Alfred North Whitehead

Whitehead was born in Kent to an Anglican clergyman and schoolmaster, read mathematics at Trinity College, Cambridge, became a fellow in 1884 and taught mathematics there for twenty-six years. A Treatise on Universal Algebra (1898) brought his election to the Royal Society. Russell was his student; in 1900 they went together to Paris to meet Peano, and then wrote Principia Mathematica, published in three volumes in 1910–13. A fourth volume on geometry, his sole responsibility, was never finished.

In 1910 he left Cambridge for London, teaching first at University College and then Imperial College while administering for the University of London, and wrote the Principles of Natural Knowledge and The Concept of Nature, a philosophy of nature built from relativity on events rather than material points, along with his own theory of gravitation. He cared about education too: The Aims of Education attacks 'inert ideas' and proposes a rhythm of romance, precision and generalisation.

In 1924, at sixty-three, Harvard appointed him professor of philosophy, a subject he had never formally taught. The next thirteen years were his most creative. Science and the Modern World (1925) charged modern science with the 'fallacy of misplaced concreteness', mistaking abstractions for the concrete; his Gifford Lectures of 1927–8 became Process and Reality, a formidably difficult work that set out the 'philosophy of organism': the ultimate units of reality are 'actual entities', each an occasion of experience that prehends its past, synthesises, perishes, and is prehended by its successors.

In this system creativity is the ultimate category, and God is not an unmoved mover but a being with a primordial nature (the order of all possibilities) and a consequent nature (growing with the world and preserving all that happens), 'the great companion, the fellow-sufferer who understands'. Process theology and environmental philosophy grew from it. In his last years he received students on Sunday evenings at Harvard, and their notes of his talk became a book. Before he died he asked that all his manuscripts and letters be destroyed, and his family complied.