Arthur Atkinson, as he was known to us, was born in Harrow, and educated at University College London. An English master at his school awakened his interest in observing nature, and Arthur developed into an unusually well-informed naturalist, with a special interest in butterflies and the plants which support them. During his long career in teaching, Arthur passed on this knowledge and enthusiasm to many of his own pupils. He was also a naturalist in a philosophical sense: ultimate reality for Arthur was nature. What he saw going on within himself and the world around us were natural processes: it was only through the study of those processes that we were able to understand how the world works. But there was no explanation of life itself: Arthur often said that “life is a mystery”, and “our existence is inexplicable.” He thus rejected religious explanations, having moved away as a young man from the Methodism of his home background, and eventually joined not only SPES but also the other three main humanist organisations.

Arthur was firmly opposed to mind/body dualism: we live in one world, not two. So much so that he tried to avoid the word “mind” as much as possible, if not entirely, by using the word “brain” instead. You can read more about that in his book The cosmic fairy (1996). He called it “disposing of the mind”: Arthur was a one-man mind-disposal unit. As for his own brain, Arthur retained his faculties well into his nineties, and one reason for this, I imagine, was his long-standing active membership of Hayes Chess Club.

In his patient observation of nature, Arthur had much in common with Charles Darwin, whose theory of evolution offered a more convincing explanation of how species came about than by divine creation, and whose achievement Arthur called the “Darwinian Enlightenment,” although it was left to others, amongst whom we can include Arthur, to draw out fully the implications of the theory for religion. Darwin lived the latter part of his life in the age of Victorian Doubt, which gave rise to the poetry of Hardy, Housman, Tennyson and others which Arthur found so moving.

A striking aspect of Arthur’s personality was what the Romans called gravitas. This came to him quite naturally: it was not a pose or an affectation, and it is a good quality in a teacher seeking to engage the interest of schoolchildren. Arthur was a serious person: he looked you in the eye when making a serious point, and he expected you to engage with him at the same level. But if there was sternness, there was also kindness: he was a founder member, and for many years the Secretary, of Ealing Humanist Association, and had the kind of pastoral care for its members which few of us could match, checking on their progress when they were ill, and staying in touch with members long after they had become too infirm to come to meetings. He was also unfailingly polite, a quality perhaps going back to his earliest years in a now vanished age. This enabled him to inspire both respect and affection, even in those who disagreed with him, and also in his former pupils, now long since grown up.

Arthur died in Ealing Hospital on 14 May: the funeral on 29 May, which was conducted by Leslie Scrase, included an "obituary" written long ago by Arthur himself. At the subsequent reception, a fitting farewell to Arthur was rounded off by a slide-show of butterflies given by Clive Farrell, with whom Arthur collaborated in establishing the Butterfly House at Syon Park.

Charles Rudd