Γκότφριντ Λάιμπνιτς (Gottfried Wilhelm Leibniz) was a German philosopher, mathematician, and polymath born in 1646. He is best known for developing calculus independently of Ισαάκ Νεύτων (Isaac Newton) and for his contributions to logic and metaphysics. Leibniz introduced the notation used in calculus today, including the integral sign (∫) and the differential (d). In addition to his work in mathematics, Leibniz made significant contributions to philosophy, particularly with his ideas on monads, which are simple substances that make up the universe. He also emphasized the importance of reason and rationality, influencing later thinkers such as Εμμανουήλ Καντ (Immanuel Kant) and the field of φιλοσοφία (philosophy) as a whole.