Archive for the 'Daily titbits' Category

FOLLOWING on from my post yesterday regarding people’s concept, or lack thereof, of evidence, it was suggested that it would be an interesting thought experiment for those of us who are willing to offer criticism on a subject to put ourselves on the receiving end. I think it’s a good idea to find something that each of us holds dear or true, and see if we can challenge ourselves to imagine how we’d feel if someone argued against that view. By understanding this, perhaps we can better approach our means of approaching such as subject with someone for whom such criticism would represent a paradigm shift.

As I managed to shake silly beliefs such as ghosts and ley-lines as a child, the only examples I have as a thinking adult are with particular scientific hypotheses that I’ve subscribed to, but subsequently had to ditch. This is the general method of science, and in my own research there have been any number of hypotheses I’ve formed and subsequently disproved on the basis of new evidence.

However, there have also been explanations for some natural phenomena that pre-date my research career, and to which I subscribed whole-heartedly. One example dates from my time as a first-year undergraduate studying marine biology. I had a particular interest in marine invertebrates and once attended a lecture by Donald Williamson, who was the major proponent of a larval evolution hypothesis, and recently came to light as being accused of ‘fringe science’ and getting a paper in the Proceedings of the National Academy of Sciences (PNAS) under the radar; thus also highlighting the pitfalls of the ‘I’ve got a mate in the club’ attitude to publishing.

Essentially Williamson felt that the immature forms (larvae) of many such invertebrates can be thought of as distinct organisms from the adult form, which are often comprehensively different both physically and physiologically; think caterpillar to butterfly, or blobby polyp jellyfish to its adult ‘medusa’ form.

Williamson felt that these different forms arose through hybridization — the fusing of two genomes (of two distinct organisms), one of which is now expressed early in an animal’s life, and the other late.

You can read an Sci. Am. article about it here.

I have to say, I absolutely LOVED this hypothesis, it was very exciting and I lapped it up with the typical fervour of an undergraduate.

Trouble is, since then it has been rebuked often and has not been substantiated by the experiments that were performed to test the hypothesis. I was quite recalcitrant about such rebukes up until the most recent PNAS rebuke that I’ve just linked to.

You can read rebukes to the Sci. Am. article here.

Changing my view about this hypothesis was hard, and a little embarrassing given I so animatedly communicated it to all my friends until I learnt it didn’t have strong grounding.

This is very true of many areas in which we are not experts, whether you are a scientist or not, and the fact is that we do tend to confer a great deal of trust in some individuals depending on their position. I would add that Donald Williamson was not ‘wrong’ to form this hypothesis at that time; scientific knowledge is by its very nature transitory, but once it has been tested, and alternatives developed, then we should seek to move on.

I could have easily ignored the evidence that Williamson’ hypothesis did not hold up to, and continued telling people an interesting and captivating story about why adult and juvenile forms of invertebrates are so different, but I didn’t. There’s still a part of me that thinks that there may still be something in it, which is why I can relate – to a point – with those people facing their first reality-check with regards some pseudoscience that they’ve hitherto believed in.

Donald Williamson is now retired and still stands by his hypothesis.

I don’t.