Historically, the phenomena that have been assembled under the label ‘scepticism’ have depended primarily upon whichever constructive proposals were on offer at any given time, with the result that scepticism has often been ‘parasitical’ upon dogmatism.4 Without any further specification, therefore, ‘scepticism’ is thus just as unclear a term as ‘philosophy’ or ‘science’. Abstractly formulated, ‘scepticism’ can be regarded as a destructive system of assertions formulated with the intention of systematically dislodging some given piece of constructive theorising. Accordingly, the sceptic philosophises from a position of opposition, following a negative programme that presupposes the existence of a positive programme to be used as a foil. This is why the ancient master sceptic Sextus Empiricus, whom we shall encounter again and again throughout this study, determined the ‘activity’ (ἀγωγή) of sceptical philosophising as ‘an ability to set out oppositions among things which appear and are thought of in any way at all’ (δύναμις ἀντιθετικὴ φαινομένων τε καὶ νοουμένων καθ´ οἱονδήποτε τρόπον).1 The sceptic, therefore, avowedly pursues a primarily practical (and thus no longer merely destructive) aim insofar as she attempts to finally make good on the salvific promise of ‘tranquillity’ (ἀταραξία), just like the adherents of rival Hellenistic schools. Yet she does so by seeking eudemonia not in contemplation of the eternal, as did Plato and Aristotle, but in the life and customs (νóμοι) of the community. These customs do not admit of a philosophical legitimation but stand for ‘what has to be accepted, the given’, as they would later for Wittgenstein.
Although one could cite many contemporary philosophers, such as Richard Rorty, Robert Fogelin or Michael Williams, who self-consciously theorise in the tradition of ancient scepticism, none of these authors seriously take up its soteriological dimension. Yet a much more marked and important difference between ancient scepticism and the contemporary scepticism debate (especially as conducted within analytic epistemology) stems from a feature of post-Cartesian philosophy that I have already mentioned, namely that scepticism came to adopt a systematic function within epistemology.
Since Descartes, that is, it has become customary to incorporate scepticism into epistemology’s motivation, a tactic which led Descartes himself to introduce the idea of a constructive scepticism. By a theory’s ‘motivation’, I understand the set of reflections that result in the theory’s execution but cannot themselves be justified through the theory’s (yet to be established) theoretical resources. Motivation is accordingly an operation that conditions a theory, while justification – i.e. the giving of reasons – is already conditioned by a theory. Justification always comes after the fact of motivation.
Descartes made a purely methodological use of scepticism in a way that would prove decisive for modern epistemology. He thereby became (among other things) the precursor of what I shall from now on, following Dietmar Heidemann, label integrative anti-scepticism. By this term, I mean to pick out any anti-sceptical strategy that regards scepticism as the condition of the intelligibility of the basic question of epistemology: the question of the nature of knowledge. Integrative anti-scepticism sets out from the assumption that the project of modern epistemology can be made comprehensible (intelligible) in the first place – in other words, can be motivated – only given a confrontation with the problem of Cartesian scepticism.
By Cartesian scepticism, I understand the project of formulating sceptical scenarios that have the potential to trigger hyperbolic doubt. The relevant scenarios exercise this potential by showing how the world as a whole could be utterly other than it appears, such that most, or even all, of our beliefs about the world would stand revealed as false. Clearly, this sense of ‘Cartesian scepticism’ does not designate Descartes’ own ego-logical or theological anti-sceptical strategy, which instead reverses the pattern described above and attempts to deploy sceptical scenarios as a foil for its own constructive programme.
When exploited by an integrative anti-scepticism, Cartesian scepticism functions as a condition of modern epistemological theorising: the strategy in question integrates scepticism into the project of epistemology in the sense that, by making a case for the impossibility of knowledge as conceived by a given philosophical theory, it is scepticism which first opens up the space for epistemology’s basic questions. However, the business of highlighting the precariousness of knowledge serves only as a spur to secure it against the spectre of its impossibility, and thus to overcome scepticism. When it plays this role, the problem of Cartesian scepticism is therefore invoked purely as something to be overcome, specifically by casting it in the form of a methodological scepticism. The latter arises through the confrontation with the possible impossibility of knowledge and goes on to clarify how knowledge is possible after all. In this way, the possibility of knowledge is to be rendered intelligible in and through the thematisation of its potential impossibility.
This broad anti-sceptical strategy makes room for reflection on the conditions of epistemological theorising by assuming from the start that Cartesian scepticism is a condition of the intelligibility of epistemology itself. It thereby leads to the insight that epistemology is a second-order theory, a theory tasked with thematising the conditions of possibility of first-order cognition. Hence epistemology claims to be reflexive insight into the structure of knowledge and, as such, to constitute knowledge itself – specifically, second-order knowledge. The content of this second-order knowledge is then first-order knowledge, while the content of first-order knowledge, at least in paradigmatic cases of empirical knowledge, is everything that is the case independently of its being known.
This does not mean that empirical knowledge has to be flanked by an explicit epistemology: one can know all manner of things without knowing, in addition, how it is possible to know anything at all. This is why epistemology requires a motivation: there are conditions of its introduction, namely, whichever conditions lead first-order knowledge to reflect on itself. In other words, the transition from a first-order to a second-order theory – i.e. the operation of reflection – always has to be motivated. After all, knowledge is primarily intentional and thus oriented to objects that it does not necessarily have to thematise as objects of knowledge. When I know that there is a glass in front of me, I do not ipso facto already know that I know that there is a glass in front of me. Taking this further step requires a change in theoretical attitude, and thus a certain provocation.
For an extensive account, see Gabriel, Antike und moderne Skepsis: Zur Einfuhrung. ↩