Jakob Thomasius (1622–1684) was a German academic philosopher and jurist. He is now regarded as an important founding figure in the scholarly study of the history of philosophy. His views were eclectic, and were taken up by his son Christian Thomasius.
He was influential in the contemporary realignment of philosophy as a discipline.
He wrote on a wide range of topics, including plagiarism and the education of women.
He was the teacher of Gottfried Leibniz at the University of Leipzig, where Thomasius was professor of Rhetoric and Moral Philosophy, remaining a friend and correspondent, and has been described as Leibniz’s mentor.
Otto Mencke (1644–1707) was a 17th-century German philosopher and scientist. He obtained his doctorate at the University of Leipzig in 1666 with a thesis entitled: Ex Theologia naturali — De Absoluta Dei Simplicitate, Micropolitiam, id est Rempublicam In Microcosmo Conspicuam.
He is notable as being the founder of the very first scientific journal in Germany, established 1682, entitled: Acta Eruditorum. He was a professor of moral philosophy at the University of Leipzig, but is more famous for his scientific genealogy that produced a fine lineage of mathematicians that includes notables such as Carl Friedrich Gauss and David Hilbert.
The Mathematics Genealogy Project database records as many as 69,247 (as of August 2012) mathematicians and other scientists in his lineage. The Philosophy Family Tree records 535 philosophers in his lineage as of May 2010.
Isaac Newton and Mencke were in correspondence in 1693.
Gottfried Wilhelm von Leibniz (July 1, 1646 – November 14, 1716) was a German mathematician and philosopher. He occupies a prominent place in the history of mathematics and the history of philosophy.
Leibniz developed the infinitesimal calculus independently of Isaac Newton, and Leibniz’s mathematical notation has been widely used ever since it was published. It was only in the 20th century that his Law of Continuity and Transcendental Law of Homogeneity found mathematical implementation (by means of non-standard analysis). He became one of the most prolific inventors in the field of mechanical calculators. While working on adding automatic multiplication and division to Pascal’s calculator, he was the first to describe a pinwheel calculator in 1685 and invented the Leibniz wheel, used in the arithmometer, the first mass-produced mechanical calculator. He also refined the binary number system, which is at the foundation of virtually all digital computers.
In philosophy, Leibniz is most noted for his optimism, e.g., his conclusion that our Universe is, in a restricted sense, the best possible one that God could have created. Leibniz, along with René Descartes and Baruch Spinoza, was one of the three great 17th century advocates of rationalism. The work of Leibniz anticipated modern logic and analytic philosophy, but his philosophy also looks back to the scholastic tradition, in which conclusions are produced by applying reason to first principles or prior definitions rather than to empirical evidence.
Leibniz made major contributions to physics and technology, and anticipated notions that surfaced much later in philosophy, probability theory, biology, medicine, geology, psychology, linguistics, and computer science. He wrote works on philosophy, politics, law, ethics, theology, history, and philology. Leibniz’s contributions to this vast array of subjects were scattered in various learned journals, in tens of thousands of letters, and in unpublished manuscripts. He wrote in several languages, but primarily in Latin, French, and German.