I’ve been vegetarian for 4 to 5 years now. If someone ask why I’m vegetarian, I have a basic default response of “It’s better for (a) animals (b) the environment (and therefore other people), and (c) one’s health”. However, each of these points can be challenged. I will explain how a philosophical problem called the ‘Non-identity problem’ demonstrates that it is not obviously clear that as many people or animals actually benefit from vegetarianism as many vegetarians argue.
Point (c) is most easily challenged. Vegetarianism may well be healthier than the average Western diet. Excessive consumption of (especially red) meat may contribute to increased risk of various cancer and other diseases. However, similar health benefits could be obtained simply by significantly cutting down on meat consumption, rather than completely eliminating it.
The same argument applies to (b). Environmental benefits could be obtained from cutting down on meat consumption, rather than completely eliminating it. However, unlike with health, continued reductions in meat consumption should noticeably benefit the environment, so that completely eliminating meat consumption is the environmentally optimum position. This is because of (i) the vast amount of land and water required to farm meat which could have otherwise been left as rainforest or woodland or used to grow crops straight for human consumption, (ii) the large amounts of greenhouses gases produced (iii) the amount of effluent produced etc. Of course, one might feel we have a duty to protect the environment for its own sake, but I think generally people want to protect it for the sake of the sentient beings that require ecosystems to be protected: humans and other animals.
So, unless you think the environment should be protected for its own sake, the environmental benefits of vegetarianism should actually fall under (a), as being something that is better for animals (including human-animals). Some of these benefits are obvious. Reducing pollution will immediately benefit existing people who suffer from it. Reducing the amount of land used to grow crops to feed animals could allow for more crops to be grown and thus help reduce world hunger (though it should be noted that economic factors play an important part in this; it is not necessarily true that there is not already enough food, it’s just that it is too expensive for many poor people). Reducing the impact of climate change will benefit existent young people who are likely to suffer the worst consequences of it.
How about other benefits? Environmentally, cutting down on greenhouse gas emissions should benefit future individuals by reducing the impact of climate change. And not eating animals should benefit the animals that would otherwise have been born into factory farms and inflicted with pain and suffering in their slaughter. But these 2 claims have a problem. They are both making claims about future people and animals, rather than those who already exist.
In the case of the animals (let’s assume they’re chickens), that would have been born into a factory farm, how can we say that they have benefitted by not being brought into existence? And in the case of the future individuals who have benefitted from the reduced impact of climate change, how can we say that they have benefitted by being brought into existence? This point of this latter question may not be obvious. But think about it: every action that we do or do not do will ultimately affect who is brought into existence, by way of interacting with different people and changing their behaviour ever so slightly, and thus ultimately changing which egg or sperm is involved in creating a new person, and therefore result in a person with a different identity being born.
The issue is: how (for the people) can existence be considered better than non-existence, or (for the chickens), how can non-existence be considered better than existence? This is at the core of Derek Parfit’s non-identity problem, which considers whether an act can be moral or immoral, even if no individual benefits or is harmed by the act.
Let’s focus on the people. Assume we do nothing about climate change, and as a consequence in the year 2040 an individual called John is born. John has to cope with the serious consequences of climate change, which dramatically harm his well-being. Out of 10, John has a well-being of 2. So it seems that John’s well-being is harmed by climate change. But by preventing climate change, John wouldn’t have existed; perhaps his parents never met, or they had a child, Paul, at a different time formed from a different egg and sperm, and Paul had a well-being of 7. What is John’s well-being in this case? Nothing. This does not mean John has a well-being of zero out of ten. If our ‘well-being’ scale goes from -10 to +10, with the extremes representing intense suffering and intense pleasure then a zero would be in the middle. If the scale goes from 0-10, then zero would represent intense suffering. So someone who exists could have zero well-being. But John doesn’t exist. It makes no sense to rank his well-being on the scale, because his well-being is non-existent. Similarly, in the scenario where John does exist, it makes no sense to say his well-being is ‘better’ than his well-being if he doesn’t.
This argument applies to everyone who has not yet been born (or at least not yet been conceived) who is supposed to benefit from averting climate change. And it applies to animals who are supposed to benefit by not being eaten. But it seems that none of these people or animals will actually benefit.
Is there a way around this problem? The most obvious argument is to point out that even if no future individual benefits from vegetarianism, future generations clearly do. So rather than comparing John’s well-being with his non-existent self, you compare him to Paul. Even though no-one is harmed or benefitted by preventing climate change, if we do so, then Paul will exist. And his well-being is higher than John’s, and therefore it is better that he exists than John does, and therefore it is better to adopt a vegetarian diet to prevent climate change. Problem solved.
However… the way we have solved the problem, by looking at it from the perspective of generational, impersonal benefits, is an essentially utilitarian approach. Which comes with a whole bunch of its own major problems. And unless we are going to keep them as pets instead, it doesn’t say why we shouldn’t eat chickens.