Opinions of octopus intelligence consequently vary within the scientific community. A fundamental precept of animal psychology, coined by the 19th-century British psychologist C Lloyd Morgan, says no behaviour should be attributed to a sophisticated internal process if it can be explained by a simpler one.
That is indicative of a general preference for simplicity of hypotheses in science, says Godfrey-Smith, that as a philosopher he is not convinced by. But scientific research across the board has become more outcome-driven as a result of the cycle of funding and publishing, and he is in the privileged position of being able to ask open-ended questions.
“That’s a great luxury, to be able to roam around year after year, putting pieces together very slowly.”
That process, set in motion by his chance encounter with a cuttlefish a decade ago, is ongoing. Now back based in Australia, lecturing at the University of Sydney, Godfrey-Smith says his study of cephalopods is increasingly influencing his professional life (and his personal one: Arrival, the 2016 film about first contact with “cephalopod-esque” aliens, was a “good, inventive film”, he says, though the invaders “were a bit more like jellyfish”).
When philosophers ponder the mind-body problem, none poses quite such a challenge as that of the octopus’s, and the study of cephalopods gives some clues to questions about the origins of our own consciousness.
Our last common ancestor existed 600m years ago and was thought to resemble a flattened worm, perhaps only millimetres long. Yet somewhere along the line, cephalopods developed high-resolution, camera eyes – as did we, entirely independently.
“A camera eye, with a lens that focuses an image on a retina – we’ve got it, they’ve got it, and that’s it,” says Godfrey-Smith. That it was “arrived at twice” in such vastly different animals gives pause for thought about the process of evolution, as does their inexplicably short life spans: most species of cephalopods live only about one to two years.
“When I learned that, I was just amazed – it was such a surprise,” says Godfrey-Smith, somewhat sadly. “I’d just gotten to know the animals. I thought, ‘I’ll be visiting these guys for ages.’ Then I thought, ‘No, I won’t, they’ll be dead in a few months.’
It’s perhaps the biggest paradox presented by an animal that has no shortage of contradictions: “A really big brain and a really short life.” From an evolutionary perspective, Godfrey-Smith explains, it does not give a good return on investment.
“It’s a bit like spending a vast amount of money to do a PhD, and then you’ve got two years to make use of it ... the accounting is really weird.”
One possibility is that an octopus’s brain needs to be powerful just to preside over such an unwieldy form, in the same way that a computer would need a state-of-the-art processor to perform a large volume of complex tasks.
“I mean, the body is so hard to control, with eight arms and every possible inch an elbow.” But that explanation doesn’t account for the flair, even playfulness with which they apply it.
“They behave smartly, they do all these novel, inventive things – that line of reasoning doesn’t resolve things, by any stretch,” says Godfrey-Smith. “There’s still a somewhat mysterious element there.”
- Other Minds: The Octopus and the Evolution of Intelligent Life is published by William Collins. To order a copy for £17 (RRP £20) go to bookshop.theguardian.com or call 0330 333 6846. Free UK p&p over £10, online orders only. Phone orders min p&p of £1.99. It is out through Harper Collins in Australia.