o determine their
value.

Principle of doubt.

Certainty of the thinking self.

_The Philosophy of Descartes._--Descartes was, in the full sense of the
word, a partaker of the modern spirit. He was equally moved by the
tendencies that produced the Reformation, and the tendencies that
produced the revival of letters and science. Like Erasmus and Bacon, he
sought to escape from a transcendent and unreal philosophy of the other
world, to the knowledge of man and the world he lives in. But like
Luther, he found within human experience, among the matters nearest to
man, the consciousness of God, and therefore his renunciation of
scholasticism did not end either in materialism or in that absolute
distinction between faith and reason which inevitably leads to the
downfall of faith. What was peculiar to Descartes, however, was the
speculative interest which made it impossible for him to rest in mere
experience, whether of things spiritual or of things secular, which made
him search, both in our consciousness of God and our consciousness of
the world, for the links by which they are bound to the consciousness of
self. In both cases it is his aim to go back to the beginning, to
retrace the unconscious process by which the world of experience was
built up, to discover the hidden logic that connects the different parts
of the structure of belief, to substitute a reasoned system, all whose
elements are interdependent, for an unreasoned congeries of opinions.
Hence his first step involves reflection, doubt and abstraction. Turning
the eye of reason upon itself, he tries to measure the value of that
collection of beliefs of which he finds himself possessed; and the first
thing that reflection seems to discover is its accidental and
unconnected character. It is a mass of incongruous materials,
accumulated without system and untested. Its elements have been put
together under all kinds of influences, without any conscious
intellectual process, and therefore we can have no assurance of them.
In order that we may have such assurance we must unweave the web of
experience and thought which we have woven in our sleep, that we may
begin again at the beginning and weave it over again with "clear and
distinct" consciousness of what we are doing. _De omnibus dubitandum
est._ We must free ourselves by one decisive effort from the weight of
custom, prejudice and tradition with which our consciousness of the
world has been overlaid, that