Theories on Animals and Ethics

How would we define the issue of animals and ethics and the use of animals- whether in biomedical use, exhibition, or as pets? Does common sense play a role in this? Is it a philosophical issue or a moral debate? Is it a personal choice or a societal dilemma? These questions are not easily answered- we can only say that it is a deeply divided issue and a long-standing subject for debate.

Before we can go into the various philosophical theories, we have to ask: what is the moral status of animals? They seem to exist on the borderline of our moral status. Some individuals accord animals strong moral status, others deny them any moral status at all. Still others are in the middle. What place should animals have in an acceptable moral system? Examining the moral status of animals requires some measure of theorizing in an area of philosophy known as ethical theory (DeGrazia, 1996).

Indirect Theories

Indirect theories state that animals do not warrant our moral concern on their own, but they may warrant concern only as they relate to human beings.

Religious Theories/Worldview Theories

Some philosophers deny that animals warrant direct moral concern due to religious or theories of the nature of the world and the proper place of its inhabitants. Aristotle (384-322 B.C.E.) was one of the earliest and clearest to express this kind of view. He stated that there is a natural hierarchy to living beings. While plants, animals, and human beings are all capable of taking in nutrition and growing, only animals and human beings are capable of conscious experience. This means that plants, being inferior to animals and human beings, have the function of serving the needs of animals and human beings. Likewise, human beings are superior to animals because human beings have the capacity for using reason to guide their conduct, while animals lack this ability and must instead rely on instinct. Therefore, the function of animals is to serve the needs of human beings (Regan and Singer, 1989).

St. Thomas Aquinas (1225-1274) stated that beings that are rational and capable of determining their actions are the only beings that we should extend concern “for their own sakes” (Regan and Singer, 1989). He believed that, if a being cannot direct its action then others must do so, so these beings are merely instruments. Instruments exist for the people who use them, not for their own sake. Since animals cannot direct their actions for their own sake, they exist for people’s sake.

Remnants of this type of view exists in the concept of “the food chain” – a chain of higher and higher animals until you come to the “highest” animal of the chain (e.g., human beings). Since this type of behavior is “natural”, then it does not require any further moral justification.

Kantian Theories

Immanuel Kant (1724-1804) developed a moral theory which stated that autonomy is a necessary property to be the kind of being whose interests are to count directly in the moral assessment of actions. Morally permissible actions are those that could be willed by all rational individuals in the circumstances. Willing is very important. Both animals and humans have desires that can compel them to action but only humans are capable of standing back from their desires and choosing which course of action to take. Since animals lack this ability, they lack a will, and therefore are not autonomous. Without this, they have no intrinsic value.

Cartesian Theories

Cartesian theories state that animals deserve no direct concern because animals are not conscious, therefore they have no interests or well-being to take into consideration when considering the effects of our actions. Someone who holds this position might agree that if animals were conscious then we would be required to consider their interests to be directly relevant to the assessment of actions that affect them; however, since they lack a welfare, there is nothing to take directly into account when acting.

Rene Descartes (1596-1650) was one of the first individuals to deny that animals had consciousness. He was writing during the time when a mechanistic view of the natural world was replacing the Aristotelian conception of the world and believed that all of animal behavior could be explained in purely mechanistic terms. He preferred to explain animal behavior by relying on the simplest possible explanation of their behavior (Regan and Singer, 1989).

There are more recent proponents of this view. Peter Harrison recently argued that the Argument from Analogy, one of the most common arguments for the claim that animals are conscious, is hopelessly flawed (Harrison, 1991). This Argument from Analogy relies on the similarities between animals and human beings in order to support the claim that animals are conscious. Peter Carruthers is another individual who suggests that animals are not conscious. He notes that there is a difference between conscious and non-conscious experiences in that conscious experiences are available to higher order thoughts and animals do not have higher-order thoughts and therefore, they are not conscious (Carruthers, 1989).

Direct but Unequal Theories

In direct but unequal theories, people account moral status of animals but not on an equal basis- not in regard to species. They claim animals have a direct moral status because of the following argument:

1. If a being is sentient, then it has direct moral status.

2. (Most) animals are sentient.

3. Therefore, most animals have direct moral status.

The usual manner of justifying the claim that animals are not equal to human beings is to point out that only humans have some property and then argue that property is what confers full and equal moral status to human beings. However, lacking rights does not entail lacking direct moral status; although rights entail duties it does not follow that duties entail rights. So although animals may have no rights, we may still have duties to them. So to this, people have added that only human beings are rational, autonomous, and self-conscious, only human beings can act morally, and only human beings are part of a moral community.

Direct and Equal Theories


You cannot talk about utilitarian theory and not mention Peter Singer – who has been very influential in the animal rights field and the debate concerning animals and ethics. The publication of his landmark book Animal Liberation in 1975 sparked the beginning of a growing and increasingly powerful movement in both the United States and Europe.

Utilitarian theories are concerned with choosing the action that will bring about the greatest good for the greatest number of individuals. When making these calculations to determine whether or not an action is morally right, you sum up the total amount of good that will be the result of a particular action and compare it to the total amount of harm that it will cause. This gives rise to a few inherent flaws (e.g., if we view animals as sentient creatures capable of perceiving pain and pleasure, we have to include these factors when determining whether an action is morally permissible, these calculations seem to require us to have advance knowledge of an outcome of research which we do not know). Classical utilitarianism has been criticized because it fails to take into account the inherent rights and respect owed to individuals (human and other living species) when determining whether an action is morally right.

Singer gives the interests of animals the same weight as the interests of humans. He states that equality is a moral idea, not a simple assertion of fact: if possessing a higher degree of intelligence does not entitle one human being to use another for its own ends, how can it entitle human beings to exploit nonhuman beings? (Singer, 1985) He speaks about what he calls the “Principle of Equal Consideration of Interests” which he describes as follows: The essence of the Principle of Equal Consideration of Interests is that we give equal weight in our moral deliberations to the like interests of all those affected by our actions.” (Singer, 1993).

Animal Rights

Tom Regan is another individual who is influential in the animal rights movement. His influential work “The Case for Animal Rights” covers the topic of animals and ethics. Regan argues that animals have rights in just the same way that human beings do. He thinks it is a mistake to ground equal moral status on utilitarian grounds, as Singer does, but that they have the same moral status as human beings grounded on rights not utilitarian principles. He relies on a concept of inherent value – any being that is a alive has inherent value. Anything that has inherent value is a being towards which we must show respect. In order to show respect to such a being, we cannot use it merely as a means to our ends.


Carruthers, Peter. “Brute Experience,” The Journal of Philosophy, 86 (1989): 258-69.
DeGrazia, David. Taking Animals Seriously. (New York, NY: Cambridge University Press, 1996).
Harrison, Peter. “Do Animals Feel Pain?” Philosophy 66 (1991): 25-40.
Singer, Peter. The Animal Liberation Movement. (Nottingham, England: Old Hammond Press, 1985).
Singer, Peter. Practical Ethics, (Cambridge: Cambridge University Press, 1993).
Regan, T. and P. Singer, eds. Animal Rights and Human Obligations. (Englewood Cliffs, NJ: Prentice Hall, 1989).