that studied in the academies that followed them came to be known as academic sceptics. Henrick Lagerlund (2020) and Harald Thorsrud (2009) give good accounts of this early form of scepticism. The tradition can be seen in the writings of Arcesilaus (316-241 BCE), Carneades (214-128 BCE), Clitomachus (187- 110 BCE), Philo of Larissa (159-84 BCE), Antiochus (130-68 BCE) and Cicero (106-43 BCE) (Thorsrud:2009:8). Of Anesidemus, again little is known of him too except via Diogonese Laertius, who says that that the academic tradition of scepticism had for Anesidemus become especially dogmatic and insufficiently sceptical and that as a result, he turned from the academics towards the ideas of Pyrrho.
A second area of complication in any easy acceptance of Pyrrhonism, relates to Sextus’ own difficulty at times, in accepting an alignment of his professional practice with the medical empiricism of his day. Thus, the question arises whether Pyrrhonism really could be put into practice at all. However, the argument of this chapter is in the affirmative; Sextus Empiricus is an important historical figure. His treatment of Pyrrhonism gave us a glimpse into a way of life, a potential application of Pyrrhonism through empiricism, that is still available to us in our modern world.
The working definition of empiricism that we have been using in this exploration has been that empiricists have an awareness of aporia (in the sense of an awareness of an apparent horizon of human knowledge), followed by a response to it that suggests they know the world -tentatively – through human senses and the sense that can be made of them’. The question is then, can we see this process at work in Sextus’ writings? We know Sextus is a Pyrrhonist, but is he also an empiricist in the way we have been describing it and if so, what is the relationship between these two epistemologies? The answer is again in the affirmative.
Aporetic awareness in Sextus’ work
Sextus provided a detailed description of examples of how particular life experiences led to ways of sceptical thinking – ones that would engender in the maker of knowledge, an awareness of aporia (Outlines of Scepticism, Section xiv). He called them ‘modes’ – they are sometimes referred to as tropes. It is through these that people are brought to see that scepticism should be taken seriously. Sextus refers to fifteen of them – ten attributed to Aenesidemus, and another five, said to have originated from Agrippa, a Pyrrhonian philosopher from around the end of the 1st century CE. Sextus also offered reasons why one might find causal arguments wanting. We shall defer our consideration of these until we encounter the work of David Hume in the eighteenth century, for Hume offered what I think is a particularly neat and persuasive account of this feature of Pyrrhonism.
We have already encountered several of the modes for ourselves in earlier chapters, as we questioned the nature of historical knowledge. It was that questioning which set us off on the enquiry in the first place. Examples of these include the way that people have different perspectives on the world, through which they read evidence in different ways and also regressive arguments, whereby any definitive statement about the world requires justification, which in turn requires further justification and so on in perpetuity. (Annas & Barnes: p44-45).
Sextus clearly saw that aporia faced us at the end of every enquiry. This is because, as to justify any statement about the world, it is necessary to give another, and so on, and a final resolution could not be achieved without without moving from reason into belief. We can easily see how this works.
So, in answer to the question ‘how do we know today is Saturday?’ we may answer ‘well, we look in the diary and it tells us what day of the week it is.’ To this we may ask’ why is looking in the diary reliable?’ Again we may say ‘It is reliable because that is how people generally know which day of the week’ but this could be countered by ‘…but could everybody be wrong?’ Then we may say ‘it doesn’t matter whether everybody is wrong or not – that is what we call Saturday…what everyone says it is’. The answer might be ‘so we don’t really know that today is Saturday at all, do we? Why don’t we just make up a name for it ourselves?’ ‘ Well it is important that we all use the same word, else we could become confused’. ‘Why does it matter if we are confused?’ And so the hypothetical questions could go on and on.
Shortly after I discovered the ideas of Sextus Empiricus, Keith Jenkins and I tried doing this regressive analysis one evening while we were chatting. In our case it was about the existence of the blazing coal in the fire in front of us in The Hurdlemakers’ Arms, in West Sussex. We went on and on discussing the fire, seemingly not able to stop, arguing why and how we might know whether the fire existed or not. In the end the pub closed and we were asked to leave! And that is the point. At some stage, into whatever it is we are inquiring, we should have to, or want to, stop the enquiry. In normal everyday life we may not go very much further than one or two of these steps, before simply accepting the reason we have given ourselves, or which others have given us. In academia typically we may go a lot furtjer and in research, more yet. But always in the end, the pub closes, someone gets fed up with the discussion, the hypothetical ‘other person’ insists they are right and uses pressure of one sort or another, so that we stop emquiring. Maybe the essay, article, PhD thesis or whatever it is, must be written…we call it ‘cooked’ and we accept an explanation as being good enough. Sextus questioned what should be the Pyrrhonists response to this. His answer – his response to aporia – was that, certainly in principle, and where possible in practice, Pyrrhonists should adopt an attitude of quietude.
They should suspend their judgement about the nature of statements about the world i.e. they should not conclude that the world was like this, or like that. If they could not reasonably decide between different perspectives in an obvious way, any resolution was likely to involve a belief – a belief that ‘this’ resolution was better than ‘that’ one. Therefore Pyrrhonists should step back from moving from reason into belief.
This is absolutely central to Pyrrhonism, and it marks the core difference between Pyrrhonist and dogmatic scepticism. What we are seeing here is that when faced with a dilemma of this kind, some believe that it can be simply resolved by following ‘the evidence’. Others – sceptics – have recognised that whatever resolution to aporia they offered, that resolution itself could itself be challenged, and so on to infinity. Consequently, they believe that certain objective knowledge of the world is impossible, oblivious to the fact that they have just contradicted themselves by saying that.
Pyrrhonian sceptics, however, conclude things differently. They think that they will find tranquillity – i.e. a mental resolution – by two means. First, they should respect aporetic awareness, and not affirm anything about any externality and second, they should report only the process that has produced that suspension, not go beyond it. To be clear, Pyrrhonists should not rush to judgement – to assessment – not rush that is, to any kind of biased or belief-inspired assessment of what we ‘see’ around us. This then is the empiricism that characterised Sextus’ work and perhaps accounts for his name too. It is also, though, the tricky part of Pyrrhonism. This is why it is so much easier to be a dogmatic sceptic.
Sometimes, the Pyrrhonist position is recorded as Sextus arguing that one should simply not believe in anything. The scholar Richard Bett and his followers, have made much of this and the obvious difficulties that might follow from such an epistemology. However, I think that a more nuanced account of Sextus’ response to aporia, is possible.
Sextus says there are three basic approaches to knowledge. First the dogmatist (or secular certaintist…or indeed our own normal everyday unthinking and informal approach to knowledge) thinks that they can find knowledge, whether through empirical evidence or through argument, aided by a dash of belief. Second, the dogmatist (or academic) sceptic believes that it is impossible to find such knowledge, because our empirical faculties cannot provide the desired for certainty. Third, the sceptic (or Pyrrhonist) is unsure and has not stopped looking (Bk I, S1-3, A&B:1994:3).
We shall see later in the book that it is this …having not ‘stopped looking,’ that enables us, as modern Pyrrhonists, to move on, if we wish, from the dilema of scepticism and thus in passing, also from the negativity of postmodernism. Moreover it is this having not ‘stopped looking’ which summarises our modern empirical scientific world of today. When we sy we ‘know’ something empirically, we mean all ths. We mean that at the end, in the so called final analysis, we appear not to be able to ‘know’ with any absolute certainty but that this doesn’t stop us from being satisfied – making do – with our best attempts, depending on the circumstances.
To be clear, and at the risk of iritating repetition, Sextus advocates that we should avoid dogmatism by simply reminding ourselves, just as Pyrrho recommended and as we have discussed here, that all statements about the world, even our own – actually importantly our own – can be countered by opposing ones. Moreover, to judge between them – to provide certainty – we should need to make further statements that lead us into the cul-de-sac of a regressive analysis (Annas & Barnes: 46-49). In that sense there can be said to be an equivalence between arguments for or against any particular statement about the world. Equivalence here means that what looks liked a settled issue can always be challenged. To keep looking, until one sees this equivalence in argument, it is obviously necessary not to settle too rashly …too quickly, on any belief-inspired assessment. This kind of empirical passivity is what ‘understanding the world through our senses’ means, and what is expected of the Pyrrhonist, Sextus suggests. It is the basic empirical stance then as now. But if sceptics cannot affirm anything, how can they speak; how can they fulfil the second part of their response to aporia and make sense of their senses?
The Pyrrhonist’s voice – making sense of medicine
In fact, Sextus does agree that sceptics – empiricists – can actually speak. Providing they do not slide into belief; they can indeed make knowledge. For example, in answer to the question of whether a Pyrrhonist can belong to one of the medical schools of the times, his answer makes it clear that they can. He said,
If you say that a school involves adherence to a number of beliefs which cohere both with one another and with what is apparent, and if you say that belief is assent to something unclear, then we shall say that Sceptics do not belong to any school. But if you count as a school a persuasion which, to all appearances, coheres with some account, the account showing how it is possible to live correctly (where ‘correctly’ is taken not only with reference to virtue, but more loosely, and extends to the ability to suspend judgement) – in that case we say that Sceptics do belong to a school. For we coherently follow, to all appearances, a life in conformity with traditional customs and the law and persuasions and our own feelings. (Sextus Empiricus: Outlines of Scepticism: Bk1, Para. viii: in Annas Julia & Barnes Jonathan [eds.] 1994:7).
And there we have Sextus’ answer to this central question about Pyrrhonist knowledge. The last few lines of that abstract make clear that the Pyrrhonist can follow their cultural customs; they can abide by the law, follow matters that are entire clear and logically persuasive and also …importantly, tentatively follow their own feelings. Sextus discusses in his later books (Against the Physicists I & II and Against the Ethicists) some examples of how this position works for life in his time. As we follow Pyrrhonism through the western intellectual tradition, we shall see for ourselves how these categories work out in practice…in ‘our’ real life and in our own time.
We encountered Frede’s reading of Sextus in an earlier chapter, but it is so helpful to an understanding of the Sextan position that it bears repeating. Pyrrhonists, he says,
follow what appears to them to be the case without committing themselves to the view that what appears the case, actually is the case. (Frede:1987:252).
From this it may be concluded that Pyrrhonists are inherently duplicitous, but it doesn’t work like that in practice. By way of example, to understand his position, it is worth looking at Sextus’ reaction to the medical schools, It is a delicately balanced one.
There were three of these schools of medical theory in Sextus’ time – the Rationalistic, the Empirical and the Methodical. They were in competition which each other and marked a point in the expansion of medical thinking as it moved from rationalism to empiricism and later to a synthesis of them, via the physician Galen, who we shall briefly consider in the next chapter.
The first of these, the Rationalistic school, was sometimes called the Dogmatic School. It was said to have been founded by Polybus (c400 BCE) to put into practice the rationalistic ideas of his father-in-law Hippocrates and those of the so called Hippocratic Corpus (a collection of some 60 medical writings) around 460 – 370 BCE.
In outline it was like a medical version of the secular certaintists noted in the last chapter. The Rationalist School of medicine believed that to cure people it was necessary to know their underlying condition as they supposed it to be – that which was not, as they believed, apparent to the eye.
Moreover to be able to do this, the medical practitioner had to have an extensive knowledge of the human body, a process of learning that was difficult, lengthy and expensive to acquire. The Hippocratic tradition relied importantly on theories of the body, not least that of the supposed four humours of black bile, blood, phlegm and yellow bile and the need for there to be maintained in the body a balance between them.
The Rationalist School decried the learning of medicine by folklore or mere experience – which was the method of the time available to the poorer people. The Rational or Dogmatic School of medicine held sway until challenged by empirical medical practitioners and philosophers of Alexandria (founded around 330 BCE) who claimed to be able to rely on experience alone in curing illness. There developed a standoff between these schools. It was held that ‘Rationalist physicians thought that medical knowledge, to deserve that name, had to be based on a theory concerning the constitution of the human body’ (Frede:1987:246). The empiricists regarded this as a mistake and that ‘one should assume instead that medical knowledge was a matter only of experience’ (Frede:246).
For their part, the rationalists claimed that experience-based medicine was impossible, that however many experiences were acquired, of themselves they could not point to any course of treatment. They could never provide knowledge of illnesses based on experience alone, not without reference to correct knowledge of the body. The empiricists argued to the contrary, that the rationalists discovered their knowledge through experience and then added accounts of how the workings of the body would be affected by their proposed cures. They worked in this way, it was sometimes alleged, to distance themselves from those whose education had not equalled their own. It was hoped thereby, to convince patients of their own superior medical capabilities Frede:1987:239/240).
In short, Harald Thorsrud says, the empiricists argued that medical theories of the body were ‘practically useless’ (Thorsrud:2009:196). Sextus Empiricus allied himself in the main with the empiricists, as his name indicates. However, this connection with the Empiric School illustrates for us how Pyrrhonism walks a tightrope between belief and knowledge.
As we have seen, the core of Pyrrho’s insight was that people should not engage with belief systems beyond what is obvious. Empiricism may be thought by some to be exactly that …not entirely obvious, since it involves the simple action of accepting …or believing in, the results of one’s own senses, through experience of the world. It seemed that for Sextus (and as we shall later see, conounter to Descartres) empiricism may have been just a little too confident in handling knowledge to be an approach that it was appropriate for a pyrrhonist to support. For all its apparent willingness to step back from asserting any creed, empiricism can become, Sextus suggested, an approach to knowledge in which people believed – in effect, a creed in itself. Sextus Empiricus objected to this – strongly. A belief, even in empiricism, could lead us astray, he thought (Thorsrud:2009:197, Floridi:2002:7, Frede:987:251/254). As a result, he toyed with the third medical theory of his time – the Methodic School.
Apart from one or two references to it in Outlines of Scepticism (principally Bk 1 Section xxxiv, Annas & Barnes:1994: 62-64 ) Sextus does not develop his attachment to the Methodic School. In fact, there is a marked lack of clarity about this school; it seems to have begun around the 1st century BCE but not to have been serious competition for the other two schools. The Methodic approach to medicine has mystified scholars, historians and even contemporaries such as Galen, for it sought to decry the arguments of both rationalists and empiricists to suggest that ‘direct observation of the patients’ current condition, and that alone, is sufficient to indicate the proper condition’ (Thorsrud:197). In other words, all that a physician needed do to establish how to cure an ill person, was to be clear about the nature of the illness. Any underlying condition the patient might have, will manifest itself in such an examination and no deep experience of medicine is necessary to become a physician. I am summarising heavily here, but this seems to have been the broad position of the methodists.
The problem is that ‘being clear about the nature of the illness’ is of course an important part of what the medical practitioners of the other two schools were trying to achieve. But methodists used it as the whole point and one that can be discovered simply by examining the patient. Hankinson suggests some of the dangers in this approach. He uses the devastating condition of rabies as an example, that in regarding a dog bite as just that, a bite, without any consideration of similar cases in the past, could be catastrophic for the patient (!995: 234-236). Michael Frede devotes a chapter of his Essays in Ancient Philosophy (1987) in a useful attempt to make sense of methodism but suggests in the end that its claim to be a revolutionary development in medical practice largely failed. He concludes that Sextus ‘carefully refrained from fully endorsing Methodism as a skeptical position’ and that ultimately it was traditional empirical practice that happily survived’ (1987:Ch 14: 278).
So to conclude this part of the explanation, Sextus recommends that the Pyrrhonists should step back from definitive questions or statements about the world (such as ‘do Gods exist?’) and allow their senses to receive the evidence for and against – the equipollence (or equivalence ) of the enquiry. They will then be able to participate in debate but only up to the point where belief starts to take over from empirical considerations. Sextus gave an example of this in ‘Against the Ethicists’. In response to the question of whether ‘man is a rational, mortal animal’ he said the Pyrrhonist, sticking entirely to the limitations of what is clear from the evidence, might respond by saying that it is better to say that ‘whatever thing is man, that thing is a rational, mortal animal’ (Bury:1936: 389). In our modern world we might more likely say ‘is it part of the human nature of men and women to be rational and mortal?’ and the Pyrrhonist might answer ‘we do not know what human nature is, but there is evidence to suggest that men and women are rational and mortal’. As a shorthand the Pyrrhonist might go along with the suggestion that this is ‘human nature’ but if there were any consequences of note in using that term, then the Pyrrhonist would quickly revert to their more formal stance. Thus for Sextus Empiricus, Pyrrhonism is to all intents and purposes the same as empiricism and the Pyrrhonist proceeded to function in the empirical fashion; i.e. to know the world though our senses and the sense that we can make of them, always remembering that their findings are provisional and could easily be changed in the light of new evidence or a changed perspective.
It seems clear that what Sextus Empiricus does for Pyrrho’s ideas was to show first that unlike dogmatic scepticism, Pyrrhonism is not just an academic argument; it forms part of humans’ lived experience of the world. Second, he went that extra distance and included the Pyrrhonists’ propensity to include their own statements within the sceptic’s reach, and also stepped back from commitment to belief-inspired epistemological speculation. In doing this he showed that empiricism (in the sense of knowing the world through one’s senses and the sense that one can make of them) is the same as Pyrrhonism. Moreover, if Pyrrhonism, as we have suggested in an earlier chapter, stemmed from the ideas of the Indian Buddhist-like sages that Pyrrho learned from, in the Alexandrian campaign, then it follows that empiricism embodies, to some extent, that ancient Indian epistemology.
We shall need to return to this argument later in the book to see how it can work in modernity. What is now pressing is to determine whether Sextus’ insights survived the ancient and the medieval world in any kind of recognisable form, to have stood and any chance at all in being able to enter into our modern thinking.