ppoint the widely spread belief
that he was in possession of a philosophy more certain than the common one.
The work entitled _Le Monde_, begun in 1630 and almost completed, remained
unprinted, as the condemnation of Galileo (1632) frightened our philosopher
from publication; fragments of it only, and a brief summary, appeared
after the author's death. The chief works, the _Discourse on Method_, the
_Meditations on the First Philosophy_, and the _Principles of Philosophy_
appeared between 1637 and 1644,--the _Discours de la Methode_ in 1637,
together with three dissertations (the "Dioptrics," the "Meteors," and the
"Geometry"), under the common title, _Essais Philosophiques_. To the (six)
_Meditationes de Prima Philosophia_, published in 1641, and dedicated to
the Paris Sorbonne, are appended the objections of various savants to whom
the work had been communicated in manuscript, together with Descartes's
rejoinders. He himself considered the criticisms of Arnauld, printed fourth
in order, as the most important. The Third Objections are from Hobbes, the
Fifth from Gassendi, the First, which were also the first received, from
the theologian Caterus of Antwerp, while the Second and Sixth, collected by
Mersenne, are from various theologians and mathematicians. In the second
edition there were added, further, the Seventh Objections, by the Jesuit
Bourdin, and the Replies of the author thereto. The four books of the
_Principia Philosophiae_, published in 1644 and dedicated to Elizabeth,
Countess Palatine, give a systematic presentation of the new philosophy.
The _Discourse on Method_ appeared, 1644, in a Latin translation, the
_Meditations_ and the _Principles_ in French, in 1647. The _Treatise on the
Passions_ was published in 1650; the _Letters_, 1657-67, in French, 1668,
in Latin. The _Opera Postuma_, 1701, beside the _Compendium of Music_
(written in 1618) and other portions of his posthumous writings, contain
the "Rules for the Direction of the Mind," supposed to have been written in
1629, and the "Search for Truth by the Light of Nature." The complete works
have been often published, both in Latin and in French. The eleven volume
edition of Cousin appeared in 1824-26.[1]

[Footnote 1: Of the many treatises on the philosophy of Descartes those of
C. Schaarschmidt (_Descartes und Spinoza_, 1850) and J.H. Loewe, 1855, may
be mentioned. Further, M. Heinze has discussed _Die Sittenlehre des
Descartes_, 1872; Ed. Grimm, _Descar