Peter Thomas Geach[a] FBA (29 March 1916 – 21 December 2013) was a British philosopher who was Professor of Logic at the University of Leeds.

[3] His father, who was employed in the Indian Educational Service, would go on to work as a professor of philosophy in Lahore and later as the principal of a teacher-training college in Peshawar.

One day my defences quite suddenly collapsed: I knew that if I were to remain an honest man I must seek instruction in the Catholic Religion.

[12]Geach spent a year (1938–39)[9] as a Gladstone Research Student, based at St Deiniol's Library, Hawarden.

In 1951, Geach was appointed to his first substantive academic post, as assistant lecturer at the University of Birmingham, going on to become Reader in Logic.

[18] At various times Geach held visiting professorships at the universities of Cornell, Chicago, Michigan, Pennsylvania, and Warsaw.

"[20] Geach dismissed both pragmatic and epistemic conceptions of truth, commending a version of the correspondence theory proposed by Thomas Aquinas.

He is said to have invented the famous ethical example of the stuck potholer,[4] when arguing against the idea that it might be right to kill a child to save their mother.

Geach made a notable contribution to this debate with a paper published in 1977, which purported to derive one categorical 'ought' from purely factual premises.

[28] Peter Geach died on 21 December 2013[29] at Addenbrooke's Hospital in Cambridge and is buried in the same grave as his wife in (what is now) the Ascension Parish Burial Ground.