This piece is part of my “Arguments” series. In this collection of posts, I examine and respond to some of the most common arguments used to defend the exploitation of animals or to criticise veganism.
These articles are not intended to be exhaustive treatments of each topic. Rather, they are designed as practical reference pieces, helping readers reflect on these arguments more carefully and respond to them in a thoughtful, informed way.
You can find other entries in this series here.
The Claim
The argument usually goes something like this: Humans have always eaten animals, so doing so cannot be wrong. The conclusion stated here is seldom actually said out loud, it is rather implied by using the fact that humans have always eaten animals as a justification for continuing to do so today.
It is true that humans have consumed animal products for much of our evolutionary history. Archaeological and anthropological evidence suggests that early humans incorporated meat into their diets tens of thousands of years ago, and that this likely played a role in survival and neurological development (1)(2)
However, acknowledging this history does not settle the ethical question of whether or not exploiting animals is justified today. The fact that a behaviour was once necessary does not mean that it remains justified when circumstances change.
The Short Answer
Humans have eaten animals for much of our history, often because it was necessary for survival in environments with limited food options. Today, for most people in industrialised societies, that necessity no longer exists. Extensive research shows that humans can be healthy on well-planned plant-based diets.
When a behaviour shifts from being essential to being optional, it becomes ethically open to questioning. What our ancestors did under conditions of scarcity does not automatically justify what we in consumer societies do under conditions of abundance. Many harmful practices have long histories, but longevity alone has never been a reliable guide to morality.
In modern societies, eating animals is usually a choice, rather than a requirement for survival. Ethical decisions should be based on our present knowledge and circumstances, not on past necessity.
The Detail
Eating Animals and Survival
For much of human history, access to reliable plant foods was limited. In many environments, hunting and fishing were essential for survival, and in among many indigenous communities, they still are. When an action is genuinely necessary, meaning that a person could not reasonably survive without it, it is not subject to the same moral evaluation as a freely chosen behaviour.
In those contexts, consuming animals was often a matter of necessity rather than preference. Today, for most people in industrialised societies, that situation no longer applies.
A substantial body of nutritional research shows that humans can be healthy on well-planned plant-based diets (3)(4). This means that for the majority of people in rich nations, eating animals is no longer required for survival. Eating animals is now a choice – that fact shifts matters ethically.
An ancient human hunting with basic tools in order to survive, or an indigenous subsistence hunter today, bear little resemblance to a modern consumer purchasing packaged meat in a supermarket. The moral context has changed completely. What was once necessary has become discretionary.
For this reason, modern recreational hunting and routine meat consumption cannot reasonably be defended by appealing to our evolutionary or cultural history.
Tradition Is Not a Moral Justification
Another version of this argument suggests that because humans have “always done” something, it must therefore be acceptable. This is a weak form of moral reasoning.
Human societies have practiced many harmful behaviours for thousands of years, including slavery, infanticide, violence against women, and extreme social hierarchies. Longevity alone has never been a good moral defence. The fact that a practice is old does not make it right.
We recognise this principle in most other areas of life. We seldom defend harmful traditions simply because they are traditional, yet when it comes to eating animals, this reasoning is often treated as sufficient. There is no good reason why it should be.
The relevant question is not what our ancestors did under conditions of scarcity and uncertainty. The relevant question is what we should do now, given our current knowledge, circumstances and access to alternatives.
Changing Knowledge and Changing Responsibilities
Today, we live in societies that offer abundant plant-based foods, detailed nutritional guidance, and accessible alternatives to animal products. We also know far more about animal sentience, environmental damage, and public health than any previous generation (5)(6). This knowledge changes our moral responsibilities.
When we understand the harm involved in a practice, and we know that viable alternatives exist, continuing that practice requires ethical justification. Historical precedent alone is not enough. Appealing to evolutionary history offers no meaningful ethical defence in this context.
Humans have always adapted their behaviour in response to new information and changing conditions. Moral progress has always involved questioning our existing habits.
Summary
Humans have eaten animals for much of our history, often out of necessity. Necessity is no longer the dominant context for most people today.
Modern meat consumption mostly takes place in societies with abundant alternatives, advanced technology, and widespread access to plant-based nutrition. In this setting, for most people, eating animals is largely a matter of preference, not survival.
The fact that something was once necessary does not mean it remains justified. Ethical decisions should be based on present realities, not past constraints. What matters is not what our ancestors had to do, it is what we choose to do now, when humane and sustainable alternatives are readily available.
Bibliography
- Smithsonian Magazine. (2012). How Eating Meat Made Us Human.
https://www.smithsonianmag.com/science-nature/how-eating-meat-made-us-human-130046796/ - National Geographic. (2011). Early Humans’ Big Brains Fueled by Meat.
https://www.nationalgeographic.com/science/article/early-humans-big-brains-fueled-by-meat - Academy of Nutrition and Dietetics. (2016). Position of the Academy of Nutrition and Dietetics: Vegetarian Diets. Journal of the Academy of Nutrition and Dietetics, 116(12), 1970–1980.
https://doi.org/10.1016/j.jand.2016.09.025 - British Dietetic Association. (2017). British Dietetic Association confirms vegan diets can support healthy living.
https://www.bda.uk.com/resource/vegetarian-vegan-plant-based-diet.html - Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES). (2019). Global Assessment Report on Biodiversity and Ecosystem Services.
https://ipbes.net/global-assessment - Food and Agriculture Organization of the United Nations (FAO). (2013). Tackling Climate Change Through Livestock.
https://www.fao.org/3/i3437e/i3437e.pdf
Support independent, research-based advocacy
Helping keep free, educational content online
