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LEIBNIZ, GOTTFRIED WILHELM (b. Leipzig,
Germany, 1 July 1646; d. Hannover, Germany,
14 November 1716), mathematics, philosophy, metaphysics.
LEIBNIZ: Physics, Logic, Metaphysics
scientific work. On the other hand, this broad interest,
insofar as it remained oriented in architectonic
principles, led to a concentration on methodological
questions. In relation to the structure of a science,
these are more important than concrete results. The
position of Leibniz at the beginning of modern science
is analogous to that of Aristotle at the beginning of
ancient science. Leibniz' universality is comparable
with that of Aristotle, different only in that it did not,
as Aristotle's, remain grounded in essentially unchanged
metaphysical distinctions but evolved by
degrees from an encyclopedic multiplicity of interests.
Consequently, in the strict sense in which there is an
Aristotelian system, there is no Leibnizian system but
rather a marked metaphysical and methodological
concern that systematically expresses variations on
the same theme in the various special fields (such as
physics and logic) and underlies Leibniz' quest to
establish a unified system of knowledge.
Leibniz' autobiographical statement in a letter to
Rémond de Montmort in 1714 explains how, at the
age of fifteen, though accepting the mechanical
philosophy, his search for the ultimate grounds of
mechanism led him to metaphysics and the doctrine
of entelechies. This indicates the early orientation of
Leibniz' thought towards the ideas of the Monadologie.
Instead of setting out his philosophy systematically in
a magnum opus, Leibniz presented piecemeal clarifications
of his views in works that, in various ways,
were inspired by the publications of others. After
reading the papers of Huygens and Wren on collision
and the Elementorum philosophiae of Hobbes, Leibniz
composed his Hypothesis physica nova, consisting of
two parts, Theoria motus abstracti and Theoria motus
concreti, which in 1671 he presented respectively to
the Paris Academy of Sciences and the London Royal
Society. At this time, Leibniz owed more to Descartes,
whose work he knew only at second hand, than he was
later willing to admit. Closer study of the philosophy
of Descartes led Leibniz to a more decisive rejection.
In 1686 he published in the Acta eruditorum a
criticism of Descartes's measure of force, Brevis
demonstratio erroris memorabilis Cartesii et aliorum
circa legem naturae, which started a controversy with
Catalan, Malebranche, and Papin lasting until 1691.
Also in 1686 Leibniz sent to Arnauld, for his comments,
an essay entitled Discours de métaphysique, in
which he developed the ideas of the later Théodicée.
The tracts entitled De lineis opticis, Schediasma de
resistentia medii, and Tentamen de motuum coelestium
causis, published in the Acta eruditorum in 1689, were
hurriedly composed by Leibniz after he had read the
review of Newton's Principia in the same journal, in
an attempt to obtain some credit for results which he
had derived independently of Newton. In 1692, at the
instigation of Pelisson, Leibniz wrote an Essay de
dynamique, which was read to the Paris Academy
by Philippe de la Hire, and in 1695 there appeared in
the Acta eruditorum an article entitled Specimen
dynamicum, which contained the clearest exposition
of Leibniz' dynamics.
Leibniz' Nouveaux essais sur l'entendement humain,
completed in 1705 but not published during his
lifetime, presented a detailed criticism of Locke's
position. By adding nisi ipse intellectus to the famous
maxim, Nihil est in intellectu quod non prius fuerit in
sensu (wrongly attributed to Aristotle by Duns
Scotus1), Leibniz neatly reversed the application of the
principle by Locke. According to Leibniz, the mind
originally contains the principles of the various ideas
which the senses on occasion call forth.
In 1710 Leibniz published his Essais de Théodicée
sur la bonté de Dieu, la liberté de l'homme et l'origine
du mal, a work composed at the instigation of Sophia
Charlotte, with whom Leibniz had conversed concerning
the views of Bayle. In response to a request
from Prince Eugene for an abstract of the Théodicée,
Leibniz in 1714 wrote the Principes de la nature et de
la grâce fondées en raison and the Monadologie. When
in 1715 Leibniz wrote to Princess Caroline of Wales,
criticizing the philosophical and theological implications
of the work of Newton, she commissioned
Samuel Clarke to reply. The ensuing correspondence,
containing Leibniz' most penetrating criticism of
Newtonian philosophy, was published in 1717.
Rational Physics (Protophysics).
In his efforts to
clarify fundamental physical principles, Leibniz
followed a plan which he called a transition from
geometry to physics through a “science of motion
that unites matter with forms and theory with
practice.”2 He sought the metaphysical foundations
of mechanics in an axiomatic structure. The Theoria
motus abstracti3 offers a rational theory of motion
whose axiomatic foundation (fundamenta praede-monstrabilia)
was inspired by the indivisibles of
Cavalieri and the notion of conatus proposed by
Hobbes. Both the word conatus and the mechanical
idea were taken from Hobbes,4 while the mathematical
reasoning was derived from Cavalieri. After his
invention of the calculus, Leibniz was able to replace
Cavalieri's indivisibles by differentials and this enabled
him to apply his theory of conatus to the solution of
dynamical problems.
The concept of conatus provided for Leibniz a path
of escape from the paradox of Zeno. Motion is
continuous and therefore infinitely divisible, but if
motion is real, its beginning cannot be a mere nothing.5
Conatus is a tendency to motion, a mind-like quality