John Dupré Gifford Lecture 2: Evolution
The most celebrated scientific idea in biology- evolution, of course is fundamentally based on a process of change. Dupré wants to expand this process of change through applying a processual perspective. What follows is a summary of the lecture and a short response from Ade, a PhD student studying at the University of Edinburgh.
The tree of life can reduce all species to one common denominator and also shows where species evolve and break off (end when extinct). This continual process is most easily mapped in sexual species, where lineages change to reflect difference in properties over time. But this does not help us map hybridity, where closely related species have much gene flow between them. Where this is the case why do we consider these two related species as distinct rather than one?
The promiscuous lateral gene transfer in some bacteria problematizes this question. Being able to trace the complete cell-line ancestry of a cell will not tell you about all its genetic ancestry. Additionally, as they are asexual, tracing its lineage is much more arbitrary- any cell could claim to be the founder of a new clad, and many part of many. Process ontology does not find these matters problematic. There need not be stabilization in the lineage for there to be temporarily stabilized structures at the level of the cell.
However, if this process paradigm complicates the simple single species evolution idea, this begs the question of what actually evolves?
‘The answer is lineages, species or sequences of species. Evolution occurs when distribution of traits in a lineage at one time differs from the distribution at a later time.’
An example: the relationship between rabbits in Australia and their ancestors in Europe. Their continued isolation will enable them to diverge so much that they become different species, but for now they still can possibly reproduce- despite already having differences. At the present time therefore, we can say this species is an evolving lineage, but the lineage is not a set, singular path Another example might be a river that splits into district streams- they may rejoin and be once again a single river, or they might take their own paths to sea and stay separate.
Ernst Mayr, another leading figure in 20th century evolutionary biology, provided the most widely accepted definition of the species. According to Mayr a species is a group of organisms connected to one another and isolated from other organisms by sexual relations and thus gene flow. He did not classify microbes as species (avoiding this particular exception to his rule). Species are the lowest level of biological classification (before we get to subspecies, races etc). The idea of a species is used for describing evolution or for classification. Every organism should, ideally, belong to a classificatory species; many will not be part of a coherent lineage.
Another part of the explanation as to the stability of a biological lineage is the ability to exhibit some kind of internal organisation to justify this being an individual process rather than a disconnected set of events. Dupré poses that the importance of stabilizing selection tends to be underappreciated. Thinking of it as creative is more exciting, or concentrating on things overlooks the significant process that led it there- allowed it to remain in the limits of its conditions of existence.
imagine a world in which survival was always purely a matter of chance. Individual lineages would gradually drift away from their starting condition, so that even if, somehow, we started with a reasonably homogeneous and coherent species, the homogeneity would decrease generation by generation.
Stabilizing selection is vital for continuing boundaries in species that sexually reproduce. Without it, variation within the species would inevitably increase, sexual compatibility would decline, and sexual species would eventually become extinct. In compatibility terms, mating mechanisms, colours in fish, songs of birds for instance attract a mate.
These mechanisms do not guarantee the avoidance of hybridity. Gene flow in oak trees are excessive but they still retain morphological distinctness, showing the relationship between natural selection and the homogenizing effects of gene flow. The earth worm, used by Charles Darwin, which evolved from an aquatic ancestor and never truly adapted to land life, flourishes by maintaining the moisture level in the soul. In return, this is beneficial for the larger eco-system, and shows the connectedness between the worm and the environmental to which is became attuned to.
The construction of complex structures over many generations- such as presented by beavers or humans is a quite rare accomplishment. The most extreme move along this dimension is the evolution of sociality. The peak is in insects or humans who have developed complex divisions of labour. Sociability also effects evolvability.
Enthusiasm for the overriding importance of natural selection has tended to draw attention away from an essential task in understanding evolution, where do evolutionary changes come from?
Of most interest to orthodox gene-centered evolutionary theory are small mutations and recombinations. Changes in architectural genes can result in major morphological effects. Epigenetic changes to the genome may be inherited or have behavioural effects that lead to their reconstruction through generations. Changes to behaviour may also be learnt from offspring. This is called cultural evolution.
‘While epigenetic inheritance significantly extends the possibilities allowed by orthodox neo-Darwinism, sociality opens up entirely new pathways.’
Extending the idea of evolution beyond the simplistic understanding of changing frequencies of genes also us to take into consideration how parental care is a form of sociality, which has profound effects on the development of offspring. Cultural evolution also develops beyond the parental to the larger social structure (in humans and other species). This contrasts with Richard Dawkins’s thesis that genes are ‘selfish’ in the evolutionary quest, and results in a ‘passive’ kind of evolution regarding the larger network that we class as an individual.
Noting the distinction here of bacteria (including archaea), sociality or parental relations also do not seem to apply (this will be returned to in the lecture series). We can classify this difference as r-selected and k-selected species. A frog would be an r-selected species where it lays thousands of eggs which lack parental care and are seemingly only in a relationship with natural selection. K-selection see high-parental attention given to a limited number of produced offspring. Local concentration and co-operation continue from this relationship to the environment. Co-operation in species has been overshadowed by evolutionists’ concentration on competition.
Cooperation enables the transmission of information between unrelated individuals […] It may allow more effective care of offspring through recruitment of helpers, and it allows far more elaborate transgenerational ventures in niche construction. […] cooperation can be very effective in identifying, isolating and sanctioning individuals who attempt to advance their own interests over that of the social whole.
Humans and their livestock make up over 95% of the vertebrate animals on the planet, and for each human there are 2.5 million ants. These groups point to a decisive benefit of cooperation, the enabling of a division of labour. Dupré explains, how architects, builders, sound and lighting engineers, IT specialists, clothes makers, the designers, manufacturers and operators of the aircraft, the taxi driver and hotel hospitality team have allowed him to be in Edinburgh today. Alongside this, consider how these roles have dramatically changed in the lineage of the Gifford Lectureship series, where typewriters have been replaced by our team of bloggers.
Genetic bases for evolution in the case study of humans, have become far less important than social and culturally mediated processes of change. The impact of the mobile phone changing how we operate and converse with one another is a good example where it has transformed our experience of social space.
It is ironic in the light of this that an ideal of autonomous individuality has been so powerful in recent centuries. For there is surely no doubt that it is the evolved capacities of our species as such, not of individual organisms, that is our peculiar strength.’
Organisms and lineages, Dupré has stressed to show, are persistent processes that are highly interdependent. He will continue this thesis in the next lecture to demonstrate the entanglement of organisms through symbiosis in the living world and also through reproduction.
Response Ade Mursyidi
In his second lecture, Dupré started the discussion by highlighting a dualistic category of things and processes, blurring the boundary between the two, and challenging the simplistic idea we tend to hold about the nature of ‘things.’ As he addressed the issue of evolution, this idea is reminiscent of one of two prevailing zeitgeists during Darwin’s life: typology and/or immutability of organisms. The teleological way of thinking and insufficient explanatory power of describing biological complexity and its natural mechanism combined enabled this paradigm to stand unchallenged for centuries. The fact that evolutionary thinking has been haunting the minds of pre-Darwinian philosophers, both Western and Eastern, does nothing to resolve the question.
It was Darwin’s serial discoveries since the second half of the 19th century that not only undermined the paradigm but also brutally removed its epistemological bedrock i.e., essentialism, making it nearly impossible to imagine an ontological return afterward. By learning that individual species are part of a population that possesses peculiar evolving features, believing in an eternal essence embedded in every single natural kind is no longer defensible. I think Dupré’s thoughtful presentation should be read in this light, among others, to make sense of all his philosophical argumentations. There is no doubt that his pluralist ontology challenges any essentialist and unificationist interpretation of science (natural kinds) in general and biological systems (lineage and species) in particular. His most widely discussed and criticized book, The Disorder of Things: Metaphysical Foundations of the Disunity of Science, has thrown the deep-seated attempt by philosophers of science within the contemporary unity of science movement to build a positivistic account of things in vain. Do you think this is an intellectual tragedy or a historical necessity?
This background, I think, can also help us understand his temptation to Lamarckian evolution that he used to accentuate a broader conception of human evolution, highlighted in the last part of his lecture. For him, our greater interest in individual organisms rather than human social species for centuries is ironic as it leads us to gloss over our potential strength: cooperation (from which cultural evolution is developed? Unless nature and nurture are fairly addressed, this idea will simply reduce individual agency). Though seemingly a promising point to consider, this respondent struggles to see how this alone justifies human peculiarity. As a matter of evolutionary degree, not a kind, however large it is, humans are not an exception to a macro-evolutionary process.
For this matter, in addition to a structural change of environment as Dupré pointed out, Darwin’s appeal to earthworms in his book, The Formation of Vegetable Mould through the Action of Worms, is also no less significant in highlighting the mental capacities of such low-organized animals by observing their cultural habits. The way they seize and drag leaves into their holes both to supply food and to protect them from rainy floods by plugging up the mouth of their burrows with those leaves or other inorganic matter accordingly shows a degree of rationality. To argue against opposing hypotheses, he further conducted an experiment by replacing the leaves with new oddly-shaped ones and observed how they dealt with this new situation. Surprisingly, they managed to handle the situation easily, as relying simply on instinctive capacities is definitely unlikely. Upon the result, Darwin convincingly concluded that worm action, however strange it is, is driven by intelligence, not instinct, let alone trial and error.
In light of this discovery, human exceptionalism has been largely, if not entirely, rejected by contemporary biologists, unless by those who have failed to submit to Hume’s guillotine, which I highly believe Dupre, as an anti-essentialist, is one of them. In responding to a question from the audience in his previous lecture, he insisted that instead of being a beneficial resource, essentialism poses a threat to our campaign of recognizing the unrecognized, including the excluded, and demarginalizing the marginalized. Again, we can see how his philosophical vision informs, to a greater degree, his view on biological issues. Though seemingly inevitable, sometimes we need to take into account the criticisms of card-carrying scientists.
Dupré’s comfortableness with being a macro-evolutionist certainly piques our interest as an interdisciplinary audience to a broader understanding of evolution in his philosophical way. The best way to accomplish this is through a metaphysical lens, as the further you delve into scientific details, the more likely you are to push aside transcendental notions. If there is a philosophical value to be delivered in this agenda, that is precisely what the pluralist school stands for. Like him, I am simply curious and eager to develop these ideas, and am looking forward to seeing what other material he engages with as he develops this idea in his upcoming lectures through concentrating on the particularities of our human species.
 Notice that the philosophy of biology is later pioneered mostly by anti-essentialist philosophers, among whom Ernst Mayr and David Hull are Dupre’s favourite.
 Darwin remained doubtful about the advantage of ‘plugging up the mouth of their burrows’. It was in Patrick Lavelle and Alister V. Spain study (2001) where this purpose was stated clearly.
 Religious way of thinking perfectly illustrates this point.
 If science is to be considered among those things possessing an unconditional essence, I would say that this case is doubtful by having a look at recent cases of ideological infiltration in scientific enterprises.