Why do scientists keep changing their minds?

I highly recommend an article in the current (October 23^rd, 2014) issue of the New York Review of Books entitled “What Scientists Really Do” by Priyamvada Natarajan. Science is a communal effort to continually and systematically acquire more knowledge about the world and the universe we find ourselves in. What some people find difficult to understand about this process, or, as Natarajan points out, others quickly use as an excuse to calm their religious doubts or to continue making money to the disadvantage of society, is that scientific knowledge is provisional. We know a lot more about things now than we did a hundred years ago, but there’s still a lot more we don’t know and which our grandchildren will wonder how we missed. I find it a glorious, ongoing story of wonderment.

Therefore, at any point in a particular knowledge development, the current knowledge is considered provisional, recognizing humbly that others will take it further. And that’s why we scientists tend to use the word ‘theory’ to describe a particular current system of understanding. But then sadly, non-scientists, either through a lack of understanding of this process, or through deliberate malfeasance, then say: ‘Well, if it’s just a theory, you have no absolute proof, then I don’t have to believe it.’

Perhaps we scientists make trouble for ourselves by being a bit too honest, too precise. ‘Provisional’ implies that the understanding of a particular system could be reversed. Yes, possible, but very rare. Isaac Newton gave us his theory of gravity. It was a theory, but anyone who hasn’t taken that very mysterious force seriously has learned the hard way, even before Einstein showed that Newton hadn’t gotten it quite right and brought in some refinements. Nowadays Einstein is held up as the quintessential genius. But it wasn’t always like that. When he first proposed his theory of relativity there were many doubters. The term ‘relativity’ didn’t play well with those concerned with the loosening of moral behavior in the ‘roaring twenties’, and one Columbia University professor said it sounded like Bolshevism. Nevertheless, whatever our political or religious views many Americans today take for granted the use of their cellphones and the GPS guidance systems in their cars that only work if Einstein’s theories are correct, or shall we say more refined than Newton’s. Will there be further refinements in our understanding in this realm? Probably. In recent years a few brave physicists have been working to try and use gravity to transmit information. Silly? Probably, but remember that our present understanding remains provisional. And, in seeking to harness gravity in this way they may fail in that, but meanwhile discover something else. Arthur Koestler entitled his book on the history of man’s quest to understand the cosmos “The Sleepwalkers”, describing the zig-zag lurching of man’s understanding of the puzzle. 

Science proceeds for a variety of interconnecting reasons.  Ambition – the striving of younger scientists to make their name and prove the old codgers wrong.  The interchange of new technology, so that computers have revolutionized the ability to analyze across every scientific discipline. Advances in genetics, in particular DNA analysis, have led to major advances in recent decades from medicine to paleoanthropology to botany. 

Ever since Linneaus in the 18^th century botanists thought that aster flowers in Eurasia and North America were in the same genus – Aster. Then in 1994 it was discovered that Eurasian asters had larger, more symmetrical chromosomes. This was bad news for American botanists as they had to come up with a new name for the approximately 180 aster species in North America. Taking the opportunity, or precaution, for more detailed study of these delightful flowers a team of American botanists not only chose the difficult-to-spell new generic name of Symphyotrichum as the main generic name replacing Aster, but broke other species off into several other smaller genera including Sericocarpus, Eurybia and Oclemena. Most species kept their old specific names. However, Symphyotrichum has the neuter gender in Latin whereas Aster is masculine, so that the ending of the specific name also had to be changed in many cases. So that Aster puniceus became Symphyotrichum puniceum. This led one frustrated botanist in Missouri to write a paper entitled “How faster to master the Aster disaster”. 

What I’m trying to show here is that advances in science (whether in physics, astronomy or botany) can be messy, run into opposition, and make the subject more complicated, but in the end do lead steadily towards greater refinement and more detailed understanding of the subject, bringing that provisionality up the asymptotic curve of knowledge, while also giving an advantage to the younger, fresher minds, which is at it should be.