My friend and colleague Colin Howson, who has died aged 74, was an internationally renowned philosopher, logician and expert in probability with a long list of academic papers and influential books to his name.
Colin died from an irremediable brain tumour. In his book Objecting to God, he argued passionately and with logical precision against those who, on religious and other grounds, oppose “the principle of self-determination” – the right under certain circumstances to determine one’s own end. This he was able to do as a resident of Canada, where physician-administered euthanasia is legal.
He was born in Mill Hill, north-west London, to Harry, a civil servant, and Daisy (nee Maynard), a housewife. The family moved to Devon, where he attended Colyton grammar school, becoming head boy. In 1963 he enrolled at the London School of Economics, initially to study economics, but soon transferred to philosophy. Then, in 1968, shortly after beginning his doctoral studies, he accepted a lectureship in the LSE’s department of philosophy, logic and scientific method.
Though a student and a teacher in a department dominated by the philosophy of its founder, Karl Popper, Colin remained his own man and developed a course diametrically opposed to Popperianism. His work focused on the assignment of probabilities to scientific theories via a central theorem of probability proved in the 18th century by Thomas Bayes. Bayesian inductive reasoning, which before the 20th century was fairly standard, had not just dropped out of fashion but had fallen into obloquy.
He contributed to a remarkable revival of Bayesianism through his exposition of the axioms of probability as laws of consistency and rational discourse, comparable to the laws of deductive logic. His book Scientific Reasoning: The Bayesian Approach, which I co-authored, went through three editions between 1989 and 2005, and is considered the canonical philosophical defence of Bayesian reasoning.
Appointed professor of logic at LSE in 1997, Colin was president of the British Society for the Philosophy of Science from 2003 to 2005. He met the Canadian philosopher Margaret Morrison at an LSE conference and they married in 2003. On retiring from the LSE in 2008, he accepted a position in the department of philosophy at the University of Toronto.
Colin was known for his immense charm, razor-sharp mind, exceptional intelligence, open-mindedness and ever-inventive wit. His many successful doctoral students remember him as an encouraging mentor. And he was a good friend to numerous colleagues and collaborators.
Margaret survives him.