Veganism & Morality
Perhaps the strongest argument for veganism, but also perhaps the least persuasive one is that animals are living sentient beings who deserve to not be abused, raped, tortured, and eventually brutally slaughtered for consumption.
Common arguments for continuing this practice often reduce to animals being inferior beings not worthy of moral consideration. However, is this really the case? Are animals merely mindless automata or are they sentient living feeling beings?
Luckily, this is a question which we can answer, but before we answer this question, we should consider who we will extend moral consideration too. If animals are living feeling beings is that sufficient to deserve moral consideration?
Generally, we seem to have consensus that humans deserve moral consideration whereas inanimate objects such are rocks do not deserve moral consideration. (There are some people who will assert that plants and inanimate objects deserve moral consideration as well which is an argument entirely consistent with veganism, but an argument I will not tackle in this essay).
But why do we consider humans to deserve moral consideration while not rocks? A reasonably common view is that humans deserve moral consideration because of their capacity for suffering. That is since we recognize that humans can suffer in various ways, and we generally find this suffering unpleasant, we should take care not to cause undue suffering.
If you accept this view on who deserves moral consideration, I will argue that animal agriculture, and by extension meat consumption, is deeply unethical, and causes a lot of undue suffering to sentient living feeling animals.
Are animals sentient feeling beings?
The absolute scientific consensus is that most animals, and all farm animals do experience positive and negative emotions such as happiness and sadness, as well as more complex emotions such as depression and stress. In fact, the emotional systems in mammals (and other animals) are so similar to that of humans that a good first order approximation to how animals would feel in a situation is how humans would feel in that situation. In fact, we can extend the same moral considerations to animals as we have for humans.
Does animal agriculture cause undue suffering to animals?
In order to determine if the animal agriculture industry is unethical we need to determine if it causes undue suffering to the animals in it using human emotions as a first order approximation of the animals' emotions.
Let us first consider meat industry where animals are ultimately slaughtered. Since we have discovered that animals deserve the same moral consideration as humans, it follows from our hesitation from killing innocent humans that we should not kill animals which already makes eating meat unethical.
However, it gets worse. Even a vegetarian diet won't save us.
Let's look at milk production for example. Like all mammals, cows only produce milk after having been pregnant. The cows become pregnant by being sexually assaulted and raped by the farmer through a process euphemistically called artificial insemination. As soon as the cow gives birth, the calf is forcefully removed from the mother which is a traumatic experience for both. The mother will call for its calf for days. Male calfs are used for meat production whereas female calfs are typically used for milk production. After the calf is forcefully removed from the mother, the mother ready to be milked. The mother is then milked by a machine while being contained in a space too small for her to move or turn around. This usually lasts for 10 months before the whole process is started over again. This doesn't even to go into the multiple mutilations cows often undergo.
The egg industry isn't much better. It's common knowledge that hens don't have the required space, and that their beaks are mutilated without pain relief. However, what is perhaps less known is that shortly after birth male chickens are separated and killed only hours before birth either in gas chambers or in big crushers. Some chicks survive the gas, and are then beaten to death some survive all that and are transported away severely injured suffering. After two years hens are deemed not profitable enough because egg production slows, and are killed either on the farm, or in slaughterhouses where their throats are cut and they're dumped into boiling water all while still conscious.
Similar stories of cruelty can be told for all vegetarian products making vegetarian diets as unethical as meat diets leaving only vegan diets left.
So it's clear that to avoid cruelty, we have to adopt a plant based diet. And since it's perfectly safe for us to eat vegan, we have established that we have a moral imperative to eat plant based to avoid needless cruelty.