Constraints and Animals: a consistency argument-Robert Nozick
Introduction to Philosophy
Evan Mowry

Nozick’s pure argument, in logical form, is thus.

A1: Situations with the opportunity to do [y] are morally significant.
A2: [y] with regards to one thing promotes [y] with regards to dissimilar things.
A3: [y] is unnecessary to one’s health/well being.

P(1): If I find myself in situation [x], then despite the fact that doing [y] is pleasing to me, it is wrong to do it.
P(2): I am in situation [z], which is relevantly similar to [x].
Therefore: It is wrong to do [y], in situation [z].

With this, he makes three assumptions that, if agreed to, enable his argument for vegetarianism to work. The three assumptions are illustrated below:

A1: Situations with the opportunity to hurt an animal are morally significant.
A2: Disregarding the moral significance of hurting an animal promotes disregard for moral significance with regards to other situations involving hurting other living beings.
A3: Hurting an animal is unnecessary to one’s health/well being.

Nozick then parallels brutalizing an animal with eating an animal. They are, at their core, very similar acts: killing is the same as butchering; only intent differs, and the result is always the same: the death of an animal (designated as morally significant). He can then substitute eating an animal for brutalizing an animal. He does this by utilizing his argument form used with the baseball bat example, as shown above, with the three questions (assumptions) detailed at the beginning of the argument.
Having substituted harm to animals with meat eating (through explanation of the necessary events that must occur in order for meat to be available to eat), Nozick has now applied the act of eating meat to a definition of a morally repugnant act, and can logically substitute it for [x] in his base argument, thereby “proving” that eating meat is wrong in a situation in which you could eat it.

P(1): If I have the opportunity to hurt an animal, then despite the fact that hurting an animal is pleasurable to me, it is wrong to do so.
P(2): Hurting an animal is a relevantly similar situation to eating meat.
Therefore: It is wrong to eat meat.

Nozick’s argument is interesting in that it requires an assumed, shared set of beliefs about animals’ moral significance, and the nutritional value of meat. This weakens the strength of his argument; his assumptions would presumably be very difficult to defend. However, he develops a fairly watertight argument for vegetarianism, which is a very hard determination to logically defend, due to its intensely moral nature.