In Defense Of John Stuart Mill's Argument

John Stuart Mill was an advocate of utilitarianism, which is a normative moral theory that holds that the right action is the one that maximizes utility. His justification of utilitarianism is found in his proof of the “principle of utility”, which states that happiness is desirable, and the only thing desirable as an end. Basically, utilitarianism is proven true if the principle of utility is proven true. Mill poses the question “Can the principle of utility be proved?” and begins formulating his proof by asking what conditions it should fulfill in order to make its claims believable. I will reformulate Mill’s proof on the principle of utility as a deductive argument. Next, I will split the proof into its two basic claims and then present

Happiness is good/desirable.
2. Happiness is the only thing that is good/desirable as an end.
3. Therefore, utilitarianism is proven true.
The argument leading to the conclusion (1) can be presented as follows:

Premise 1a: The sole evidence required to show that something is desirable is that people desire it.
Premise 1b: Happiness is desired.
Conclusion 1: Therefore, we have the evidence required to show that happiness is desirable.

So far, Mill has come to the conclusion that happiness is desirable and it is a criterion for morality. However, he says that the previous argument is not sufficient to reach the conclusion that happiness is the sole criterion for morality. The argument leading to this conclusion (3) can be presented as follows:

Premise 2a: In order to show that happiness is the only thing that is desirable as end, it is required to show that nothing else is desired as an end.
Premise 2b: That which is desired is desired as a means to pleasure and becomes a part of happiness.
Conclusion 2: Therefore, happiness is the only thing desirable as an

West states that Mill has been accused of the “fallacy of equivocation”, which occurs when a key term in an argument in used ambiguously. In this case, West states that Mill has used the term desirable ambiguously because Mill confuses between desirable meaning “capable of being desired” and desirable meaning “worthy of being desired”. West counters this argument by stating that Mill may have been misinterpreted, since Mill does actually make a distinction between matters of fact, in the case of sound being audible, and matters of conduct, in the case of desire. Mill states that evidence for both matters of fact and matters of conduct must come from human experiences. In the case of matters of fact, evidence comes from sensory information. On the other hand, evidence for matters of conduct come from appetitive information (i.e. what we desire). He appeals to this evidence to show that happiness is