Do Pathogens Time Travel?
Evolution arises out of grave failure. Natural selection requires large and variable populations comprised for the most part of organisms whose designs fail to match their present circumstances. Any design matched right is in the meantime still subject to chance destruction occurring across spatiotemporal scales.
So strict engineering optimization is embodied in no organismal design, contra religiosos and radical adaptationists alike. Nor does it reside in the process of selection: every species eventually dies out–by maladaptation, stochastic extirpation, or an external force (say, a large meteorite in yo’ face).
And yet biological life began early on Earth and continues on four billion years later, and will do so in one form or another after the present climate collapses or we nuke ourselves senseless.
By this persistence, then, organismal life can be conceptualized as a locally bounded and frameshifting Turing process, after Alan Turing’s notion of a machine that can simulate the logic of any computer algorithm. Organisms’ contingently recursive ontogenies aim to solve just about any and all problems they face during their lifetimes, until the next generation is birthed and reaches reproductive maturity. Just enough push until the baton is passed on.
In this context, natural selection emerges as a search protocol for biological meaning. An organism has meaning if it can survive and reproduce in its present environment. Mortal Keats’s ode speaks less to a Grecian piss pot than to life’s bright star, its capacity to persist in endless forms most beautiful, Beauty is truth, truth beauty,—that is all / Ye know on earth, and all ye need to know.
And yet, what of all those other figurines, a litter of forgotten Bauplans, left behind to ashes and to dust or to our imaginations alone? What do they tell us? Phylogenetic and developmental constraints, the idiosyncrasies of all those scale transitions from molecules to ecologies, and the hazards of stochastic chance together embody a taxon-specific syntax that defines the contours of any given population’s phenospace—the combinations of physical, biochemical and behavioral characteristics its members can in actuality express. Such historicity introduces a Gödel-like incompleteness: not all phenotypes, whatever their biophysical qualifications, evolve.
Some species, however, may be able to defy the logic of such a biological incompleteness. High mutation rates, large population sizes both within and among hosts, recombination and reassortment, broad tropism, short generation times, and membership in mutualist guilds render influenza and HIV Turing infections of facultative life histories that simultaneously track an array of fitness maxima. In other words, to their great success pathogens specialize in failing across huge tracts of their phenotypic space.
As a result, the pathogens—with a loose multicellularity but without the physiognomic overhead—can generate solutions to just about any problem of consequence they confront in their corners of the evolutionary space. The resulting variants that work best can be subsequently dispersed just about anywhere in the world by way of host migration, including, today, by humanity’s global travel network.
Such a convergence of pathogenic and sociocultural mechanisms may be so powerful as to represent an evolutionary rocket fuel that permits epidemiological time travel: 1) influenza and HIV infections spread across populations of susceptibles before disease-specific symptoms are detected and 2) circulating strains of both pathogens have evolved drug resistance to novel therapies long before the drugs are first introduced.
The inversions are so integral to their epidemiologies as to represent a not insubstantial breakdown in causality, wherein effects are expected to follow causes. Simultaneous hyperdimensional exploration of many multiple hills across Sewell Wright’s adaptive landscape repeatedly generates the phenotypic results of natural selection before the conditions that select them appear to arise. In a spooky way the bugs can read our epidemiological minds before we recognize our own intentions.
The less stringent temporality that results loosens the pathogens from biological incompleteness and towards a more ontological existence. They can evolve into mind-boggling variants at just about any and all times. The viruses may very well represent a kind of counterintuitive limit case for Darwin’s concept of natural selection by virtue of expressing so much variation, rather than so little.