Biological Vitalism, or What Is Life?

Teleology, Animal Behaviour & Neovitalism

This article was first published in the IM776 magazine and can be found here.

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A spectre has long haunted the field of biology, the spectre of vitalism. In our nominally rational age we are used to describing life as an epiphenomena, one which can be best explained in the language of the machine. Parts, components, software, circuits - these metaphors are a surface deep attempt to ensure biology remains wedded to the Cartesian principles that life, and everything else, can be reduced to its fundamental constituent elements. But this view, more scientism than scientific, has long been contested historically and creaks under the mounting weight of recent evidence. What remains, lurking in the background, is a philosophy of life that seeks to understand the forces, the drives, the will which organises and directs organic matter towards an end. This irreducible, teleological conception of biology can be called vitalism, and I shall attempt to outline the main problems and principles in this brief overview. 

The Problem of Biology

Aristotle knows through various observations that the embryonic parts are not all simultaneously present, but come successively into being; and thus, to use a modern term, we may call his theory "epigenetic". How then do these parts come into being: does the one form the other or do they simply arise one after the other?

The History & Theory of Vitalism, Hans Driesch, 1914. 

The ancient problem of biology is how to explain the difference between animate and inanimate matter? Whilst a simple explanation posits that life is simply stuff which is organised and directed by an external spirit or divine will, observation shows that living organisms ‘unfold’ or develop, from acorn to tree, with some kind of invisible will or direction. Something internal and indivisible. The Presocratic search for the ‘arche’, the underlying principle or substance, led to Thales and Anaximander positing water or fire as the governing element. Onto this Aristotle stamped his theory of hylomorphism - that living beings are composed of both matter and form. To illustrate, a human body after many decades contains none of the same molecules from its infancy, the body is constantly replacing itself. Yet it remains identifiably the same person. The form, the organising directive of the body, stays the same. Aristotle labels this the soul, that force which binds matter and points it towards an end. 

The idea that life requires ‘vital heat’ and water underpinned ‘spontaneous generation’, a theory with remarkable longevity. From the ancient Greeks to Louis Pasteur, people have observed with their own eyes life emerging from mud, foam, decaying matter, stagnant water and even animals changing from one form to another, such as barnacles morphing into barnacle geese. In the most corrupt mediums, life is always present, new forms and shapes coming forth. Debates over spontaneous generation led to the modern hypothesis of ‘abiogenesis’, that life did indeed come from a non-living organic substrate. To paraphrase Georg Ernst Stahl, life is activity and not matter, which is indifferent and simply obeys the organising and governing laws of activity. This conundrum, of form or activity and matter, has not been fully resolved by modern biology. 

The second great problem of biology is teleology. This sounds like a tedious undergraduate seminar topic, but it goes to the heart of why vitalism is still relevant. Under mechanistic and Darwinian principles we cannot say that living beings exist to fulfil a certain goal or end. To most laypeople, the question “what is an animal for?” may sound strange. Animals exist because God made them, they exist to be eaten, to be pets, they exist for themselves and their own mysterious reasons. To a standard biologist life has no reason, no goal, no ends. Life is the product of natural and sexual selection, which blindly and coldly steers different species towards adaptation to their environment. Should that environment change, the ‘blind watchmaker’ pushes them down another path. But this exceptionally dull view of life rests on quicksand. In what has been dubbed ‘irreducible teleology’, the philosophy of biology has failed to jettison goal-driven behaviour from the field. 

Questions over whether traits are selected by evolution because they have a certain function become cringingly tedious. Dawkins went so far as to call Darwinian adaptations ‘designoid’, rather than ‘designed’, such is his fear that the world be seen as alive and full of purposeful beings. 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 latter phrase, while perhaps relished by the more mechanistically minded, obliterates any sentience or intelligence in the thrush, and also fails to capture why the bird migrates. One might retort that the thrush is merely the survivor of those ancestors which initially migrated, but this pushes the problem backwards. Birds, like all organisms, don’t perform random behaviours with the hope their descendents will be better adapted. They pursue their own inbuilt behaviours, innate to them, which always brings in the problem of teleology. As J.B.S Haldane quipped:

Teleology is like a mistress to a biologist: he cannot live without her but he’s unwilling to be seen with her in public.

The Limits of Modern Biology

Biology developed in the opposite way to physics. 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. Physics by contrast has no overarching theory. This has had the effect that new revelations in the biosciences have to 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 ultimately to the genomics revolution of the last few decades. Regardless of how much data has been produced however, the goal of understanding biology has remained elusive. 

Every student of the life sciences is taught a basic axiom of biology, one referred to as the Central Dogma. Put simply - DNA makes RNA, RNA makes proteins. The more nuanced definition is about the flow of information in a biological system. Francis Crick, the originator of the dogma, tried to pin down an absolute law of biology, that information  cannot pass backwards from a protein to the DNA. This 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 and strife 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, classically the example of a giraffe’s neck is used. As the giraffe stretched its neck and lengthened its muscles, so its offspring would be born with a longer neck. The ‘Weissman Barrier’, the separation between bodily cells and those 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 and misunderstood 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 the milk sugar 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. To go further, 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. Much of this sounds depressingly boring but 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 comes down to generational selection of traits which ultimately produce a fitter and better adapted individual. Central to this 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 itself self-direct the course of change, mutations are random, a pool of untapped potential which arises from chaos without guidance. The problem with this is that everything in the cell works 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. The list of genetic diseases is vast, the list of genetic enhancements very small per generation. This matters because life is expressed through different, well defined species, and species are not defined by single mutations like lactase persistence, but rather by their form, their shape and body plan. 

The problem of how species arise suddenly has been debated for decades, with biologists like Stephen Jay Gould proposing theories like ‘punctuated equilibrium’ to explain periods of rapid species diversification. 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 idea 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 vast bloom of different body plans occurred much later in a relatively short period of time. Body plan genes are immensely complex and seem to possess a 4-dimensional quality, allowing an embryo to develop a 3D structure, but also each gene seems to regulate another, unlocking a cascade of perfectly timed regulatory events which allow a blob of cells to differentiate into fingers, eyes, organs and limbs. Any mistake in this sequence can produce a serious flaw in the final overall form. The link between these developmental genes and natural selection doesn’t appear obvious or straightforward, almost any tinkering within this 4D space would have deleterious effects. To quote from 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 Vitalism, Why Now?

Many readers may be thinking that these are all minor issues which will surely be resolved in a few years, so why are we talking about vitalism again? The answer is, as logical positivist Rudolf Carnap admitted in 1934, that the laws which govern natural phenomena seem insufficient to explain biology. 

Let us return to the migrating Wood Thrush. Migratory behaviour is an instinct, a pattern of behaviour which is innate to a species. Like the inborn fear of hawk silhouettes in rabbits or the urge in a beaver to make a dam, 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 simple from the point of view of the biologist. The split between bodily function and behaviour should be dismissed, since 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, the ability for matter to become organised and directed, in a sense demarcate the difference between living and non-living things. Biology seems to defy the basic laws of thermodynamics insofar as it moves towards greater complexity, greater levels of organisation, what Schrödinger called ‘negentropy’ or negative entropy. The Russian chemist Ilya Prigogine worked for decades on the question of how chemical systems can spontaneously produce order under conditions of non-equilibrium. Structures like crystals, tornadoes and snowflakes exhibit this property of self-assembly, even for short periods of time. Life itself seems to arise from the ability of matter to self organise into proteins, cell membranes and the bewildering complexity of DNA, a 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. The 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. In describing the patterns of the developing fruit fly embryo he says: 

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

He later notes that Darwinism as a foundation has major 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 most foundational mathematical interfaces between chemistry and biology, some sort of elusive ghostly residue remains impossible to grasp. This is why vitalism and even animism will never be fully expelled from biology, something seems to ‘will’ order and form onto matter and even if these turn out to be straightforwardly mechanistic in principle, the question still remains of why the laws of physics allows such order to arise. The sceptical materialist will answer that we can only ask this question because we live in such a universe, thus rendering it moot, but this is highly unsatisfactory. Perhaps for some the use of mere language to brush away difficult questions is enough, but for many this type of rhetoric will never suffice. Biology seems haunted by something ‘extra’, some other almost demonic force which drives life to differentiate into species, each one a reflection and manifestation of this underlying Will to Life. The quality and types of life this produces is best left for another time, but hopefully this little introduction to what we could call ‘neo-vitalism’ has sparked in the reader some interest in the age-old basic question of ‘What is Life’?