The fish had realised that what they were seeing in the mirror was in fact themselves.
“Man, it may be said, is distinguished from the animal world, and in that way from nature altogether, by knowing himself as 'I',” wrote the philosopher Georg W F Hegel more than two centuries ago.
Hegel worked within the tradition of the ancient Greek philosopher Aristotle, who in turn has been credited with “inventing” biology, the scientific method and formal logic. A preoccupation for philosophers ever since - and for us mere mortals - has been trying to discover the fundamental difference between human beings, other animals and indeed the universe at large.
When I first read Hegel’s words in his almost incomprehensible Science of Logic I was really excited. Not because he had “discovered” the difference between us and animals but because the difference he posited was so specific that it allowed for a better understanding of the huge similarities between us and the rest of nature.
This was radical in his time. It directly contradicted the dominant philosophy of Rene Decartes who seemed to suggest that animals - indeed the entire universe - were little more than complex machines. They were entirely separate from us - “I think therefore I am” - and separated from each other. Their workings could be discovered through dissection. This was seen as the sensible, scientific view.
In my own lifetime, I remember my father once telling me that cats could ask two questions: can I eat it and can it eat me. He was not fond of cats. This assumption about other living animals was informed by the common sense of our time. Humans are uniquely intelligent: animals are pets - or meat.
Hegel’s logic provided for a much more generous appraisal of animals. They did not have the concept of 'I'. They did not experience subjectivity. They did not have self-consciousness. They could not differentiate between their experience of an object and what the object might be in the world other than that experience. It’s a very small - if significant - difference.
This suggests that Hegel knew animals to be sentient beings, that can have emotions. They have a kind of intelligence. They are in so many other ways exactly the same as us. This was a bold claim in 1812, almost half a century before Darwin’s Origin of the Species would cause uproar for daring to suggest that we humans had evolved from the animals.
But now scientific experiments are demonstrating that Hegel too exaggerated the difference between humans and other animals and had failed to comprehend the actual intellectual prowess of other species. Animals - or at least some animals - do have a clear sense of “I” and do clearly project their subjective will on the objects of nature that surround them.
Chris Packham, the naturalist and broadcaster, has brought a new series titled Chris Packham’s Animal Einsteins to the BBC which discusses the complex reality of animal intelligence and consciousness in a way that is compelling and accessible to philosophers and indeed everyone else.
The author and photographer takes some remarkable findings from the pristine pages of the peer reviewed scientific literature and makes them available to millions of people. And this includes proof that some animals do in fact have a concept of “I”. They have a theory of mind and, like us, set themselves apart from the rest of their world.
The most surprising - and for me important - example in the programme is the extraordinary story of the blue-streak cleaner wrasse, a small tropical reef fish. Packham references groundbreaking research by Masanori Kohda from Osaka City University in Japan, published in PLOS Biology.
He says on the programme: “When we look in the mirror and see a smudge on our faces we instinctively rub it off. That is because when we look in a mirror we know we are looking at ourselves. I am not looking at another human male - I am looking at Chris. And that is because I have passed the mirror test.
“Only a relatively unique guild of animals have done that. Dolphins, elephants, the great apes, magpies - and of course humans. Well, up until now that is. New research conducted in 2019 has shown that the beautiful little bluestreak cleaner wrasse has now also passed the mirror test - making it one of the very first species of fish to pass this benchmark of brain power.”
“After being marked with a coloured gel on their stomach, an area they could only see by looking in the mirror, the wrasse started scraping themselves at the bottom of the tank to remove the mark. The fish had realised that what they were seeing in the mirror was in fact themselves.” He adds: “Recognising there is a difference between oneself and others is known as theory of mind.”
Indeed the entire series tears down almost any claim that humans have a single, identifiable trait that would set them apart from the rest of nature - a species–differentia based on a physical or intellectual ability that no other animal can demonstrate.
We see that the new caledonian crow can invent, make and use tools with a degree of sophistication beyond that of a human child aged five. We see that whales have culture, with a new fishing technique being adopted by pods living across oceans. Meerkat parents use a multi-stage training programme - “scorpion school” - with pups. Starlings exhibit social learning. Bees can count. All this comes in the first programme.
But of course it is our fellow great apes that are most like us humans. Packham shows in a later episode how chimpanzees, bonobos and orangutans all build complex beds in the forest canopy. So we cannot even claim to be unique in our building ability.
Chimpanzee have complex language - with more than 70 specific gestures. Many of these are actually shared with bonobos - and many are easily interpreted by young human children. This suggests that a common ancestor to humans and the other apes evolved to use language. In fact 90 percent of a child's inherited gestures are shared with other apes.
Packham recalls how the primatologist Dr Jane Goodall first observed chimps using a stripped twig to fish for termites. This was the first evidence for European scientists that the ape was a toolmaker. Paleoanthropologist Louis Leakey on hearing the news famously stated: “We must redefine ‘tool’, redefine ‘man’ or accept chimpanzees as humans.”
We humans believe we are the most intelligent species, and yet contemporary science has manifestly failed to understand just how intelligent our fellow animals are. Is this a failing of human intellect itself? I think the delusion we have created to differentiate ourselves from the birds and the bees is emotional in origin. The implications of having smart, empathic, sentient animals all around is as painful as it is awe inspiring.
If we know animals to be just like us, what does this say about our humanity? How can we tin squid? What are the implications in terms of the meat industrial complex and the squalor, pain and death we impose on the billions of animals we eat? What does biodiversity collapse now mean - the fact we are responsible for a mass extinction of thinking as well as feeling animals?
There is a further complexity from our imperial and colonial past. Human beings living in a different geographical space, or with different levels of melatonin, were treated like animals. This involved a racist distortion being introduced to science with the claim that black and brown people were less intelligent than white people. The differentiation between all humans and all other animals played an important and necessary function in correcting injustice.
I don’t think it is a coincidence that Packham brings this programme to us soon after becoming a vegan. The programme will - and should - encourage younger people to consider what eating meat means, what stopping ecological collapse means, when we know that even a tiny bluestreak cleaner wrasse may have the concept of “I”, and perhaps too a concept of I want to live.
Brendan Montague is editor of The Ecologist.