Rachell Powell on Evolutionary Convergence, Morality, and Mind | Mindscape 342

Unlike physics, which has universal laws allowing for broad predictions, biology possesses few, if any, contentful universal laws. The principle of natural selection, while universally applicable, is generic and doesn't predict specific outcomes or 'globally optimal traits,' making biological history inherently less predictable than physical phenomena.

The host and guest discuss how the Copernican principle holds up in physics (universality of laws, garden-variety solar system) but breaks down in biology. The principle of natural selection is described as an 'a priori truth' or 'mathematical model' lacking specific content, unable to predict what traits will evolve, as fitness depends entirely on local environments.

Steven Jay Gould's thought experiment posits that if the 'tape of life' were rewound and replayed, the outcomes would likely be vastly different. Early, 'highly determinative' genetic and developmental nodes lock in certain body plans, making subsequent changes difficult without disrupting the entire system. This highlights the unique, non-replicable nature of evolutionary trajectories.

Gould's argument is illustrated by the Cambrian explosion, where a diverse array of animal phyla arose rapidly. He questioned if vertebrates would have become dominant if the tape were replayed. The end-Cretaceous extinction is another example, where the contingent asteroid impact vacated niches, allowing mammals to diversify, which was not an 'inevitability'.

Convergent evolution, the independent development of similar biological forms or functions in different lineages, can be seen as nature's way of 'rerunning the tape' at smaller scales. These repetitions suggest underlying 'law-like necessity' that challenges the strong contingency thesis, providing data in the absence of extraterrestrial life forms.

The guest explains that evolutionists point to convergent evolution (e.g., different species developing sight, fish-like body shapes) as evidence against Gould's contingency. This phenomenon offers 'natural experimental replications' that indicate certain optimal solutions are repeatedly found by evolution.

While many cognitive abilities show convergence across species, human cumulative culture—the ability to retain and incrementally improve innovations across generations—is presented as a unique and highly contingent evolutionary development. This capacity, rather than individual intelligence, is the primary driver of human ecological impact and technological advancement.

The guest argues that humans were 'not that' (a cumulative cultural species) for 99% of their history, despite having the necessary biology. She suggests that humans are not inherently 'smarter' than dolphins but benefit from cumulative culture, which allows for building upon past innovations rather than reinventing them. This 'takes an enormous amount of time for some innovation to suddenly pop out'.

Social norms, defined as rules of conduct regulating behavior to stabilize cooperation, are not exclusive to humans. By adopting a 'multiply cognitively realizable' definition (i.e., achievable through different cognitive mechanisms), one can observe robust social normative structures, including 'law enforcement' by subordinates, in social insects, challenging anthropocentric views of morality.

The guest argues that social insects provide the 'best case' for social norms outside humans, exhibiting 'institutionalized form of norm enforcement' by subordinates, which even chimpanzees lack. This functional convergence highlights that the underlying purpose of stabilizing cooperation can be achieved through diverse biological and cognitive pathways.