Philosophers of logic

John Anderson (1 November 1893 – 6 July 1962) was a Scottish philosopher who occupied the post of Challis Professor of Philosophy at Sydney University from 1927 to 1958. He founded the empirical brand of philosophy known as Australian realism.
Anderson's promotion of 'freethought' in all subjects, including politics and morality, was controversial and brought him into constant conflict with the august senate of the university. However, he is credited with educating a generation of influential 'Andersonian' thinkers and activists—some of whom helped to place Sydney in the forefront of the 'sexual revolution' of the 1950s and 1960s.
To Anderson, an acceptable philosophy must have significant 'sweep' and be capable of challenging and moulding ideas in every aspect of intellect and society.

Paul Gerhard Natorp (24 January 1854 – 17 August 1924) was a German philosopher and educationalist, considered one of the co-founders of the Marburg school of neo-Kantianism. He was known as an authority on Plato.

Luitzen Egbertus Jan "Bertus" Brouwer (27 February 1881 – 2 December 1966) was a Dutch mathematician and philosopher who worked in topology, set theory, measure theory and complex analysis. He is seen as one of the founders of modern topology, in particular through his establishing the fixed-point theorem and the topological invariance of dimension.Brouwer also became a major figure in the philosophy of intuitionism, a constructivist school of mathematics which argues that math is a cognitive construct rather than a type of objective truth. This position led to the Brouwer–Hilbert controversy, in which Brouwer sparred with his formalist colleague David Hilbert. Brouwer's ideas were subsequently taken up by his student Arend Heyting and Hilbert's former student Hermann Weyl. In addition to his mathematical work, Brouwer also published the short philosophical tract Life, Art, and Mysticism (1905).