Method, viz., Certainty. In this respect is the Cartesian doubt distinguished from the sceptical, the end of which is not the certainty of affirmation and negation, but continual doubt, and thence permanent indifference and indisturbance.[1]
The Cartesian doubt, therefore, in so far as preliminary to the Cartesian Method, is simply equivalent to a resolution to accept such truths as the philosopher might determine to fall within the sphere of Philosophy, on their own evidence, and on that alone.
Such is the nature and end of the Cartesian doubt. The manner in which Descartes avails himself of doubt to accomplish the end of his Method, will be noticed in detail when we come to show how he manifests the reality of knowledge.
From what has been said of the Cartesian doubt its legitimacy is manifest. Doubt of this nature, though perhaps not in an unlimited generality and immediacy, is even obligatory as a means to knowledge, if we would not take our opinions on trust.
But, in the second place, it may be proper at this stage to show what the Cartesian doubt, viewed in its general aspect, involves, in respect of the Principle of Truth and Certainty.
II. This is manifestly the denial of the jurisdiction of authority in the sphere of the true and
- ↑ See the Method, Part III., p. 71; also Part IV.; and the 1st Meditation, passim; compare Hypotyposes of S. Empiricus, Book I., chap. iv.
