ns from the Principles'
(Edinburgh, 1853; 6th ed., Blackwoods, Edinburgh and London, 1879). See
also, English translations of portions of his philosophical works, by W.
Cunningham (1877), Lowndes (1878), Mahaffy (1880), Martineau (1885),
Henry Rogers, Huxley, and L. Stephen.

For his Life, see 'Vie de Descartes,' by Baillet (2 vols. 1691);
'Descartes sa Vie,' etc., by Millet (2 vols. 1867-71); 'Descartes and
his School,' by Kuno Fischer (English translation, 1887).

OF CERTAIN PRINCIPLES OF ELEMENTARY LOGICAL THOUGHT

From the 'Discourse on Method'

As a multitude of laws often only hampers justice, so that a State is
best governed when, with few laws, these are rigidly administered; in
like manner, instead of the great number of precepts of which Logic is
composed, I believed that the four following would prove perfectly
sufficient for me, provided I took the firm and unwavering resolution
never in a single instance to fail in observing them.

The _first_ was never to accept anything for true which I did not
clearly know to be such; that is to say, carefully to avoid precipitancy
and prejudice, and to comprise nothing more in my judgment than what was
presented to my mind so clearly and distinctly as to exclude all ground
of doubt.

The _second_, to divide each of the difficulties under examination into
as many parts as possible, and as might be necessary for its adequate
solution.

The _third_, to conduct my thoughts in such order that, by commencing
with objects the simplest and easiest to know, I might ascend by little
and little, and as it were step by step, to the knowledge of the more
complex; assigning in thought a certain order even to those objects
which in their own nature do not stand in a relation of antecedence and
sequence.

And the _last_, in every case to make enumerations so complete, and
reviews so general, that it might be assured that nothing was omitted.

The long chains of simple and easy reasonings by means of which
geometers are accustomed to reach the conclusions of their most
difficult demonstrations, had led me to imagine that all things to the
knowledge of which man is competent are mutually connected in the same
way, and that there is nothing so far removed from us as to be beyond
our reach, or so hidden that we cannot discover it, provided only we
abstain from accepting the false for the true, and always preserve in
our thoughts the order necessary for the deduction of o