Wiring the Brain

“Cognition” is one of those terms that we use a lot, but which is actually rather hard to define. The question of what constitutes cognition looms large in debates about whether other organisms, besides humans, do it or have it. Most people are willing to grant that many animals are in some way cognitive, but what about simpler critters, like nematodes or jellyfish? Are they capable of cognition? For that matter, what about bacteria or plants? Can they cognize? How about artificial systems, like large language models? Does cognition require a nervous system? Does it necessarily involve “thinking”? Or some kind of “mental” activity? Once you start defining it in that rather circular fashion, you quickly realise we don’t have good definitions of “thinking” or “mental” either!   Is cognition just “what cognitive scientists study”? Or are they only studying a particular version of it – the kind of cognition we see in humans? Maybe there is a less anthropocentric way to define i...

A new paper just out in Nature , by Peter Visscher and colleagues (including bio-ethicist Julian Salvulescu) explores the idea of polygenic genome editing of human embryos to reduce the risk of common diseases. This is, to say the least, a controversial idea, and a decidedly fantastical one. The authors present the results of statistical modelling which suggests that editing a small number of risk variants in each embryo’s genome could dramatically reduce the risk of a number of common disorders. But there are good reasons (lots of them) to doubt the assumptions on which this modelling is based and to have serious concerns about possibly deleterious unintended consequences of such interventions. I co-wrote a commentary on the article with geneticist Shai Carmi and law professor and bio-ethicist Hank Greely, outlining some of the limitations of the modelling and our concerns over the dangers of the proposed approach. I’ll expand on those points here.   First, the development...