Wednesday, October 1, 2014

Nature or nurture? Tristram Shandy weighs in!

It is only because of our very casual and cursory attention to history that we credit Charles Darwin, in 1858, with showing us that every aspect of our natures is due, entirely and with infinite determinism, to natural selection fine-tuning our genomes.  We like heroes and because we're scientists, we want the heroes to be other scientists (so we can liken ourselves, and our own inherent brilliance, to those heroes).  We dismiss philosophers and historians of science as meddlers in our business if they do not cling to the mythologies we prefer about ourselves (and our inherent brilliance).  But if we're really scientists, and truly truth-seekers, we must bow to discoveries that undermine our self-flattering tales.  It hurts, it really hurts, if the discovery shows that the pioneers of our field were, in fact, religious or, worse, totally un-versed in the lore of science and the pursuit of objective fact.

But such is the sad reality about the fact of complete genetic determinism.

The opinions and discoveries of Laurence Sterne (as expressed by Tristram Shandy)
In 1761-3, the Rev. Laurence Sterne, published his study of environmental determinism, called The Life and Opinions of Tristram Shandy, Gentleman.

Laurence Sterne (1713-68); image from Google images
The book is written as a narrative of his life, by the title character.  Tristram notes that at the very moment of the act that led to his conception Mrs Shandy blurted out "Pray my Dear, have you not forgot to wind up the clock?"  About that question her husband, though a man of exceedingly regular habits, replied "Good G..!  Did ever woman, since the creation of the world, interrupt a man with such a silly question?"  The clock in question is shown in the background of this figure; in the foreground is a depiction of the use of forceps in deliveries (which crushed Tristram's nose during his birth).

The Shandy home (and the clock), from 1761 edition.  By Wm Hogarth, from Wikipedia images

Here is how Tristram describes the lifelong impact of his mother's ill-timed distraction:
I wish either my father or my mother, or indeed both of them, as they were in duty both equally bound to it, had minded what they were about when they begot me; had they duly consider'd how much depended upon what they were then doing;--that not only the production of a rational Being was concerned in it, but that possibly the happy formation and temperature of his body, perhaps his genius and the very cast of his mind;--and, for aught they knew to the contrary, even the fortunes of his whole house might take their turn from the humours and dispositions which were then uppermost;--Had they duly weighed and considered all this, and proceeded accordingly,--I am verily persuaded I should have made a quite different figure in the world, from that in which the reader is likely to see me.--Believe me, good folks, this is not so inconsiderable a thing as many of you may think it;--you have all, I dare say, heard of the animal spirits, as how they are transfused from father to son, & &--and a great deal to that purpose:--Well, you may take my word, that nine parts in ten of a man's sense or his nonsense, his successes and miscarriages in this world depend upon their motions and activity, and the different tracks and trains you put them into, so that when they are once set a-going, whether right or wrong, 'tis not a half-penny matter,--away they go cluttering like hey-go mad; and by treading the same steps over and over again, they presently make a road of it, as plain and as smooth as a garden-walk, which, when they are once used to, the Devil himself sometimes shall not be able to drive them off it.

. . . . .

--Then, let me tell you, Sir, it was a very unseasonable question at least,--because it scattered and dispersed the animal spirits, whose business it was to have escorted and gone hand in hand with the Homunculus, and conducted him safe to the place destined for his reception. . . . . Now, dear Sir, what if any accident had befallen him in his way alone!--or that through terror of it, natural to so young a traveller, my little Gentleman had got to his journey's end miserably spent;--his muscular strength and virility worn down to a thread;--his own animal spirits ruffled beyond description,--and that in this sad disorder'd state of nerves, he had lain down a prey to sudden starts, or a series of melancholy dreams and fancies, for nine long, long months together.--I tremble to think what a foundation had been laid for a thousand weaknesses both of body and mind, which no skill of the physician or the philosopher could ever afterwards have set thoroughly to rights.

. . . . .

That I should neither think nor act like any other man's child:--But alas! continued he, shaking his head a second time, and wiping away a tear which was trickling down his cheeks, My Tristram's misfortunes began nine months before ever he came into the world.
The surprise is that more than two centuries ago at least some views were directly contrary to the predominant view these days, reflecting the way so much of our research resources are currently committed--that is, to the idea that genes rather than experience are what (also from the moment of conception) make us what we are.  But not everyone shared this view!

Things were debated even back then!
Last week we noted that in 1862, just after Darwin's Origin of Species, the novelist Wilkie Collins expressed the debate between Nurture advocates and their Nature foes as to which was responsible for our behavior. This was exactly a century after Sterne's Nature view just described.  Sterne had no notion of 'genes' and Tristram didn't attribute his nature to inheritance, which would put him in the Nurture category, even if at the extreme (being parentally distracted in flagrante delicto defined the imminent conceptus's entire future).

It wasn't long thereafter that the power of inheritance was debated, in little-remembered works, that applied to the same behavioral characteristics discussed in fiction.  Almost half-way between Sterne and Collins, in 1808, one M. Portal, a French professor of medicine, published the "Considerations on the Nature and Treatment of some hereditary or Family Diseases" (London Med. Phy. Journal, 21, 229–239, 281–296).  Members of the upper classes (at least) were concerned that they might sully their noble posterity by transmitting disease, especially mental disease, from parent to offspring.  Many traits were known to be transmitted (as Montaigne is quoted by Portal), "We find that not only are the marks of the body transmitted from father to son, but also a resemblance of temper, complexion, and inclinations of the mind."

A few years later, in 1814, a British physician named Joseph Adams took Portal's work to task, arguing that there were other ways that traits could cluster in families.  He, too, was speculating in that he hadn't the kinds of precision or systematic analytic methods we have today.  But he carefully pointed out that life-experience, infection, and other causes could account for such clustering.  Diseases present at birth, for example, were more likely to be hereditary than diseases that, even if similar among relatives, only appeared later.  He noted that inherited predisposition could lead to a disorder only after experiencing some environmental or life-style factor.  He was particularly interested to calm down those in the upper classes who were worried that behavioral traits ('madness') were inherited.  Additionally, Adams explicitly anticipated much of Darwin's ideas about evolution by natural selection, but that's unrelated to our topic today.  We've discussed Adams' book on MT before.

Joseph Adams' book, 1814

The bottom line is that, from these instances, ones that I just happened to know about, both literature and science reflect the fact that in the post-Enlightenment era we often think of as the Age of Science, western culture has long known of what appeared to be inherited traits, even if 'genes' per se weren't yet known of, and yet it was also clear that experience and living conditions could not only generate traits but generate family resemblance of traits.

But nobody knew the how, when, or why of the two kinds of cause, and without knowing units of causation in either life-experience or genetics, we had simply to guess or speculate about these things. The 20th century gave us Mendelian patterns to look for in families as signatures of genetic causation, but when we realized early on that many genes could generate similar traits it was known (to those who cared to recognize that fact) that Mendelian patterns were not needed even in 'genetic' traits.

We have almost the same level of confusion, mix, debate, and lack of clarity today, centuries later in our amped-up Age of Technical Science.  We now throw around terms like 'interaction' without, usually, having much direct sense of what we are actually referring to.  Sometimes, the contorted way we describe our ideas of causation seem not much different from the way Tristram Shandy did--only that was satire and we seem to be deadly serious!

Something's missing.

After-note:  If you haven't read Tristram Shandy, and are interested in more than just reading the flood of science articles in the journals that jam up your mail box every day, Sterne's book is a good, if wacky, romp through sense and nonsense.  Reading it takes patience, since it intentionally doesn't always flow in one direction, but it's no more contorted and obscure than those same science articles.

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