pleasure in the predicaments which came before me as a
muster-roll of all the things in the world, and I turned to
"Logics" of all sorts to find the best and most detailed
form of this list.' In later years, the possibility, of a 'mus-
ter-roll of things' developed into the possibility of a logi-
cal calculus, and an 'alphabet of concepts' as a means to
the discovery of truth.

When he was fifteen years old, Leibniz entered the
University of Leipzig. His favourite teacher was Jacob
Thomasius, who was chiefly interested in ancient and
scholastic philosophy. At the same time, Leibniz was read-
ing privately the more modern philosophical writings and
all the important mathematical treatises. Among these
were Bacon De Dignitate et Augmentis Scientiarum, and
the works of Cardan, Campanella, Kepler, Galileo, and
Descartes. This reading made him at first a mechanist in
philosophy and a mathematician. In 1663, he graduated
from the University with a thesis entitled Disputatio Meta-
physica de Principio Individui, in which many of his later
metaphysical views were foreshadowed. His intention at
this time was to enter the profession of Law, and he
accordingly went to Jena, where the mathematician
Erhard Weigel was lecturing on the Laws of Nature, or
what we should now call Jurisprudence. In 1666, the Uni-
versity of Leipzig refused him his Doctorate in Law on
the grounds of his youth, but his thesis De Casibus per-
plexis in Jure was accepted by the University of Altdorf,
which also offered him a professorship: this, however,
Leibniz declined.

Leibniz next spent a year in Nürnberg, at that time the
capital of a small republic. Here he became a member of
the Rosicrucians and made friends with a fellow-member,
Baron von Boineburg, one of the most celebrated diplo-
mats of his age. Boineburg had formerly been minister to
the Elector and Archbishop of Mainz, the most powerful

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