Would you say that astrology is very scientific, sort of scientific, or not at all scientific? The question was asked in a survey in the United States, and according to Science and Engineering Indicators 2014 'slightly more than half of Americans said that astrology was "not at all scientific"'. The rest, almost 50 per cent, were willing to grant it credibility, a higher proportion than in previous surveys. Perhaps that indicates a decline in rational scepticism, but an alternative interpretation suggests itself: many respondents had simply confused astrology and astronomy. It's a common enough mistake: when the Daily Mail profiled the ailing Patrick Moore not long before his death in 2012, they dubbed him an 'astrological legend'. One can only hope the error did nothing to hasten the great man's demise.

As an amateur astronomer myself, I'm used to the mix-up, though to be honest, the confusion doesn't particularly trouble me. Don't get me wrong, I am not going to suggest there is any plausibility in the idea that the gravitational field of Jupiter can stimulate life-changing tidal forces in my head. But while the boundary between science and pseudo-science seems clear enough in theory, it's not always so straightforward in practice. The reason, in many cases, is that both draw on the same recurring set of ideas.

I would like to propose what I shall call the principle of eternal folly. It states that in nearly every era there arises, in some form, nearly every idea of which humans are capable. Certainly, there is the emergence of new ideas: technological ones are the most obvious, but there are others, too. I do think it fair to say that Jane Austen, Beethoven, and even the occasional entrepreneur have invented radically new things. However, the vast majority of ideas are recycled - and it is when we fail to recognise this, as we eternally do, that we commit folly. ...[Continue reading on Aeon]