UC Davis Philosophy 22 Lecture Notes

The Skeptical Crisis in European Philosophy


For a comprehensive account of these developments, especially those mentioned in the last paragraph, see Richard H. Popkin, The History of Scepticism from Erasmus to Spinoza, University of California Press (1979).

For more on ancient skepticism, see the entry in the Stanford Encyclopedia of Philosophy.

For more on Pyrrho, see the entry in the Internet Encyclopedia of Philosophy


The Renaissance was fueled by the re-appearance in Europe of a great many ancient philosophical texts that had been all but forgotten during the Middle Ages. Among these works were several compilations of skeptical arguments by Sextus Empiricus, including his Outlines of Pyrrhonism. Sextus was a late representative of "Pyrrhonian" skepticism, which prescribed the supension of judgment in all matters that go beyond the appearances. The teachings of Pyrrho of Elis, who lived in the third century B.C., can be summed up in his slogan "No more this than that." Pyrrho's idea was that when any given matter is not apparent, the reasons for and against the truth of the matter cancel each other out, leaving neither side at an advantage. By refusing to make a judgment on any such matter, a person is able to attain freedom from the mental strife that comes with a futile search for the truth.

Pyrrho's pronouncement was sweeping in its scope. To make it plausible, his followers devised arguments to discredit the many ways which had been used to justify beliefs in what is not apparent. It was easy enough to discredit the senses, for they present to the mind nothing but appearances. If we ask whether a thing really is the way it appears to be, we are always confronted with conflicting appearances. A piece of paper looks white to one man and yellow to someone suffering from jaundice. The Pyrrhonians presented myriad such examples and even went so far as to categorize them by type (or "modes"). But no matter how the conflicts arise, the most that can be done with the senses is to present the mind with alternatives, from which we pick out one appearance or set of appearances as representing what really is.

But how, it must then be asked, does one set of appearances get its position of superiority against the others? It could only be if we could find something to serve as a judge granting authority to one set of appearances over another. Now the skeptics argued that this judging instrument, the criterion, cannot be one or more of the appearances at issue, for this would be to beg the question. The criterion must be found outside the appearances that are at odds with each other. For example, it could be claimed that the way something appears to the healthy person, not the jaundiced person, is the way it really is. The healthy person, then, is the criterion.

But the skeptic asks, naturally enough, why we should accept the healthy person as the judge of appearances. Perhaps it would be answered that the healthy person's senses function normally, and that normally functioning senses detect the real color of things, while the senses of the jaundiced person see everything as yellow because of their disease. At this point, the skeptic would ask why we should accept that normally functioning senses detect reality any better than abnormally functioning senses. That is, we need a criterion to judge the use of the healthy person as the criterion. Note that no appeal can be legitimately be made to the original appearances, for they are still at issue. Nor can appeal be made to the healthy person as a judge of whether healthy people's senses detect things as they really are. In both cases, the question in dispute would be begged.

If we suppose that some other criterion could be found, the same kind of challege could be raised. So the skeptic concludes that a dispute over the reality of things beyond the appearances cannot be settled satisfactorily. Whenever a criterion is proposed, it is open to challenge. The challege cannot be met by appeal to the criterion under dispute, or to that which the criterion is supposed to decide. So there is no end to the attempt to adjudicate a dispute by appeal to a criterion. This is what has come to be known as "the problem of the criterion."

As the ancient Skeptics realized, the same sort of problem applies to religious claims about reality. Opinions about the gods go far beyond the appearances. Different religions give conflicting accounts of the reality of that which appears to us through the senses.

Around all matters of religion and theology also, there rages violent controversy. For while the majority declare that gods exist, some deny their existence. . . . And of those who maintain the existence of gods, some believe in the ancestral gods, others in such as are constructed in the Dogmatic systems--as Aristotle asserted that God is incorporeal and "the limit of heaven," the Stoics that he is a breath which permeates even things most foul, Epicurus that he is anthropomorphic, Xenophanes that he is an impassive sphere." (Outlines of Pyrrhonism, Book III, 218
Of these and many other disputes we can add that the problem of the criterion applies. They cannot be settled by appeal to the appearances themselves; a criterion is needed. The criterion cannot be pre-evident, for then the existence and nature of gods would be pre-evident, while the disagreement shows it is not. On the other hand, if the criterion is non-evident: "for he who asserts this will be driven into circular reasoning when we keep demanding proof every time for the non-evident fact which he produces as proof of the one last propounded. Consequently, the existence of God cannot be proved from any other fact" (Outlines of Pyrrhonism, Book III, 8).

In the period after the flourishing of the Pyrrhonians, the Roman Catholic Church became the dominant religion in Europe. In its long history, the Church had been party to numerous doctrinal disputes, and many beliefs which had been held for a long time by large numbers of people eventually were declared heretical. Disputes were settled by appeal to the authority of the Church itself, often as the result of Church councils in which both sides were vigorously argued. Of course, the authority of the Church was not presented as being arbitrary. Appeals were made to scripture and tradition as, in Sextus's language, criteria of the criterion.

In the fifteenth century, the Church faced the sternest test ever presented to its authority. Martin Luther (1483-1546) challeged a number of Church doctrines, but more importantly, he challenged the very authority of the Church itself to decide matters of Christian belief. Against Church authority, he pitted the conscience of the individual Christian believer, which he held to be capable of discerning the truth in religious matters without the need for external guidance.

Unless I am convicted of error by the testimony of Scripture or (since I put no trust in the unsupported authority of Pope or of councils, since it is plain that they have often erred and often contradicted themselves) by manifest reasoning I stand convicted by the Scriptures to which I have appealed, and my conscience is taken captive by God's word, I cannot and will not recant anything, for to act against our conscience is neither safe for us nor open to us." (Luther's statement at the Diet of Worms, 1521)
Tradition was scorned by Luther, in favor of direct reading of scripture, which, after all, is the word of God. But as defenders of the Catholic Church pointed out, there are many ways of interpreting the text of the holy books, and without the authority of the Church to determine the correct reasoning, no interpretation would be better than any other. Each side argued in this sort of way in favor of their criteria, but as the Pyrrhonian could have pointed out in advance, the argument could not be settled because it is another instance of the problem of the criterion.

It was in this environment that the works of Sextus and others were re-discovered in Europe. In 1562, Outlines of Pyrrhonism was translated into Latin, which allowed Sextus's work to become widely known. There eventually arose a "Pyrrhonian crisis" among European philosophers, especially in France. As Pyrrhonian skepticism began to take hold among the philosopers, it became incumbent upon the anti-skeptics to devise a defense against the collapse of belief. As we will learn shortly, the most important anti-skeptical philosopher was René Descartes. He was concerned not with religous issues, but with the justification of the kind of scientific claims epitomized by the work of Galileo. Before turning to Descartes, however, we will set the stage by taking a look at a sixteenth century French philosopher, Michel de Montaigne, who attempted to turn Pyrrhonian skepticism to the service of the Catholic faith.


[ Previous Lecture Notes: Early Modern Scientists | Next Lecture Notes: Montaigne | Lecture Notes Menu | Philosophy 22 Home Page ]