What Leonardo missed: a lesson for today

Abstract

Alice : There’s no use in trying. One can’t believe in impossible things. The Queen : I dare say you haven’t had much practice. When I was your age I always did it for half an hour a day. Why, sometimes I believed in as many as six impossible things before breakfast. Lewis Carroll was not the only philosopher who has observed, if in this case obliquely, that scepticism of received wisdom is important to the advancement of knowledge. Indeed, it could be argued that significant advance in understanding rarely occurs without an obstinate refusal to accept what one has been taught. Such behaviour is hazardous, as Galileo discovered when he proposed that the Earth was not the centre of the universe. Today it may lead, at least, to difficulty in getting grants and publishing. Most of us start out in life believing what we are told, be it fairies, Father Christmas, or God. Soon enough we learn scepticism, discarding at least two of these and perhaps rationalizing the third. But after a decade or two of education filling our heads with facts some of us begin to lose our habit of questioning; it takes a bold student to challenge authority. Later, we start to realize that much we were taught is incomplete or wrong. Only the most adventurous will start to test this for themselves; it is easier and safer to swim with the current. Some years ago, while I was preparing a lecture in commemoration of William Harvey, …