For how long can we treat the suffering of animals as an inconvenient truth?

Scientific insight is a powerful thing, but will it ever override the human lust for health, prosperity and, saddest of all, convenience? This question entered my head as I read of the Labour party’s newly announced policies for animal welfare “informed and underpinned by the latest evidence on animal sentience”. Such an approach would lead to laudable bans on foie gras imports and nonsensical badger culling. But let’s be careful what we wish for: further down the line, it would also lead to some uncomfortable dilemmas. In fact, how we redraw our relationship with animals promises to be one of the dominant themes of the coming decades.

Those alert to animal sentience already find themselves in difficult situations. Richard Dawkins, for example, has declared: “We have no general reason to think that non-human animals feel pain less acutely than we do.” This, Dawkins says, should change our cultural habits. Practices such as branding cattle, castration without anaesthetic and bullfighting, for instance, “should be treated as morally equivalent to doing the same thing to human beings”.

Neuroscientist Christof Koch, who researches consciousness in all its forms, has expressed discomfort over the question of whether we should eat animals. “What right do I have to kill them if they’re not just automata but can actually sense and feel?” he asks. The philosopher David Chalmers feels much the same but has drawn an arbitrary distinction between simple and complex consciousnesses, allowing him to eat fish and chicken.

Such cognitive acrobatics are routine in this field. Exchanging views with an animal consciousness researcher, she admitted she found it difficult to eat animals that she knew were sentient. As a result, she said, she never ate any species she had studied. And, she added, she would never study cows.

There’s no escape via the “lower” animals, though. Plenty of research suggests that chickens are not unfeeling meat stores on two drumsticks. They suffer distress, even when they are not suffering themselves. Uncomfortable as it may be to learn this, chickens demonstrate empathy for one another. Studies of fish brains and behaviour suggest that intensive farming practices are almost certainly causing fish conscious distress. And then there are the cephalopods: the octopus, squid and cuttlefish. Their brains have the capacity to think, plan, reflect and learn and almost certainly feel, in the same way that humans do. Octopuses make this clear, showing intention and imagination when they carry shelters with them, build settlements, vary their hunting habits from day to day and escape from captivity when given the chance. Thanks to revelations such as these, while I still eat cows, sheep and pigs, I no longer eat octopus. It’s my own little cognitive dissonance; after all, I haven’t quite given up eating cuttlefish, even though I know about studies that show that they, like cats and dogs, dream when asleep. I have, unconsciously, drawn a line.

But here’s the real dilemma: how many inconvenient truths will we tolerate?

Take the inconvenience – to some – of a fox’s sentience. Although it is scientifically impossible to know what a fox feels when chased by a pack of hounds, our understanding of animal brains gives us reliable hints. We share millions of years of evolution with the fox and the basic brain responses rely on similar circuits and chemical flows. Being hunted by dogs is almost certainly as terrifying for a fox as it would be for us.

It goes further “down”, though. Experiments have shown that cockroaches and funnel-web spiders experience distress and suffering in certain situations. Is it then unethical to use invertebrates in experiments without considering how these creatures might be feeling? This seems like going too far, doesn’t it? To most of us, spiders and cockroaches are of significantly lower value than humans.

But we should remember that our relationship with these creatures, and all creatures, is a cultural one. Millennia of reliance on their protein and other assets, an instinct to avoid the dangers they might pose and an ignorance of their inner lives have inculcated a conviction that they don’t have the same worth or value as humans. Now that science is showing us the reality of what it’s like to be a factory chicken, an ostrich raised for steaks or a caged cockroach, can we overcome our conditioning and react appropriately?

Bioethicist David Mellor, who was influential in drafting New Zealand’s progressive animal welfare legislation, says our deepened scientific understanding of the animal experience means we should move away from giving the animals in our care mere “freedoms” from negative experience; we should, instead, be ensuring they enjoy lives that are “worth living”.

It will be difficult. While we have banned research on chimpanzees, we still indulge the cognitive dissonance that allows us to experiment on monkeys, despite what we know about these creatures. The scientific justification is one of “necessary evil”: the potential for medical advances outweighs the impact on the individual animals. But the value judgment is writ large: the same argument would hold no water if the individual animal in question were human.

Sadly, that has not always been true. We humans have a history of experimenting on our own kind if we can find a way to undermine people’s intrinsic humanity on the basis of race or mental capacity. Times change and perhaps they will change again. It is not impossible that, within a few decades, eating meat will carry the same stigma as smoking tobacco, or using cosmetics tested on animals, has begun to carry now.

There are some stern tests ahead, however. Which of us, for instance, would refuse a life-saving transplant just because the heart, though human, was grown in a pig? Raising genetically manipulated pigs containing human organs is becoming a real possibility, but will involve millions of animals that die just so humans can live.

Is that, in Mellor’s terms, a life worth living? Should we feel as uncomfortable about these pigs as we do about the humans cloned and raised for their organs in Kazuo Ishiguro’s novel Never Let Me Go? I think we should, but I’m not convinced that we do – or ever will.

Michael Brooks is the author of The Quantum Astrologer’s Handbook and co-host of the science and culture podcast Science(ish)