Darwin Didn’t Always get it Right

My Christmas reading included two very different books, one by Tim Birkhead and one edited by Bill Bryson, both gloriously illustrated with historical paintings. Reading these in quick succession over a short period of time caused me to reflect on the different historical time-spans of physical and biological sciences qua sciences and the different ways they developed.

Having been a youthful twitcher, I thoroughly enjoyed reading The Wisdom of Birds by Sheffield Zoology professor and FRS Tim Birkhead . When at the height of my ornithological enthusiasm I was still developing a sense of my own interest in science, but I was nevertheless totally committed to physics rather than biology. At the time I don’t think I had any appreciation of what a recent science ornithology was, something The Wisdom of Birds made very clear. As a child/teenager I was familiar with many of the amazing new nature programmes then on TV (even if in my case only in black and white), showcasing amongst other things the sterling work Peter Scott did at Slimbridge. One example of that would have been the work with nenes (Hawaian Goose) which he, fairly single-handedly, brought back from the verge of extinction to a current wild population of around 1000 birds. But whether that work was based on fundamental scientific knowledge or simply experience, I am not entirely sure.

Reading Birkhead’s book demonstrated just how little birds were understood, scientifically, really until well into the 20^th century. For instance there is the well known myth which survived at least until the18th century that swallows hibernated in the mud at the bottom of ponds. This was believed  by, amongst others, the great Linnaeus, he of the Linnean system of nomenclature.  Many other aspects of behaviour seem to have been appreciated by bird-fanciers, farmers and breeders, who were necessarily observant because their livilihood depended on it,  but not by ‘scientists’ (though of course that term did not  exist yet) who went off up blind alleys as a result. An example of this discussed in detail by Birkhead concerns infidelity in birds.

As far back as Aristotle it had been noted that females might copulate with more than one male; the Moors in the Middle Ages used ‘thief pigeons’ to lure other pigeons back to their dovecotes, so that a truly attractive male could induce a female to leave her nest and her partner and accompany him wherever he would. Nevertheless Darwin himself posited quite explicitly male promiscuity as the norm, not female, and this idea formed a key part of the development of his ideas of sexual selection.  He did this despite the existing evidence, despite his cousin the Reverend William Fox (a typical amateur naturalist) spelling out to him in a letter the idea of female promiscuity (in this case in domestic geese).  Birkhead suggests that despite all the indications, one explanation for why Darwin did not ‘see’ female infidelity was because it was not something Victorian gentleman discussed, and by ignoring it, it saved embarrassment at home. I don’t find this entirely convincing because Darwin’s worries about how God fitted into evolution undoubtedly caused embarrassment with his wife Emma at home, but it didn’t stop him pursuing his theories in that direction.

Buffon in France somewhat earlier (1770) likewise espoused female fidelity, explicitly in the pigeon which, as I mention above, was well known to be a bird with dubious female morals.

A flame always constant, and ardour continually durable;….no caprice, no disgust, no quarrel to disturb the domestic harmony, their whole time devoted to love and progeny; the laborious duties mutually shared; the male assisting his mate in hatching and guarding the you: – If man would copy, what models for imitation.

(I like this quote, for fairly obvious reasons concerning the desirability of humans imitating the male pigeons’ exemplary domestic behaviour.) These ideas were so prevalent, and Darwin himself had such influence, that no one challenged the idea of female fidelity until the 1950’s when David Lack started questioning the orthodoxy. Slowly it became apparent that natural selection at the level of the species, which is what female fidelity implies by maintaining ‘harmony’, was wrong. What mattered was natural selection at the level of the individual – which indeed was part of Darwin’s original vision which had somehow got lost in a cosier view of male-female relationships contributing to the good of the whole population. If a female shares her favours it means the best sperm wins, so that there is a sperm competition and optimisation of which genes pass into the next generation.  This insight transformed the field. But, if the observations of lay people had been recognized earlier, it could have happened at least 100 years before. (In parenthesis it should also be noted that, as Darwin mulled over his ideas which became On the Origin of the Species, he corresponded with many breeders  -of pigeons and many other kinds of animals – and experimented himself in this direction.  He knew that these people had much to offer, but failed in this particular instance to avail himself of their knowledge.)

There are many other examples in Birkhead’s eminently readable book of how non-professionals acquired much detailed knowledge  about, for instance, birdsong, territory, plumage and the existence of hermaphrodites, while the professionals struggled. This state of affairs is very different from that described in Seeing Further, the collection of essays edited by Bill Bryson and produced as part of the Royal Society’s 350^th Anniversary in 2010. The chapters regarding the early years of what was then known as the ‘College for the Promoting of Physico-Mathematical Experimental Learning’, deal almost entirely with the physical sciences because that was the original focus, as implied by the early society’s title. The first Fellows – chaps like Newton, Boyle, Pepys and Hooke to list a few of their illustrious names – were concerned with celestial motion and mechanics more generally, optics and ‘airs’, all topics from the physical sciences. Only occasionally at this time did living matter enter into their studies, although interestingly in the 1660’s Birkhead points out that the Royal Society commissioned one of its members, the Polish astronomer Johannes Hevelius to establish ‘What truth there is…concerning swallows being found in winter under waters congealed and reviving, if they be fished [out] and held to the fire.’  Intriguing that an astronomer was chosen for this task, but presumably reflecting the preponderance of such amongst the early fellowship.

The middle of the 17^th century, when the Royal Society was being set up, was the time science moved from observation and abstract thought to direct experimental observation and hypothesis testing.  Experiments were devised explicitly to check ideas out, ideally with mathematical equations in there: no longer was it adequate simply to ‘observe’ in a phenomenological way.  Not everyone accepted this shift yet, and the arguments between Boyle, with his air-pump, and Hobbes worked through in Shapin and Schaffer’s classic book Leviathan and the Air Pump, illustrate this. Crudely speaking, Hobbes would not concede that experimentation was better than argument, and the debate, heated at times, went on between the pair over an extended time.

This move to experimentation was reflected in the Royal Society’s motto Nullius in Verba, usually translated as ‘take nobody’s word for it’.  But it didn’t of course stop people denying the ‘truth’ of experiments. One of the interesting aspects of these early days is the value accorded to ‘witnesses’, the more the merrier. Thomas Sprat, in his History of the Royal Society (1667) says

Whether, seeing  all Countreys, that are govern’d by Laws, they expect no more, than the consent of two, or three witnesses, in matters of life, and estate; they will not think, they are fairly dealt with withal, in what concerns their Knowledg, if they have the concurring Testimonies of threescore or an hundred. 

However, these witnesses had to be the ‘right sort of people’. In the chapter in Bryson’s book by Schaffer he points out, for instance, that gentleman were to be trusted more than their servants. In attempting to gather evidence about a lightning strike on a Norwich workhouse, Fellows were sent out to try to find out what really happened – they cared because they were bothered about how effective lightning conductors were. Spectacular fireballs were reported, including by ‘one of the cripples in the House of Industry, a middle-aged woman’ but they weren’t sure ‘if any credit could be given to the testimony of such a person in a matter like this’. (Was it her status as a woman, a cripple or middle-aged that damned her, or simply because she was an inmate in the workhouse?).

So in the physical sciences, around the middle of the 17^th century, it is clear that gentleman and aristocrats were carrying out science in a way that would still be recognizable today, albeit with very different degrees of sophistication of apparatus. But at that point, biology did not exist as we would recognize it. Livestock breeders, bird-fanciers etc might know a lot of lore, and have experience of many aspects that now underpin genetics and behavioural science, for instance, and which subsequently were found to be very useful. But there was no framework in which to work on what now would be termed biology, and wouldn’t be for a long time to come.

Rutherford said something along the lines of

All science is either physics or stamp collecting (different sources quote this in slightly different words)

and I think that reflects this difference between biology – before it emerged properly from  fairly phenemonological natural history study which might be equated crudely with stamp collecting – and the physical sciences, which were kick-started by observing the heavens coupled with the need to develop optical instruments to do this better.