According to the Bible, human ancestors were vegetarian. According to science, human ancestors were vegetarian. Famous vegetarian advocates include Pythagoras, Leonardo Da Vinci, the author of Frankenstein, Gandhi, Einstein and Dr. Spock (as well as Mr. Spock).
The claim that humans need to eat meat and or dairy for health and survival is easily disproven by the reality that large numbers of plant-eating humans exist–and always have.
If dairy consumption is natural, why would humans be the only species on the earth that needs to drink excretions from other mammals?
If humans are biologically meant to eat meat and dairy why is it that they can only do it with tools (excluding scavenging for bird eggs or insects)?
While some claim that they have a unique personal health situation that require they consume meat or dairy, the observable reality is that humans cannot exploit the animals that are routinely cite as a natural food source for humans—cattle-pigs-chickens–without tool assistance.
Plants? Humans can eat them without any tool assistance.
Real natural born carnivores and omnivores that rely on predation are born with what they require for hunting. Tool use by humans for hunting and meat consumption can also be used for gardening and killing other humans–a frequent occurrence–something real predators do not engage in by comparison. Real predators do not have hunting seasons and they never mistake another animal for their prey. Among tigers and lions, there is nothing to compare to a human who accidentally wounds themselves or another hunter with bullet or spear. You never hear about tigers falling on their claws and mortally injuring themselves. Real predators go after the weakest animals, while humans prefer to kill the strongest. Unlike fangs and claws, projectile weapons are inaccurate and crude: while a rabbit may escape a bobcat with slight injuries, the victim of a bullet or arrow can linger on for days and experience a slow miserable death that only humans can engineer.
Whatever humans may be, there are not natural predators (unless humans are included as their natural prey).
Meat consumption by humans is not a balance–humans spread out, cutting down forests for grazing land, depleting water resources for growing crops to feed the exploited animals, killing real natural born predator species like lions and wolves for daring to attack domesticated herds, and massacring wild herbivores who graze on land they have occupied since time immemorial.
Some believe that meat has a natural power, and yet the strongest land animals in Nature are all herbivores–elephants, gorillas, horses, bulls.
Or they arrogantly believe humans are “top of the food chain” or an “apex predator,” and yet such hierarchies are subjective and biased personal opinions–Nature cannot be shown to give out prizes to species designated as such. All organisms die one way or another and end up in the ground as food for insects. Where is the superiority? The fact that humans routinely exploit other humans is the best proof we have that this claim of superior standing is not supported by the evidence. One could even say a cannibal must be higher on the food chain than those that do not eat the flesh of other humans. It is common sense that the easiest earliest source of flesh for humans to consume would be the bodies of dead humans, and we know there have been cannibal tribes that eat dead relatives.
Then there is the claim that abstaining from animal products is more unethical than indulging, because of some calculation that crop harvesting leads to accidental animal deaths. The basic moral absurdity in this position is demonstrated by making the scenario a forked road where one side is obscured by fog and the other is clear but has several humans standing in view. According to the morality of the crop death theory, it is better to drive on and run over the people you can see, then either take the foggy road where you don’t know who you may hit or to get out and walk–the equivalent of less intensive agriculture. An interesting oversight of the meat and dairy proponents is that they are quick to declare we return to 19th agriculture practices for their diet, but do not seem to acknowledge the same options for a vegetarian one.
The wasting of plants and water to feed “livestock” animals that can be fed to humans is a very simple common sense argument against meat and dairy consumption. If you care about human rights you wouldn’t want to waste the vast amounts of water and crops that could feed humans.
If you care about deforestation in the Amazon to grow soy to feed animals for the meat industry, you would not support meat eating.
If you care about preventing epidemics—diseases that originated in nonhuman populations and spread to humans like measles, tuberculosis, smallpox, influenza or AIDS (believed to have originated from “bush meat” hunters), then you should not support meat eating.
Thanks to a human dietary choice, nonhuman animals are born to be raped, force-fed and/or starved, castrated, mutilated, branded, turned into cannibals (even when herbivores), living in filth without space to move, or sit, or stand up, or turn around, deprived of space, family, companionship, sunlight, fresh air, or the natural right to touch the earth. And thanks to human bio-engineering, even if some are spared the farm and slaughterhouse, they are cursed by selective breeding that will ensure they grow so large; their own legs will not support them. Even if you deny all the cruelty and assume the animals have blissful lives before they are slaughtered– they are born to die for choice, not need.
Those that claim the problem amounts to a few bad apples are making the same excuses as slavery apologists. Unnecessary violence and victimization can never be made just and fair.
The moral argument for meat eating usually rests on a fable–a bedtime story-that humans as a group have superior moral worth.
This belief is not examined closely—if it were it would be obvious that human superior moral worth is as much biased personal opinion as an argument to defend racial, gender, or religious supremacy.
The criteria cited to prove human supremacy include mind, intelligence, soul, creativity, Divine specialness, Evolutionary specialness, survival of the fittest, moral reciprocity, or an unspecified faculty X. They are all as much subjective personal opinion as the importance given to skin colour or gender or a particular interpretation of scripture. Nature does not confirm this alleged superiority through natural phenomenon like weather, gravity, earthquakes etc and the constant routine natural exploitation of humans by other humans.
Humans do not serve a stewardship function like worms or bees–the world would be fine without them. If the world lost worms and bees, life systems would collapse.
It is small wonder people have to claim an invisible mute deity or deities has ordained humans superior in moral value even though we have endless examples of humans slaughtering each other in the name of those same deities, due to differences of opinion on religious trivia—including diet.
Ultimately, a moral argument for vegetarianism rests on a version of the golden rule–if you want human rights, you must have nonhuman rights if for no other reason than to close a loophole that would allow humans to justify exploiting humans.
If you claim humans can justify the systemic exploitation of nonhumans based on biased personal opinion then another human can justify the systemic exploitation of humans using biased personal opinion since you cannot prove any of these opinions to be absolute, fair objective truth.
It is common sense that only humans can be shown to use moral codes and laws in an effort to control their behavior thus they are the only ones obligated to follow them, nonhumans benefit without needing to reciprocate out of fairness and consistency, since punishing them for being unable to follow human laws when you know they cannot would be like punishing a blind man for not reading warning signs or an armless man for not grabbing a drowning swimmer.
Moral perfection is impossible; you only do the best you can in any given situation. The failure to stop homicide or child abuse does not justify concentration camps, thus the failure to stop the accidental death of microbes or plants does not justify the construction and maintenance of meat and dairy farms.
Slavery and war are as ancient as common as meat and dairy consumption but there is a general consensus that such things are bad and should be discouraged. For moral consistency, human consumption of animal products is likewise unnecessary and indefensible.