How the Philosophy of Vitalism Exposes the Limits of Modern Biology
“Teleology is like a mistress to a biologist: he cannot live without her but he’s unwilling to be seen with her in public.”
— J.B.S Haldane
A spectre is haunting the field of biology: the spectre of vitalism.
In our rational age, we are used to describing life in the language of machines. Parts, components, software, feedback, circuits: these metaphors represent an effort to ensure biology remains wedded to mechanistic principles. But still lurking in the background is a counter-philosophy that seeks to understand the force or drive which forms organic matter towards determined ends.
This philosophy is called vitalism. As Hans Driesch wrote in The History & Theory of Vitalism in 1914:
“Aristotle knew through various observations that the embryonic parts are not all simultaneously present, but come successively into being. Living organisms are not inert, but unfold or develop, from acorn to tree, according to some kind of internal direction.”
From the presocratics to Pasteur, people have observed life emerging from mud, foam, decaying matter, stagnant water and even animals transforming, like barnacles morphing into barnacle geese. No matter what the medium, life is always present, surging forth. But what is it?
The Presocratic search for the ‘arche’, the underlying principle of order, led to Thales and Anaximander, who theorised an elemental substance or principle related to fire and water. Aristotle then developed his theory of hylomorphism that living beings are composed of both substance and form.
Modern debates over the dynamics of spontaneous generation have led to the hypothesis of ‘abiogenesis’ which argues that life develops from a non-living organic substrate. To paraphrase Georg Ernst Stahl, life is activity and not matter, which simply obeys the organising and governing laws of activity. But the conundrum of the relationship between substance and the formal aspect of activity has never fully been resolved. A human body, for example, at the point of death contains none of the same molecules that it was born with. In terms of its substance, the body is constantly replacing itself. Yet it remains a single entity because some essential quality remains the same. What is this quality?
The question leads to the second major problem of biology, which is teleology. According to Darwinian biology living beings cannot be said to have a goal or end. Life has no reason, no goal, and no end. Life is the product of natural and sexual selection, which blindly programs random adaptations.
But Darwinian biology has not succeeded in the extinction of the question. The problem of understanding whether traits are selected for by evolution because they have a certain function quickly become extremely intricate. Dawkins went so far as to call Darwinian adaptations ‘designoid’, rather than ‘designed’ to downplay conceptions of purposeful being.
Ernst Mayr showed the difference with two classic sentences:
“The Wood Thrush migrates in the fall in order to escape the inclemency of the weather and the food shortages of the northern climates.”
“The Wood Thrush migrates in the fall and thereby escapes the inclemency of the weather and the food shortages of the northern climates.”
The second phrase obliterates any sentience or intelligence in the thrush, and eliminates the motive why the bird migrates. One can say that the thrush is merely the survivor of the ancestors who first migrated, but this pushes the problem backwards in time. Birds don’t perform random behaviours with the hope their descendants will be better adapted. They pursue their own inbuilt behaviours, innate to them, which always brings in the problem of teleology. This is why J.B.S Haldane quipped that “Teleology is like a mistress to a biologist.”
The Limits of Modern Biology
Biology developed in the opposite way to physics. Whereas physics has no overarching theory, for biologists the ‘Grand Narrative’ of Darwinian evolution came first, and the huge expansion of genetics and molecular science has served to fill in the blanks later.
This has had the effect that new findings in biosciences can be contextualised within an existing theoretical framework. The ‘modern synthesis’ of neo-Darwinism in the mid-20th century successfully integrated Mendelian thought of inheritance with Darwin’s laws of natural selection, and then ‘evo-devo’ in the 1970’s began linking specific genes to the process of organismal development, leading to the genomics revolution of the last few decades. Yet despite the quantities of data this approach has generated, the goal of understanding biology has remained elusive.
Every student of the life sciences is taught a basic axiom of biology, known as the Central Dogma: DNA makes RNA, RNA makes proteins. The more nuanced point concerns the flow of information in a biological system. Francis Crick, the originator of the dogma, tried to codify as an absolute law of biology that information cannot pass backwards from a protein to the DNA. This dogma has served to create the only stable anchor in a field dominated by exceptions to the rules – and yet, it too is wrong.
Darwinism itself was the product of struggle between competing theories of life and nature, one of which was Lamarckism. Lamarck (1744-1829) proposed that organisms gain useful traits throughout their lives which then be acquired by the next generation. The classic example is a giraffe’s neck. As the giraffe stretched its neck and lengthened its muscles, so its offspring would be born with a longer neck.
The ‘Weissman Barrier’, the theory of a separation between bodily cells and germ cells which lead to embryo formation, squashed Lamarckism for generations (outside of the Soviet Union), but Lamarck has had something of a renaissance with the discovery of epigenetics.
Epigenetics is a complex term, but it refers to the system of biological mechanisms which control DNA expression and how changes to these mechanisms can be inherited. For example, the ability to digest lactose is dependent on the organism producing the enzyme lactase. Lactase production is controlled by a series of molecular ‘switches’ which ‘turn on’ lactase production during infancy and then ‘turn off’ production as the organism weans off milk onto other foods. In a famous 2013 study, mice were trained to fear a particular smell, the offspring of these mice also feared the same scent – a genetic memory attributable to epigenetic modifications. These heritable changes to the epigenome need not alter the DNA directly, but they can profoundly affect the resulting phenotype. Epigenetic modifications can become assimilated into the genome under certain conditions. Similarly, a whole host of proteins and transcriptional factors exist which make the causal determinism of the Central Dogma untenable: reverse transcriptase, RNA splicing proteins, prions, integrase enzymes, and so on.
The ramifications are immense. Darwinian biology is predicated on the idea that information flows in one direction, that an organism is controlled by the expression of genes which are preserved as DNA sequences in the genome. How organisms adapt is conditioned by the generational selection of traits which responding to environmental pressures produce a fitter and better-adapted organism. Central to this model is the notion that traits arise from mutations and genetic diversity already present within the genome. What cannot be allowed is that the environment and organism self-direct the course of change.
Mutations must be random, a pool of untapped potential which arises from chaos without guidance. Yet everything within the cell itself is geared against this premise. Intricate proofreading machinery guards DNA against mutations, damage can be repaired, and when mutations do appear they are overwhelmingly deleterious or lethal. Every generation, the number of genetic diseases is very large and the number of genetic enhancements are very small. This matters because life is expressed through different species, and species are not defined by individual mutations, but rather by their form.
The problem of how species originate has been debated for decades, with biologists like Stephen Jay Gould proposing a theory of ‘punctuated equilibrium’ to explain periods of rapid speciation. Exactly how novel complex species appear in the fossil record is still argued over today. Events like the Cambrian Explosion, the Devonian land plant or the Cretaceous flowering plant explosion seem to defy the model of a regular, steady beat to evolution. The genetic developmental mechanism, the Hox genes, were well established prior to the Cambrian Explosion, and yet the explosion of diverse physical forms occurred much later in a relatively short period of time.
Physical genetics is immensely complex and seems to possess a four-dimensional quality, allowing an embryo to develop a 3D structure in which each gene regulates another, unlocking a cascade of perfectly timed regulatory events which enable clumps of cells to differentiate into fingers, eyes, organs and limbs. Any mistake in this sequence can produce major flaws in the ultimate form. The link between these genes and Darwinian natural selection is not obvious: almost any tinkering within this 4D space creates deleterious effects.
To quote Simon Conway Morris in the excellent 2003 book Origination of Organismal Form Beyond the Gene in Developmental and Evolutionary Biology:
“But the reverse is also the case, whereby phenotypic diversity emerges from a conserved genomic framework. A striking example comes from the arthropods. Averof (1997) reminds us that the identical complement of Hox genes, which in arthropods underpins their axial reorganization, seems to have no obvious bearing on the widely varying degrees of tagmoses and segment organization. Thus, although genome arrangements and duplications must provide an important basis for metazoan diversifications, the fundamental patterns continue to elude us.”
Why is any of this relevant? The central point, as logical positivist Rudolf Carnap admitted in 1934, is that the laws which govern natural phenomena seem insufficient to explain biology.
To go back to the migrating Wood Thrush. Migratory behaviour is an instinct, a pattern of innate species behaviour. Like the inborn fear of hawk silhouettes in rabbits or the urge in beavers to make dams, these are not partial drives or confused images, these are fully operational and help guide an organism to food, mates and safety. But instincts are not easy to explain.
Instincts grab the entire body and direct it toward an end. The physiology of the organism can be rearranged for a time period, hierarchically managed by some governing pattern: fear, attraction, hunger. But as Arguello & Benton state in their 2017 paper: “All of us have marvelled at the remarkable diversity of animal behaviors in nature. None of us has much idea of how these have evolved.”
These patterns demarcate the difference between living and non-living things. In this way, biology seems to defy thermodynamics since it moves towards complexity, and greater levels of organisation against what Schrödinger called ‘negentropy’ or negative entropy.
Chemical systems can spontaneously produce order under conditions of non-equilibrium: structures like crystals, tornadoes and snowflakes exhibit this property of self-assembly. Life seems to arise from the ability of matter to self-organise into proteins, cell membranes and the bewildering complexity of DNA, this molecule which physically encodes the information needed to create shape, form and the higher processes of an organism. Even without ascribing an external spiritual force, it seems that the laws of physics allow for and even drive towards the development of complex structures.
Mathematical biologist Stuart Kauffman argues in his 1993 book The Origins of Order Self-Organization and Selection in Evolution that this capacity for matter to self-organise should be considered a separate force in biological evolution, alongside natural selection, providing the underlying structure for life:
“Therefore, it is terribly striking that a number of the maternal, gap, pair-rule, and segment-polarity genes do actually come to exhibit complex, multipeaked longitudinal patterns of RNA transcripts and protein abundance in the syncytial egg. Whatever the mechanism governing the patterns, the phenomena are truly beautiful.”
Kauffman also notes Darwinism has fractures in its base, saying “we do not understand the sources of order on which natural selection was privileged to work.”
These sources of order seem to include beauty and symmetry in their deepest origins. No matter how much detailed work is done on the foundational mathematical interfaces between chemistry and biology, an elusive ghostly residue remains impossible to grasp. This is why vitalism and even animism will never be fully expelled from biology. Something awesome and mysterious orders living matter. A force which drives life to differentiate into species, each one a reflection and manifestation of itself.