Descartes Revisited

Descartes is among my least favorite of those conventionally termed great philosophers. My treatment to date has been mainly limited to a few dismissive remarks. Here I’d like to add a few “historiographical” points of demarcation.

Insofar as there is general consensus among scholars, Descartes (1598-1650) first and foremost has claim to fame as a very influential promoter of something recognizably close to modern scientific method. He is often credited with the invention of analytic geometry, based on an early recognition of the systematic isomorphism between geometry and algebra. Galileo (1564-1642) had already taken up an approach to natural science based on mathematical analysis, which Descartes enthusiastically adopted. Descartes particularly promoted a methodology based on clear and distinct ideas, which he held to give certain knowledge. He advocated an orderly progression from the simple to the complex.

On a broad social level, Descartes is remembered for promoting the independence of scientific investigation, particularly from the doctrinal concerns of the Catholic Church. But he was also a religious thinker. While confessing in a private letter that he did not literally believe various details of received scripture, he was very engaged with proofs of the existence of God.

Numerous scholars have pointed out that outside the domains of mathematics and natural science, Descartes in many ways remained close to the Latin scholasticism of which he has been commonly regarded as the slayer. In Descartes and the Modern Mind (1952), for example, Albert Balz argued at length that the thought of Thomas Aquinas was an essential precursor to Descartes. I note that Augustine had already emphasized the importance of the interpretive role of reason, even in matters of faith. On Aquinas’ account, God gives us not only revelation, but also the natural light of reason. In Summa Contra Gentiles, Aquinas addressed questions of philosophy and theology entirely from the point of view of that “natural light”, while aiming to show that the natural light of reason independently leads to many of same truths he attributed to revelation. Descartes makes great use of a similar concept of the natural light of reason.

Both Descartes and Aquinas thought the natural light of reason, properly understood, gives us truths, full stop. I think it gives us invaluable criteria for judgment and interpretation, while always in principle leaving room for discussion about what conclusions should be drawn. I also think the “natural light” itself comes to us in degrees, and is never a simple or unproblematic possession.

A different strand of Latin scholastic thought tended to claim that all human knowledge originates in sensible images, while attributing such a view to Aristotle. (I think this is overly strong, and that Aristotle only meant to defend the pragmatic value of sensation against Platonic skepticism about all deliverances of sense.) Descartes famously argued that sensible images are not the only source of knowledge, and I think that is true, as far as it goes.

Here is where Descartes’ theses about clear and distinct ideas come into play. A methodological discipline based on examining whether our ideas are clear and distinct is an important source of human knowledge. Again, this much I can agree with, but I think clarity and distinctness are relative criteria and not absolutes. As relative criteria, they have been implicitly employed by most if not all serious thinkers. I take such evaluations to have been a major implicit concern of Platonic and Aristotelian dialectic, which in part aims to discern meanings that are more clear and distinct.

Descartes effectively claimed that clarity and distinctness are absolute, decidable properties of ideas. One of the broadly scholastic views he sharply criticized was that our best knowledge of sensible things is only “probable”. Descartes claimed that the results of his methodological analyses were certain, in the same way that mathematical conclusions follow with certainty from their premises. This goes well beyond the claim that there is practical value in such methodology.

Building on arguments of Augustine and Avicenna, he also famously gave great importance to the claim that immediate contents of the mind give evidence of unconditional certainty of the abstract existence of something. The very possibility that I could be deceived implies the abstract existence of an abstract something that could be deceived. Further, if something in any way appears to me to be such and such — even if I am wrong about all the details — independent of all the details, the barest fact of the appearance implies that some appearance generically “exists”.

The “I” that is in this way proven to exist and the appearance that is proven to exist are both extreme abstractions. Even Descartes did not claim that either of these existences by itself gives us any further knowledge. From this basis alone, I could still be entirely mistaken about the kind of being that I am, and about every detail of what appears to me to be the case. In spite of the famous Cartesian doubt, Descartes actually wanted to makes strong claims of certainty and to refute skepticism. Many readers have concluded, though, that he opened the door for a new, more global form of skepticism, because what he clearly establishes as certain seems so utterly lacking in content.

I would hasten to add that unreasonable, excessive skepticism about human knowledge is best refuted by successful achievements of goals in real-life situations. Only a hypocrite could claim to live in the world with no well-founded beliefs whatsoever. The ancient Skeptics were only “skeptical” about theoretical accounts of things, not about practical concerns of everyday life.

By setting the bar too high and aiming at absolute certainty, Descartes actually opened the door for more radically subjectivist views that no one in the ancient world would have taken seriously (and not just because ancient people were naive). At the same time, he was very impatient with “dialectic”, and tended to foreshorten discussions of meaning and interpretation, in favor of claims that certain contents are unequivocally clear and distinct. Thus the ultimate result of his thought oscillates unstably between extremes of “Cartesian” skepticism and dogmatism.

Another point on which Descartes has been very influential is his strong representationalism. For Descartes, strictly speaking we never have practical knowledge of things in the world, only knowledge about contents of our mental representations, insofar as they are clear and distinct. In particular, we only know bodies through our mental representations of them. Rather than consisting in an interpretive stance of a situated being in the world, the Cartesian cogito achieves its purely subjective certainty in a way that is supposed to be peculiarly “outside” the real world altogether.

Unlike the representationalism of Locke, which is grounded in a kind of empirical psychology, that of Descartes is closely bound up with an ontological mind/world dualism more radical than anything Plotinus, Augustine, or Avicenna ever contemplated. For Plotinus, Augustine, and Avicenna, the soul was a very special kind of “something” existing in the real world, even if for Plotinus and Augustine it was not a “subject” in the sense of something underlying something else. For Locke — the other great early modern promoter of representationalism — our mental worlds are ultimately contained within the natural world. For Descartes, there is the world and there is the soul, and never the twain shall meet. The soul has its own mental world where it seems to relate directly only to God, and human knowledge occurs only in that mental world.

It is due to this unprecedentedly radical mind/world dualism of Descartes, I think, that virtually no one — even among his admirers — wants to uphold his metaphysics. This is an extreme example of what Hegel called “alienation”.

Hegel on Skepticism

The next shape of self-consciousness after “Stoicism” in Hegel’s Phenomenology is “Skepticism”. H. S. Harris in his commentary thinks some of Hegel’s remarks apply specifically to Carneades, perhaps the best known “Academic” Skeptic, who shocked the Romans by arguing for opposite theses on alternating days, as an exercise on Platonic dialectic. Carneades also wrote a work arguing in detail against the great early Stoic Chryssipus. Although I like to stress the less textually obvious role of Aristotelian dialectic in Hegel’s work, Hegel’s explicit remarks emphasize a kind of Platonic dialectic with Skeptical inflections (see Three Logical Moments).

For Hegel, neither pure Understanding — which excels in clarity, utility, and systematic development but tends toward dogmatism — nor a skeptically inclined Dialectic, whose movement undoes everything that is apparently solid — is adequate to characterize what he wants to call Thought. Thought ought to involve a sort of Aristotelian mean that combines the insights of both.

Hegel writes, “Skepticism is the realization of that of which Stoicism is merely the notion, and is the actual experience of what freedom of thought is…. [I]ndependent existence or permanent determinateness has, in contrast to that reflexion, dropped as a matter of fact out of the infinitude of thought” (Baillie trans., p. 246). “Skeptical self-consciousness thus discovers, in the flux and alternation of all that would stand secure in its presence, its own freedom, as given by and received from its own self…. [This] consciousness itself is thoroughgoing dialectical restlessness, this melĂ©e of presentations derived from sense and thought, whose differences collapse into oneness, and whose identity is similarly again resolved and dissolved…. This consciousness, however, as a matter of fact, instead of being a self-same consciousness, is here neither more nor less than an entirely fortuitous embroglio, the giddy whirl of a perpetually self-creating disorder” (pp. 248-249).

Harris comments, “[T]he Stoics had to be taught by the Sceptics that no Vorstellung [representation] (not even that of the great cosmic cycle) could comprehend Erscheinung [appearance]” (Hegel’s Ladder I, p. 393). “[Skepticism] knows that ‘language is truer’… than the simple assumption that truth is the name of an extralinguistic Sache [thing or content]” (ibid).

“The Sceptic ideal is to be untroubled in the face of the sensory flux. Sceptical reason tells us not to worry about what we cannot help” (ibid). But “Far from behaving like one who is undisturbed, [Carneades] enjoys being an active disturber; and on the practical side his life has to be controlled by the felt motive actually present at a given moment” (p. 394). “Achieving ‘suspension of judgment’, by setting whatever contingent arguments one can discern in the whirl against those that someone else offers, is a cheat. The Sceptic lives in the world, and allows himself to be guided by senses which he says we ought not to trust” (ibid).

“Every effort the Stoic makes to realize his freedom is tantamount to a serf’s fantasy that he really owns the land” (p. 395). “The Sceptic is a laughing sage because he has the Stoic to laugh at. We laugh at both of them” (ibid).

“[The Skeptic] has not recognized that the [self] he identifies with is only a formal ideal by which the concretely actual self can measure itself. Nobody is that ideal self. No finite consciousness can be that self (by definition). There is no Lord walking the earth: not the one that the serf fears; not the Stoic who thinks he is free; and not the Sceptic who knows what thinking is, and what it is not” (p. 396).


Foundationalism is the mistaken notion that some certain knowledge comes to us ready-made, and does not depend on anything else. One common sort involves what Wilfrid Sellars called the Myth of the Given.

Certainty comes from proof. A mathematical construction is certain. Nothing in philosophy or ordinary life is like that. There are many things we have no good reason to doubt, but without proof, that still does not make them certain.

In life, high confidence is all we need. Extreme skepticism is refuted by experience. It is not possible to live a life without practical confidence in many things.

Truth, however, is a result, not a starting point. It must be earned. There are no self-certifying truths, and truth cannot be an unexplained explainer.

In philosophy, we have dialectical criticism or analysis that can be applied from any starting point, then iteratively improved, and a certain nonpropositional faith in reason to get us going. All we need is the ability to question, an awareness of what we do not know, and a little faith. We can always move forward. It is the ability to move forward that is key. (See also Interpretation; Brandom on Truth; The Autonomy of Reason.)

Stoicism, Skepticism

Brandom makes interesting connections between Hegel’s rather idiosyncratic discussion of Stoicism and Skepticism in the Phenomenology and the preceding discussion of Mastery. Stoicism and Skepticism for Hegel each in a different way reflect aspects of Mastery’s attitude that wants to claim total independence.

Hegel’s criticism of Stoicism in this context is rather different from my previously expressed issues with its foundationalism, claims of a completed system, and what the ancients called its dogmatism. My remarks probably apply more to the system of Zeno and Chrysippus, whereas Hegel’s apply more to the narrower ethical concerns of someone like Epictetus.

Zeno and Chrysippus are known only from references in other authors; none of their original works survive. Surviving references to early Stoic teaching often tend to be somewhat anonymous and generic. The details of the system are quite fascinating and worthy of study in their own right (see the collected fragments in Long and Sedley, The Hellenistic Philosophers; also Sambursky, Stoic Physics; Mates, Stoic Logic; and Nussbaum, Therapies of Desire).

Ancient Skepticism is also quite worthy of study in its own right. In addition to fragments, a number of works by the late author Sextus Empiricus survive. Ancient skeptics were mainly skeptical about theoretical developments. (The more extreme skepticism many modern authors have worried about in the third person seems to be a post-Cartesian development.)

Brandom says Hegel’s Stoics and Skeptics both refuse the experience of error that is crucial to the elicitation of conceptual content. On his reading, Hegel’s Stoic in, say, refusing to recognize physical pain, is both just being stubborn and refusing to address what turn out to be incompatible commitments, effectively denying the reality of the object in order to maintain the independence of consciousness at all cost. The Skeptic is just refusing to make any commitments at all, which is another attempt to maintain the independence of consciousness at all cost. Hegel’s point is that this attitude of wanting to maintain the total independence of consciousness from anything other is unsustainable.