So today I’m in Golden, CO, of all places, waiting to give a seminar on “Synthetic Biology and Origins” (or maybe the other way around). This always brings up the odd place I occupy in the scientific spectrum on origins. I’ve pretty much been an origins of life biochemist most of my career, from my graduate work with Steve Benner to my development of in vitro selection with Jack Szostak to my own independent career, which has always to my mind been trying to invent life for fun and profit. So, I think I am somewhat qualified to speak on the subject. But what I have to say usually sets most folks’ teeth on edge, one way or the other.
To wit: there is no such thing as origins of life, because there is no such thing as life. Life is not a meaningful scientific term. It is a term for poets, not scientists. I think this began to become evident to me as I watched my peers unsuccessfully try to define this term, over and over. Now, this could mean that there is a very deep problem here, a problem whose solution has somehow eluded philosophers and scientists for thousands of years. Or it could just mean that it’s a stupid question. I have finally come around to the latter position.
Another way to examine this position is to observe how chemistry is taught relative to biology. While I am comfortable with the notion that electrons and atoms are at some level abstractions and fictions, they are at least well-defined abstractions and fictions, and can be manipulated within predictable frameworks. In the first few pages of a biology text, though, you never come across the definition of life. You may get an empirical description of living systems, but the underlying definition is never manifest. Instead, the framework for the study of biology is evolution, as it should be. But, interestingly, nothing about evolution implies the existence of a living system.
These views are unpopular both with normal folks, who of course find the notion that nothing is ‘alive’ to be counterintuitive at best and blasphemous at worst, and with scientists, who are queasy with them because they intuit the truth of the matter, and don’t like having to take a position that the lay public would adjudge offensive.
Invariably when I bring these issues up I am challenged with an existence proof: there, what’s that, then? That bug crawling, that plant growing? Life is apparently like pornography: you may not be able to define it, but you know it when you see it. And my reasonably well thought-out reply is: you are talking about replicators, and these replicators take different forms and have different degrees of complexity. From this vantage, the age-old saw about whether a virus is ‘alive’ melts away: viruses are replicators, they use cells as their environment, just as we are replicators that live off of an environment that includes air. Viruses cannot replicate without someone else giving them a ribosome; we cannot replicate without air. And, yes, I’m perfectly happy with crystals replicating in their little niche, and computer programs in theirs. It is the description of the replicator that is important, not any supernatural patter attached to a given class of replicator.
- originally posted on Thursday, July 1st, 2010