Rationalists and professional scientific thinkers have long since dismissed the principle of vitalism, which proposes that a force animates living things that cannot be explained by current physical law. Many historians trace the concept of vitalism to Aristotle, but I would suggest that the instinct to give a vital force and conscious motives to entities like harvest crops, prominent geographical features and the weather is as old as religion, which is to say as hold as the human race (if not older).
Aristotle proposed that a non-reducible ‘spirit’ separates the inanimate from animate life. More recently, through two world wars the developmental biologist Hans Driesch found that you could isolate a single cell from the first few divisions of a fertilized sea urchin egg and the cell would still make a functional embryo, though a smaller one. Driesch decided that he had evidence that life develops certain profound rules that are distinct from its immediate physical environment. The embryos followed a vitalistic impulse if you will.
Having continued Driesch’s line of inquiry for the better part of a century, we now know that his embryonic urchin follows the guidance of pathways with various exotic and not-so-exotic titles: hedgehog, notch, wnt and MAP kinase collaborate, compete and feed back on one another to tell each cell whether, how and where to divide.
It took a long time but at last we delineated the embryo’s pathways. We scaled the peak, we named it, we planted a flag and some of the more significant people won a Nobel for it. That means we have conquered the superstitious vitalistic impulse and replaced it with something rational. Right?
Don’t count on it. More than that, it might not be a bad thing. Let me put it this way: the other day I got my reviews back for a paper that I submitted to one of the top three or four journals in the world. My lab and five or six others have already reported results consistent with this paper, but the two reviewers refused to believe that any such thing is possible. It violates what we already know are universal rules about how (this bit of) life works!
In the world where rationalistic explanations have won for good, they would be right. Impossible ideas that contradict known rules must be crazy and wrong. However. Ask a leading expert in any field and you will hear the same thing: we only barely understand how much we do not know. Every aspect of life is still ruled by invisible, inchoate forces. The ones we understand have underlying causes that we do not even know we do not understand yet. In fact, to put a finer point on it, just about every leading expert made his or her name by proving that the fixed rules that previously governed the rational world were either wrong or incomplete.
In a sense, then, I think that vitalism is not dead or even quiet. It sits on the shoulder of people like me who try to make sense of the world. Once in a while, often in the form of results that don’t make any sense but stubbornly refuse to change when we repeat them, it gives a gentle prod that we don’t understand everything and to some degree we never will. The noumenous might not be tangible but it is real.
Let me put it a different way: It is hardly controversial to say that inchoate or semi-choate forces animate life, the universe and everything. It just means that, as GLaDOS put it, there’s still science to do. The noumenous forces that Driesch proposed have names now, yes, but each of those has its own poorly (or mis-) understood animating force. Judging by history (and the pages of any given high-impact journal) even a good bit of the territory we already mapped is either incomplete or wrong. In that sense we need vitalism precisely because it is illogical; it is an intellectual memento mori that gently prods us to keep a grain of humility in the midst of triumph*.
Hard religion, hard anti-religion and inflexible rationalism therefore all make the same mistake. It makes no more sense to say out of the blue that you know every answer to the ineffable than to say that you know that the answers are wrong (which is just another way of saying that you know the answers). You need to give each possible model a fair weight and build a watertight argument that convincingly rules out every other explanation, all while understanding that despite your best efforts you could still be wrong. That, in a nutshell, is science.
(*) I do not say that lightly; my last three papers came out in either a Nature journal or PNAS. It really is not that big a deal if I have to shop around the current one a bit more. And who knows, it might be wrong.