Radical scepticism has a good claim to be both the longest lasting tradition in philosophy and the consistently least popular. There’s a lot to be said for it.
By radical scepticism I mean scepticism that is in the grip of an infinite regress, like the ‘why?’ ‘…’ ‘why?’ ‘…’ ‘why?’ … of a child in the process of discovering philosophy — which is also, not coincidentally, the ‘why?’ ‘…’ ‘why?’ ‘…’ ‘why?’ … of a child discovering radical scepticism. In western philosophy this infinite regress is first discussed by Sextus Empiricus (2nd
According to the mode deriving from dispute, we find that undecidable dissension about the matter proposed has come about both in ordinary life and among philosophers. Because of this we are not able to choose or to rule out anything, and we end up with suspension of judgement. In the mode deriving from infinite regress, we say that what is brought forward as a source of conviction for the matter proposed itself needs another such source, which itself needs another, and so ad infinitum, so that we have no point from which to begin to establish anything, and suspension of judgement follows.
This passage is from Sextus’s Outlines of Pyrrhonism, so named after Pyrrho (c.360-270 BC). Although Pyrrho’s works do not survive, Sextus thought of himself as a disciple of Pyrrho. For this reason, I shall use the words ‘Pyrrhonian scepticism’ or ‘radical scepticism’ to apply to any philosophy that does not escape an infinite regress.
Incidentally, some scholars have pointed out similarities between aspects of early western scepticism (as found in Sextus Empiricus) and the Buddhism that Pyrrho may have encountered when, according to Diogenes Laertius, he travelled to India in the army of Alexander the Great. However, whether or not Pyrrho and Sextus were influenced by Buddhism, it is not hard to imagine an infinite regress arising independently in the earliest stages of different philosophical traditions in unconnected parts of the world and, indeed — as we will see — this seems to have been the case.
Some scholars have pointed out similarities between aspects of early western scepticism and Buddhism.
Contemporary philosophers, who will agree with each other on very little else, tend to agree that it is one of the defining characteristics of philosophy that it should examine its own foundations. Thus, for example, philosophers have often pointed out that it is not part of mathematics to ask ‘what is mathematics?’ and it is not part of natural science to ask ‘what is natural science?’ However, it is part of philosophy to ask ‘what is philosophy?’ For philosophy is self-reflective: it looks at its own foundations and asks ‘why?’ Radical scepticism is this philosophical self-reflection carried to its logical end, or rather its logical inconclusion.
However, the same philosophers who emphasise the self-reflective character of philosophy often have a very negative view of radical scepticism and assume that one of their first duties as philosophers to defeat it. The worry is perhaps that — if we are stuck with the same infinite regress as preoccupied Pyrrho — then scepticism would seem to gainsay any notion of philosophical progress. This was the worry that lay behind Kant’s comparison of sceptics to nomadic barbarians, ever threatening to destroy the civilized achievements built up by their non-sceptic colleagues.
The idea that philosophy progresses is an idea that dates to the Enlightenment; and ever since the Enlightenment those philosophers who believe in philosophical progress are often those philosophers who cast envious eyes at natural science.1 For science, most would agree, does progress. Moreover, as was first pointed out by Pierre Bayle in the late seventeenth century, science, unlike philosophy is unperturbed by radical scepticism.
Yet since radical scepticism still exists, as a live philosophical concern — there is no universally agreed method by which it can be vanquished, nor even a commonly agreed method — it is perhaps time to call into question the notion that philosophy does progress (at least in the same manner of natural science).
Another, older, reason for mistrust of radical scepticism is what is seen as its ridiculous impractical unworldliness. This was exemplified in the ancient world in legends about Pyrrho’s extreme impracticality. These stories were relished all the more in that Pyrrho and his followers believed that their stance was of practical benefit, providing a guide as to how to live. They believed that suspending judgement about any claim to certain knowledge was conducive to peace of mind, to ataraxia (detached serenity).
A rhetoric of slowness and speed has been used by philosophers since the ancient periods to characterise and assess different ways of life.
Few were convinced by Pyrrho’s prescription, but — beyond laughter and ridicule — the question of why it was intuitively unconvincing was not directly addressed. It was not until the work of David Hume that an answer was implicitly given. Hume pointed out that in our everyday life we are largely reliant on inductive reasoning in which certainty plays no part. Rather we have faith that in some measure the future will resemble the past. The implication, against Pyrrho, is that we do not need to suspend judgement, for unavoidably in much of our everyday decision-making we rely not on deductive reasoning but on faith. (I here set aside questions of the nature and extent of Hume’s own scepticism.)
Hume pointed out that in our everyday life we are largely reliant on inductive reasoning in which certainty plays no part.
Implicitly, Heidegger also answered the question of why the prescription was unconvincing. He argued that western philosophy (since the pre-Socratics) has, without justification, tended to assume that metaphysics and epistemology comprise the highest branches of the discipline. Pyrrho’s prescription for ataraxia is a prime example of this. Yes, Pyrrho was concerned with practice but, conforming to Heidegger’s thesis, he tended to assume that taking the correct approach in epistemology would act as a starting point to clear away problems in the practical sphere. Herein lies his impracticality.
It may therefore be of interest to see how radical scepticism manifests itself in a philosophical tradition that developed independently of western philosophy and which does not elevate metaphysics and epistemology to the highest level. The following anecdote about the Chinese sceptic Zhuangzi (late 4th
century BC) provides an example of radical scepticism within a fundamentally different context.
Once Zhuangzi dreamt he was a butterfly, a butterfly flitting and fluttering around, happy with himself and doing as he pleased. He didn’t know he was Zhuanzi. Suddenly he woke up and there he was, solid and unmistakable Zhuangzi. But he didn’t know he was Zhuangzi who had dreamt he was a butterfly, or a butterfly dreaming he was Zhuangzi. Between Zhuangzi and a butterfly there must be some distinction! This is called the Transformation of Things. (Zhuangzi, §2)
In this story, Zhuangzi has to decide between whether he is more likely to be Zhuangzi or a butterfly. He asks himself what seems to be more immediately likely? He does not suspend judgement, as recommended by ancient Greek sceptics; but yet, as is apparent throughout the Zhuangzi (the collection of stories about this philosopher), he retains an awareness of his fallibility — an awareness that arises within his everyday life. It is this wariness towards certainty, whilst yet accepting the need to make choices, that benefits the everyday life of the sceptical philosopher.
But he didn’t know he was Zhuangzi who had dreamt he was a butterfly, or a butterfly dreaming he was Zhuangzi.
It should, however, be stressed that in Zhuangzi, as much as in Sextus Empiricus, there is the same awareness of scepticism’s infinite regress. This is evident in the following conversation related in the Zhuangzi.
Nieh Ch’üeh asked Wang Ni, “Do you know what all things agree in calling right?”
“How would I know that?” said Wang Ni.
“Do you know that you don’t know it?”
“How would I know that?”
“Then do things know nothing?”
“How would I know that? …” (Zhuangzi, §2)
In summary the comparison of radical scepticism in Chinese and western philosophy suggests again that the impracticality of achieving ataraxia is not intrinsic to radical scepticism but rather is intrinsic to the impractical elevation of metaphysics and epistemology above all other branches of philosophy.
Having defended radical scepticism from the criticisms that it is an impediment to philosophical progress and that it is ridiculously impractical, it should, more positively, be said that without any belief in philosophical progress, there is much interesting and useful work that the sceptic is well-equipped to do.
For example, without baggage (without presuppositions) the sceptic may be well equipped to discover the presuppositions underlying both everyday judgements and other disciplines of inquiry. Indeed, without presuppositions the sceptic is less likely than Kant to become entangled in debates about appearance and reality.2 But although this is useful work, as conducted by the sceptic, it is not an exercise that is progressive in an Enlightened sense — for the sceptic will have no reason to believe that in the future these presuppositions will not change.
The overall aim of Descartes’ philosophy is to found science on a secure and absolutely certain footing. Without that anything built by science would be open to doubt following from the weakness of its foundation.
Besides Kant, there are a number of other critics of metaphysics (as the study of ultimate reality) who might have benefitted from a starting point of radical scepticism: for example, A.J. Ayer, who argued that there are only two kinds of meaningful statement, those that are true by definition and those that can be verified by experience. Ayer faced the criticism that in making this claim it was unclear as to what foundation he himself was standing on. But if his starting point had been radical scepticism, then instead of being confounded by the question, ‘what foundation do you yourself stand on?’ he might in good conscience have admitted, ‘None, whatsoever. My claim applies only to statements made within inquiries outside of philosophy, but, as for myself, I have no skin in those games.’
Rorty argued that philosophy’s attempt to mirror a mind-independent nature is doomed to failure.
Another critic of metaphysics who might have benefitted from embracing scepticism’s infinite regress is Richard Rorty. Rorty argued that philosophy’s attempt to mirror a mind-independent nature is doomed to failure. (G.H. Lewes put forward a similar argument in the nineteenth century.) Rorty suggested that, with this realisation, philosophy’s raison d’être, as an autonomous discipline, falls away and as a live concern it falls into desuetude.
But the sceptic might agree with Rorty’s criticisms of philosophy’s attempts to mirror a mind-independent nature, whilst at the same time pointing out that scepticism’s infinite regress remains, untouched by his criticisms.
Therefore, at least one (non-metaphysical) part of philosophy remains — and, whilst philosophy is maximally self-reflective, always will.
Kant is not usually associated with scientism but I suspect that he may belong to this group, in that there are parallels between his systematic categorising and that of Carl Linnaeus whose achievements were known, at least by reputation, to every educated person at the time. ↩︎
‘Without the presupposition [of the “thing in itself,”] I was unable to enter into [Kant’s] system, but with it I was unable to stay within it’ – Jacobi. This seems to be the essence of a great number of subsequent criticisms of Kant. However, the radical sceptic would say nothing of the “thing in itself.” ↩︎