2015-09-24 (Warsaw) Human Nature after Neo-Darwinism

The quest for human nature is, for more than one reason, not an easy task. One of those reasons is that both the subject and the quest are not fixed, but have a long history. Concerning the subject, human nature is part of - and therefore cannot be isolated from - the evolution of life on earth, which started about four billion years ago and will probably continue long after and beyond the human being. And although almost negligible compared to the ‘deep time’ of earth’s life, man himself (the biological species Homo sapiens sapiens, whose ancestors entered the evolution of life about 2,3 million years ago), is marked by a – in this case both natural and cultural - history as well.

Moreover, the raise of historical consciousness in the natural sciences, social sciences, and humanities in the last two centuries has changed the very question concerning human nature. Until and throughout the 18th century still, human nature was predominantly understood as a fixed essence. Even a skeptical mind like David Hume did not doubt this static conception. In his Inquiry Concerning Human Understanding (1748) we read: “Mankind are so much the same, in all times and places, that history informs us of nothing new or strange in this particular. Its chief use is only to discover the constant and universal principles of human nature”.[1]  For us, in our current era, the issue no longer seems to be the discovery of the unchangeable essence of humanity, but rather to explain its very changeability, as it is expressed in the overwhelming variety of human cultures throughout the course of human history. Of course, we can define this changeability itself as an essence, but in that case we arrive at rather abstract definitions, like the one Helmuth Plessner provides in Die Stufen des Organischen und der Mensch (1928), when he characterizes man as “artificial by nature”. Being excentric, man is pressed “towards ever different realizations” of himself, and for that reason “leaves a history behind himself”.[2] As a consequence, according to Plessner, the quest for human nature cannot refrain from the empirical study of those different realizations in time and space.

However, there is an additional reason why questioning human nature is such a difficult endeavor. Even when we restrict our inquiry into human nature to a description of one particular realization (be it a particular culture or even a single person), we find ourselves overwhelmed by the complexity of the human life form. Human life consists of many, often interrelated dimensions, ranging from its biological, psychological, sociological and political characteristics to various artistic, religious, moral, and scientific activities as well numerous cultural and technical artefacts and institutions. As a result, human nature must be studied from the points of view of a variety of natural and social sciences (such as biological anthropology, neuroscience, psychology, sociology, political science, cultural anthropology), as well from those of humanities (history, archeology, literature, law, cultural studies, theology and philosophy, etc.), in order to account for its rich complexity. Moreover, the quest for human nature is not restricted to sciences and humanities. Many of the activities that are part of human nature, such as artistic expression and religious contemplation, consist of reflections on human nature as well. Self-reflection is an inherent aspect of the ex-centric character of the human lifeform. In addition, self-reflection is generally considered to be a sine qua for the good life. In the often quoted words of Socrates: “an unexamined life is not worth living.”[3]

The many interrelated dimensions of human life are indicative of the complex texture which we call human nature. Although in the history of human self-reflection often one particular dimension has been emphasized – one may think of attempts to define man as a zoon politikon, an animal rationale or symbolicum, or as a Homo sapiens, faber or ludens – in reality we cannot reduce the complexity of human nature to one of these constitutive dimensions.

Nevertheless, in this essay I will focus on one particular biological determination of man: the Neo-Darwinist account of human nature. After my introduction, it will be clear that this choice does not imply that I endorse this Neo-Darwinist account of human nature. On the contrary, in this paper I will criticize Neo-Darwinism because it reduces human nature to its molecular basis, and more particularly to genes, which are considered to be the final determinants of human life. The reason to focus on Neo-Darwinism is that in the past decades this reduced and, for that reason, impoverished image of human nature has become immensely popular, not only in evolutionary biology and the connected life sciences, in which it is still, to a large extent, the dominant paradigm, but also in the social sciences and the humanities, ranging from evolutionary psychology and economics to evolutionary ethics and aesthetics. Moreover, due to bestsellers like Richard Dawkins’ The Selfish Gene[4] , which sold over one million copies since its publication in 1976, the Neo-Darwinist image of man became part of popular reflection on human nature far beyond academia.

The rise of Neo-Darwinism didn’t come out of the blue. It is part of the process of naturalization and mechanization of the worldview which has characterized Western modernity since the 16th century. This tradition has not only led to a disenchantment of living nature surrounding human beings, but has also profoundly affected our view on human nature, and of the human place in the cosmos. Neo-Darwinism, which culminated in the 20th century in the so-called Modern Synthesis of evolutionary theory and molecular genetics, did not only question the alleged gulf between human beings and other animals (as Darwin already did), but even the very gulf between animate and inanimate nature. The result is a reductionist, deterministic and even nihilistic image of man, leaving little room for meaning, morality and art and other dimensions of human life that have long been considered to be important if not crucial aspects of understanding humanity.           

In the Western World, the ‘greedy reductionism’ of Neo-Darwinism has met severe criticism, especially from representatives of Christian and humanistic traditions. However, as these criticisms are often motivated by a no less ‘greedy transcendentism’, they fail to convince those who adopt a modern, scientific world view.[5]  However, in the last decades there is also a growing body of critique of Neo-Darwinism emerging from biologists. In their view, recent developments in epigenetics and systems biology necessitate a fundamental reconsideration of some of the basic presuppositions of Neo-Darwinism. Although at first glance these discussions are rather technical and specific in scope, they have far-reaching implications for human self-reflection

In what follows I will first situate the so-called Modern Synthesis of Neo-Darwinism in the history of modern biology. Whereas Darwin developed a broad definition of evolution, in which the environment plays an important role, in the dominant Neo-Darwinist paradigm the notion of evolution was narrowed down to radical gene-centric view.  Next, I will discuss the paradigm shift which it taking place today in ‘postgenomic’ evolutionary biology and genetics. This shift opens the way to a more humane conception of evolution, more in line with Darwin’s view. Finally, I will discuss some of the implications of this paradigm shift for human self-reflection taking The Music of Life. Biology Beyond Genes of systems biologist Denis Noble as a starting point.[6]

1.      The Modern Synthesis of Neo-Darwinism

The static image of man, as expressed by David Hume in 1749, gradually changed in the second half of the 18th century. Discoveries in the natural sciences and the development of archeological and historical research evoked the awareness that both nature and culture have a much longer history than the four thousand years that has been previously estimated taking the Bible as authority. Especially the discovery of the so-called ‘deep time’ in geology motivated a fundamental historization of our worldview.

This historization also affected the study of living nature. Whereas Hume’s contemporary  Linnaeus (1707-1778), who prepared the way for modern biology, still presented a rather static classification of nature in his Systema Naturae (1735), one generation later Jean-Baptiste Lamarck (1744-1829) developed the first consistent evolutionary theory in his Philosophie Zoologique (1809), stating that all species develop from previous ones.[7]  Lamarck distinguishes two forces he saw as comprising evolution; a life force (Le pouvoir de la vie), driving animals from simple to complex forms, and a force adapting animals to their local environments and differentiating them from each other (L’influence des circonstances). With regard to the impact of the environment, Lamarck distinguishes two related laws. The first one states that a more frequent and continuous use of any organ gradually strengthens, develops and enlarges that organ, while the permanent disuse of any organ imperceptibly weakens and deteriorates it, until it finally disappears. The second law states that such acquired characteristics are reproduced in the offspring.

This law of the inheritance of acquired characteristics – the often quoted example being the long neck of the giraffe, which, according to Lamarck, evolved because generations of giraffes reached for ever higher leaves – gained a certain degree of popularity in the course of the 19thcentury. We even find it in Charles Darwin’s The Origin of Species (1859), in which he repeatedly and approvingly refers to Lamarck’s laws, including the giraffe example.[8]  However, Darwin also developed a complementary explanation, his theory of natural selection.  This theory – according to Daniel Dennett the best and most ‘dangerous idea’ ever[9] – states that a simple mechanistic algorithm of reproduction, variation and selection is responsible for the entire evolution of life on earth. Unlike Lamarckian evolution, which is the result of a fast, discontinuous, and purposive adaptation, Darwinian evolution is a slow, gradual, and random process that takes many thousands of generations.

Lamarck’s popularity ended quite abruptly after the publication of the experiments of the German biologist August Weismann, who tested Lamarck’s theory of the inheritance of acquired characteristics with a rather cruel experiment. After cutting off the tails of 68 white mice repeatedly over 5 generations, and observing that no mice were born without a tail or even with a shorter one in consequence, he concluded that hereditary information moves only from germline cells to somatic cells, and never in reverse. This thesis, known as the Weismann barrier, effectively banished Lamarckism from mainstream biology, including the Lamarckian elements in Darwin’s evolutionary theory, shifting the focus exclusively on natural selection.

However, although Darwin successfully described the process of natural selection, he was not able to explain it. He was not aware of the publications of his contemporary Georg Mendel, in which he reported his experiments with the genetic traits of peas. Mendel discovered that genetic traits consist of discrete units (for which the Danish botanist Wilhelm Johannsen introduced the word “genes” in 1909), the inheritance of which follows specific mathematical laws. Mendel’s discovery inspired the development of modern genetics. Especially the so-called population genetics of the 20s and 30s of the 20th century played an important role in this development by synthesizing Darwinian evolutionary theory and Mendelian genetics, and giving it a robust mathematical foundation. Julian Huxley’s book Evolution, the Modern Synthesis gave this Neo-Darwinian project its name.[10]

However, the real breakthrough of the Modern Synthesis followed after the discovery of the material substrate of the gene, the DNA molecule in the cell nucleus, by Francis Crick and James Watson in 1953. This large double helix molecule, which consists of about three billion nucleotides in four different variants, was supposed to code for all of the genetic traits of the organism. DNA plays a crucial ‘vertical’ role in that the encoded genetic traits in the reproduction are transferred to the offspring. However, it also plays a no less crucial role in the construction and regulation of the organism, because the code is used to produce, via a transcription into messenger RNA and a subsequent translation into a protein, of more than 100,000 different kinds of proteins. These proteins function as the building blocks of the organism, as its fuel, as enzymes in the digestion of food and damaged tissues, as means of transport of chemical substances through the body, as hormones in the regulation of bodily processes, and as anti-bodies in the immune system.

The discovery of DNA and the subsequent research of its functioning made it possible to explain the variations in offspring discussed by Darwin in his theory of natural selection. These differences are not only the result of the recombination of genetic traits of the parents through sexual reproduction, but account for traits which are also subject to small changes because of mutations due to copy errors –because of radiation, for example – during the reproduction of the genes. The resulting differences may be disadvantageous for the offspring (for example if they lead to the malfunctioning of specific organs), but they can also lead to a greater reproductive success and biological fitness. Within this Neo-Darwinian perspective, the longer neck of the giraffe is not the result of intensive use of the neck, but the outcome of a long series of small mutations.

Neo-Darwinism also reinforced the Weismann barrier and the ban on Lamarckism, by the formulation of a so-called ‘central dogma’. This dogma, formulated by James Crick in 1956, states that genetic information flows exclusively from DNA via RNA to proteins, which can then form protein networks, and so on up through the biological levels to that of the whole organism, but can never flow the other way.[11]  Although it is true that proteins cannot code for DNA, the ‘central dogma’ soon was interpreted in a much broader way. Following Weismann, it was taken to mean that the organism and its environment cannot have any influence on the expression of the genes. This strict separation of the germline cells and soma cells – the implication of the Neo-Darwinian identification of genetic traits with specific sequences of nucleotides in the nucleus – lead to a gene-centered, strongly reductionist and determinist notion of evolution and genetics. After having been developed by George Williams in his book Adaptation and Natural Selection[12], this gene-centered view was especially popularized by Richard Dawkins in The Selfish Gene.[13]According to Dawkins’ account the organism is nothing more than a temporary vehicle for the reproduction of immortal selfish genes. Although Dawkins does not talk a lot about humans and even explicitly states on the very last page of his book that, although “we are built as gene machines and cultured as meme machines, [but we] have the power to turn against our creators”, and that “we, alone on earth, can rebel against the tyranny of the selfish replicators”[14], the extreme reductionist and determinist exposition on the preceding 200 pages does not offer even the beginning of a clue about how this could be possible. The impression we are left with after reading the book is that of a rather pessimistic nihilism.

Surprisinly, this did not temper the enthusiasm for the Neo-Darwinian project. As Sarah Richardson and Hallam Stevens write (with a strong sense of irony): “The discovery of the double-helical structure of DNA in 1953 lit the flame. The breathtaking rapidity with which this discovery lead to the entrenchment of the central dogma (DNA→ RNA→ protein), the cracking of the genetic code, the emergence of genetic engineering technology, and the early understanding of Mendelian diseases created an expectation of exponential increases in our ability to measure and interpret DNA information. DNA satisfies the compulsions of many scientists: measurable, discrete, molecular (yet apparently integrative), deterministic, and evolvable. If a little DNA sequence was good, then a lot—the genome—would be great. With the prospect of greatness, reasonable people are prone to hyperbole: save money, develop cures, predict disease, learn about our ancestors, and bring justice to all. It can be hard to judge harshly someone in love”.[15]

2.      Biology beyond genes

Inspired by these hyperbolic expectations, quite a lot of money and energy has been invested in the Humane Genome Project (1990-2003). Due to the joint effort of thousands of researchers all over the world the sequencing of the entire human genome was realized in an impressively short period of time. However, in the light of the high expectations, the result was for several reasons somewhat disappointing.

First, the number of genes in the human genome turned out to be much smaller than expected. Instead of 100.000 genes (the number of different proteins), the number turned out to be about 20.000. Apart from the fact that this modest number offended human narcissism (the tiny, unicellular Protozoa, for example, already has three times more genes than Homo sapiens sapiens), it also made clear that the “one gene, one function” credo of Neo-Darwinism was incorrect. Most human genes do not code alone, but function in large genetic networks, and depending on the network, they can execute multiple functions. The number of possible combinations of 20.000 genes is hyper-astronomical. Mathematicians call it a combinatorial explosion, and the number of combinations is not only far beyond our imagination but even beyond the number of particles in the universe.  

Second, not all genes express themselves in proteins. They can be ‘switched’ on or off. The non-coding part of the DNA– about 98,5%, initially termed junk-DNA because it was thought to have no function, - turned out to have all kinds of regulative functions regarding the gene expression. Whereas it was expected that the Humane Genome Project would crown the Neo-Darwinian project, it became clear that, although determining the sequence of four DNA bases turned out to be relatively easy, the understanding its role in biological systems is incredibly challenging[16] . Although impressive in many respects, the Human Genome Project marked a new beginning rather than the end of genetics.

Moreover, some recent developments in so-called ‘postgenomic’ research not so much urge to extend Neo-Darwinist theory, but conversely, undermine some of its basic presuppositions.[17]

 First of all, it turned out that mutations are not random. The speed, amount, and the location of genome change can be influenced functionally.[18]  The immune system, for example, is able to react to many different antigens. This kind of natural genetic engineering is not restricted to the immune system, but plays also a role in the development of organic functions and explains the non-random number of limbs, digits, segments, and vertebrae across a variety of taxa. The development of life is a constructive process, as the organism shapes its own developmental trajectory by constantly responding to, and altering, internal and external states.[19]

Secondly, genetic change is not gradual. Often whole sequences of DNA, containing multiple genes, are transposed to another part of the genome. These mobile genetic elements, sometimes called ‘jumping genes’ - already discovered by Barbara McClintock in 1951 but neglected for a long time - are not rare, as recent research demonstrates. Over two-thirds of the human genome is derived from mobile elements.[20]  Moreover, such genetic cut and paste work in most cases is not once-only. For a large part, the genome consists of semi-stable genetic elements that may be rearranged or even moved around in the genome, thus modifying the information content of DNA.[21] These rearrangements are the result of active manipulation by the cell’s enzymes. This constant interaction between the germline (the genes) and somatic elements fundamentally undermines the central dogma of the Modern Synthesis.[22] 

Moreover, the ‘jumping’ of the genes is not restricted to transpositions within the genome, but also takes place between species. In the case of prokaryotes (unicellular organisms without a nucleus) this kind of horizontal transfer of genetic material takes place quite frequently, but it also happens quite often in the case of eukaryotes (cells with a nucleus). Many elements of the eukaryotic cell (such as the mitochondria) initially were bacteria that invaded the cell, but became part of it and contributed their DNA to the cell. For that reason the ‘tree of life’ is actually a ‘network of life’.[23]

Thirdly, given the fundamental Neo-Darwinist rejection of Lamarckism, the most remarkable development in the postgenomic era is the rehabilitation of the ‘inheritance of acquired characteristics’ in epigenetics, a generic term for all kinds of inheritance that does not involve a change in the sequence of DNA. “These include components of the egg and post-fertilization resources (e.g. hormones), behavioral interactions between parents and offspring (e.g. maternal care), parental modification of other components of the biotic and abiotic environment (e.g. host choice) and inheritance of symbionts directly through the mother’s germ cells or by infection”.[24]  Under this broader notion of heredity, inheritance can occur from germ cell to germ cell, from soma to germ cell, from soma to soma, and from soma to soma via the external environment.[25]

A spectacular example of genetic research is an experiment performed by Sun Yong-Hua in Wuhan, China, who used the nucleus of a carp inserted into the fertilized but enucleated egg cell of a goldfish. Whereas, on the basis of the central dogma, one would expect a carp, actually the offspring was a hybrid that in several respects was closer to a goldfish than to a carp.[26]  These kinds of epigenetic effects are also demonstrable in humans. A study done in in Scandinavia clearly shows the transgenerational of food availability to human grandparents influencing the longevity of grandchildren.[27] A no less striking example of a study of epigenetic inheritance independent of the germline showed that the stroking and licking behavior by adult rats towards their young results in epigenetic behavior epigenetic marking of the relevant genes in the hippocampus that predispose the young showing the same behavior when they become adults.[28]

A last example of epigenetic inheritance I want to mention concerns a remarkable experiment with mice by Larry Feig. During their adolescence, the mice were put in an environment, enriched with social interaction and different toys. It was not surprising that their memory functions were better developed than those of the mice kept in a stimulus poor environment. However, what was surprising was that the next generations had better memory, too, even when they did not grow up in an enriched environment.[29]  The study of inheritance of acquired reaction against viral infections by C. elegans (a small worm often used in genetic research) showed that this epigenetic mechanism was robust for over 100 generations.[30]

All of the empirical findings discussed necessitate a fundamental revision of the Neo-Darwinian paradigm. In the last part of this essay I will discuss some aspects of this revision, focusing on their implications for human nature and human self-reflection.

3 Some implications for human nature and human self-understanding

Among the critics of Neo-Darwinism, the physiologist Denis Noble from Oxford University, renowned for his mathematical models of the heart and pioneer of the field of systems biology, is an interesting voice for more than one reason. Although as a biologist he was raised in the tradition of Neo-Darwinism, his work on the complex feedback systems of the heart questioned some of their reductionist presuppositions, and he gradually became one of the most vehement critics of Neo-Darwinism. Guided by the credo that Darwin himself - accepting Lamarckian inheritance of acquired characteristics as a complement of natural selection - was not a Neo-Darwinist, Noble became a passionate advocate of a replacement of the Modern Synthesis by what he calls an Integrated Synthesis.

In 2006, he published The Music of Life. Biology Beyond the Genome.[31]  This book, a second reason to refer to Noble, is composed as a critical counterpart of Dawkins’ The Selfish Gene, which celebrated its 30th anniversary that same year. Just like Dawkins, Noble has written his book for a general audience and like Dawkins, he masterfully deploys metaphor to convince his readers. We should realize that this is not a trivial fact. Both in science and in everyday life metaphors do not just have an ornamental function, but a transcendental one as well: they structure and motivate our thinking and action.[32]

In The Music of Life Noble confronts the metaphor of the selfish gene with an alternative one: life is like a piece of music. This metaphor enables Noble to criticize Dawkins’ ontological reductionism. Just as a piece of music cannot be reduced to the score, life cannot be reduced to the DNA code. Stating that the DNA code ‘causes’ life is as absurd as supposing that the digital code on the CD ‘causes’ Schubert’s piano trio Noble argues. Without a CD player the CD can do nothing.  Actually, the 20.000 genes in the nucleus function rather like the pipes of a large organ, which do nothing on their own, but need an accomplished organist to make the organ play and bring the music to life. Likewise, genes do things on their own, but have to be ‘played’ by the organs of the organism. The genome is not a program, that builds and instructs the living body, but rather a vocabulary, that needs a competent speaker in order utter meaningful sentences.[33]

However, Noble’s musical metaphor is even more fruitful than the linguistic one, because unlike spoken language, which is, like the genome, sequential, most music is polyphonic and is played by multiple instruments, belonging to different groups, such as strings, brass and wood-wind instruments and rhythm instruments. The same goes for the music of life, which consists of the close cooperation of many organs and systems. Like an orchestra, the body is an organic whole, and like a symphony, life consists of many different movements. Moreover, unlike a meaningful text, a piece of music does not necessarily have semantic value. Unless it is a song, it is a teleological whole without linguistics, a language without words. We find a similar idea expressed in Wilhelm Dilthey’s ‘hermeneutics of life’, when he writes: “Lived experiences are related to each other as motifs in an andante of a symphony: they are unfolded (explication) and what has been unfolded is then recapitulated or taken together (implication).”[34]

The “grand composer” of the music of life is evolution Noble adds: “It has orchestrated the music of the genes, the harmony of the cells, the symphony of the various stages of life. It has achieved this by serendipitously winnowing down the possibilities”.[35]  However, like every metaphor, Noble adds, the metaphor of the music of life has it limits. Unlike a symphony of, let’s say Beethoven, the Symphony of Life on Earth was not a creation by a conscious, divine composer. Says Noble: “The grand composer was even more blind than Beethoven was deaf!” [36]

However, as the postgenomic research has shown us, although the mechanic algorithm of the natural selection – variation, reproduction, selection –is an essential driving force in evolution, it is not the only one. Just as in the performance of a symphony, organisms need a conductor. “Any well-regulated biological system must involve feedback controls”.[37]  However, unlike in the case of the classical orchestra, with the organism, the conductor is not a separate individual, but rather the network as a whole: “There are no privileged components telling the rest what to do. There is rather a form of democracy, with every element at all levels having a chance to be part of a regulatory network. The coordinating hand is not so much an organist’s as a conductor’s. Or perhaps we should think rather of a ‘virtual conductor’- the system behaves ‘as if’ it has a conductor. The genes behave ‘as though’ they are being played by this conductor – like some orchestras that play without a separate conductor”.[38]

Indeed, a simple organism looks more like a jazz combo than like a classical orchestra. However, as they are autopoetic, teleological feedback systems, organisms organize themselves in the course of evolution to ever greater complexity. In this sense, the history of music resembles the history of life on earth. Both musical practice and evolution evolve. Whereas traditional music often is played without a conductor and written scores, the growing complexity of music led to the use of a written score and the emergence of a conductor. Likewise, in evolution the DNA code is a relatively late development. And it is not before the emergence of the nervous system that a separate conductor enters the stage, culminating in consciousness and self-consciousness: a ‘feedback system’ which, finally, endows Homo sapiens sapiens with the biotechnological control of organic life, including its own lifeform. Natural evolution evolves into technological revolution. Man may turn out to be the first species on earth to construct its own evolutionary successor.

One of the key concepts Noble develops in this context in the The Music of Life is ‘downward causation’. The fourth chapter is actually called “The Conductor: Downward Causation”. The concept of downward causation refers to the feedback mechanisms in the organism. Higher organizational levels in the organism, such as tissues, organs and finally the organism as a whole, trigger and influence action at the lower levels. This idea of downward causation is connected to the notion of strong emergence. “When aggregates of material particles attain an appropriate level of organizational complexity, genuinely novel properties emerge in these complex systems.” These “emergent properties are irreducible to, and unpredictable from, the lower-level phenomena which they emerge”.[39]  The example worked out in detail by Noble, is the rhythm of the heart, which is not the work of some (metaphysical) vital force, but neither can be reduced to a specific ‘oscillator gene’ or other lower-lever causal force. Actually, the heart rhythm is an emergent property of the organ as a whole. Of course, Noble does not deny upward causation, but his Integrated Synthesis implies that life involves both bottom-up and top-down causation. In a later article Noble connects this to what he calls “the principle of biological relativity”, the idea that in living systems there is no privileged level of causation.[40]

It is especially this plea for ‘strong emergence”[41] , which contrasts Noble’s Integrated Synthesis with the reductionist paradigm of Neo-Darwinism, and of reductionist natural science as whole. Strong or ontological reductionism claims that all phenomena can be reduced to the level of elementary particles. It asserts, in other words, that the whole really is, in the final analysis, nothing but the sum of the parts and can be fully explained on this level. Physical systems are causally closed, there is no room for additional principles to operate.[42]

However, one way or another, strong reductionism must be incorrect, as downward causation not only seems to be evident in all living systems, but is part of everyday human experience. My intention to raise my hand evidently triggers and influences the movement of my body. As the French philosopher of science Michel Bitbol formulates this paradoxically: “Downward causation looks impossible as a concept, but is well established as a fact”.[43]

Several attempts have been made to solve this paradox, for example by appeal to quantum physics indeterminism or intrinsic imprecision of the laws of physics due to the finite computational resources of the universe. Maybe the most promising perspective is to consider the universe as an open system, which “would enable ‘external’ or global principles to ‘soak up’ the slack left by the openness”.[44]   It could also explain the radical openness that characterizes human nature and the fact that humans are ‘artificial by nature’. However, it is clear that many questions are still open here, and I don’t have the pretension to be able to solve them.

Instead I will make some concluding remarks on the impact of the Integrated Synthesis proposed by Noble for human self-understanding. What it makes clear first and foremost is that genes do not solely determine our life. Nor are we sheer vehicles for their reproduction. Noble summarizes this pointedly by rewriting a key passage from The Selfish Gene, in which Dawkins characterizes genes as follows: “Now they swarm in huge colonies, safe inside gigantic lumbering robots, sealed off from the outside world, communicating with it by tortuous indirect routes, manipulating it by remote control. They are in you and me; they created us, body and mind; and their preservation is the ultimate rationale for our existence”.[45]  In Noble’s rewriting, the passage now reads: “Now they are trapped in huge colonies, locked inside highly intelligent beings, moulded by the outside world, communicating with it by complex processes, through which, blindly, as if by magic, function emerges. They are in you and me; we are the system that allows their code to be read; and their preservation is totally dependent on the joy we experience in reproducing”.[46]

 However, as life consists of both downward and upward causation, it is clear that we are not autonomous agents that have complete control over our lives. We are controlled by lower level processes as much as we control them. Many diseases have genetic components, our drives often are not under rational control, and the physical and social environment have a strong influence on our thinking and actions as well. In light of this human agency is autonomous in the sense Descartes and Kant thought it was, believing in a mind residing somewhere beyond our bodily existence. Human freedom seems to be more restricted.

Maybe a more realistic account of human agency can be found in Greek tragedy. We may think about Medea, standing next to her children with the knife in her hand, wrestling with her daemons that are trying to take over her actions.[47]  Medea is torn between the love for her children and the feelings of revenge towards her husband, who has humiliated her deeply by leaving her for another woman and is about to expel her from the country as an unwanted stranger, which will certainly result in her being murdered (both events sound quite topical in our ears). Medea is a tragic heroine, not because of her intense suffering (not all suffering is tragic), but because she takes responsibility for her decision to accept her daimon of revenge, the benign nature spirit, who prompts her to kill her children, as part of her own. Medea cannot be called free as neither the situation nor her character was chosen by her. In that sense, she was not free to choose whether to kill her children or not. Her daimon was too strong for this to happen. But this did not imply that Medea had not choice whatsoever. She could choose to ‘go along’ with her daimon, or to resist it in some way or other. By accepting the daimon as her own daimon, Medea took “responsibility without freedom”.[48] That choice, we might add, is what constitutes Medea as a moral subject.

It is this kind of tragic agency – which we also find in Nietzsche, a notion which is connected with his admiration of the tragic worldview of the Greeks – which makes us human. The idea of being completely determined by external forces – be it in the form of religious fatalism or genetic determinism undermines this tragic humanism.

In human beings, the ‘music of life’ becomes a tragedy or opera in the sense that the music now is supplemented by narrative, and thus with meaning and reasons. In human nature downward causation takes the form of steering one’s life with the help of meaningful narratives (whether artistic or scientific), consisting of motives, reflections and reasons. Both Dawkins and Noble organize the results of biological research in a metaphorical narrative. The scientific facts and the narrative are mutually constituting, like the Forschung and Darstellung in historiography. As such the choice of narrative is crucial for the way we self-reflectively constitute identity. Some metaphors are better than others, both in the sense that they might be more adequate vis a vis the biological facts, and in the sense that they may be more desirable from a normative point of view.

In my introduction, I pointed out that reflections on human nature may range from Homo sapiens to the life of a single person. Let me, as a kind of coda, conclude my reflections on human nature with the tragic story of the Dutch literary author Joost Zwagerman, who committed suicide on September 8, 2015, at the age of 51, leaving behind three children, a girlfriend, relatives and many friends. Joost Zwagerman was a popular author of successful novels, poetry, and essays, translated in a dozen languages. As a regular guest in television shows, he was a kind of celebrity and his suicide – one day before the release of his new book, The Silence of Light – shocked the nation. One of the reasons of the perplexity his death caused was that Zwagerman was also known for his firm rejection of suicide. In 2005, after his father attempted to commit suicide, Joost Zwagerman published a book on this subject in which he focused on the dreadful effects suicide has on the bereaved. Although he was very open about the fact that he suffered from depression, nobody expected that he would come to commit suicide. A couple of days after his death a magazine published the last interview Zwagerman has given, on his own initiative, and one of the main subjects in the interview was suicide.

After the interviewer mentioned the suicide attempt of his father, Zwagermans says: “Everybody sometimes will think: if my life will become miserable, I might step out of it. This is typically human. Many will have these kind of comforting thoughts. In the small book I wrote about this subject in 2005 I quoted Nietzsche: ‘Der Gedanke an den Selbstmord ist ein starkes Trostmittel: mit ihm kommt man gut über manche böse Nacht hinweg.’ [The thought of suicide is a powerful comfort: it helps one through many a dreadful night.] After my father attempted to commit suicide, this thought no longer comforts me. The attempt of my father is too emotional, and the idea that the inclination to commit suicide is sometimes genetically transferred from one to the next generation, is terrifying. Not only with regard to myself, but especially when I think about my children and my future grandchildren and great-grandchildren. I wish I could personally remove this gene from our family tree. Because when the thought of suicide pops up in my mind, if only for a second, I immediately think: oof, my father’s genes”. After the interviewer interrupts him with the question if he had ever considered suicide, he answered: “Absolutely, but only as a comforting thought. Later I have made a taboo of it. It really has always been a no-go area for me. Especially because of my children. I have attempted to write it away en to look the monster right in the eye. This book has been the only book […] I wrote for a specific class of readers, namely the bystanders, the bereaved after a suicide. I wrote it for my mother, and maybe it has comforted her”.

Of course, I’m not claiming that the human condition as described by Neo-Darwinism has caused Zwagerman’s suicide. Such tragic events have multiple and often complex reasons. In the interview, Zwagermans also speaks of the regret caused by his divorce, and he also reveals that he suffered from Bekhterev's disease, a chronic inflammatory disease of the axial skeleton. However, the way he emphasizes an alleged genetic curse that might cause him to commit suicide, sounds like a self-fulfilling prophesy.

Although our life is not a story, quest of narrative[49] , and the way we narrate our lives makes a difference. Narratives are our way of conducting our lives. Of course, they do not provide us with total control over our lives. On the contrary: narratives often deal with uncontrollable fate and tragic events. That which we cannot explain and control, we must narrate. However, even in those cases, or better: precisely in those cases, narratives may help us to live with fate and tragedies. That is how - in light of twentieth century discoveries, which have undermined the narrow Neo-Darwinism - we should look at our very nature: human nature transformed into humane nature.