Mill’s “Proof” of the Principle of Utility
Here is a possible reconstruction of the Mill’s proof:
1. The sole evidence it is possible to produce that anything is desirable is that people
actually desire it. (paragraph 3)
2. Each person desires his own happiness. (paragraph 3) Therefore,
3. Each person’s happiness is a good to that person. (paragraph 3) Therefore,
4. The general happiness is a good to the aggregate of all persons. (paragraph 3) {This
concludes the first part of the proof.}
5. Each person desires nothing which is not either a part of his happiness or a means of his
happiness. (paragraph 9, argued throughout paragraphs 5 – 10) Therefore,
6. Nothing is good to each person but insofar as it is either a part of his happiness or a
means of his happiness. (paragraph 11) Therefore,
7. Nothing is a good to the aggregate of all persons but insofar as it is either a part of the
general happiness or a means of the general happiness. {This concludes the second part
of the part.} Therefore, (from 4 and 7)
8. The general happiness is desirable, and the only thing desirable as an end, all other
things being only desirable as a means to that end. (paragraph 2) Therefore,
9. The promotion of happiness is the test by which to judge of all human conduct; from
whence it necessary follows that it must be the criterion of morality, since a part is
included in the whole. (paragraph 9)
There have been traditionally three parts of this proof that raise serious questions. They are:
1. The first premise, which asserts that desire is the sole evidence of desirability. Consider
what grounds Mill has for supporting this claim. Do you think the claim is acceptable?
2. Premise five has been questioned. Mill claims that we desire nothing other than
pleasure as an ultimate end. Are there other things we desire?
3. The connection between premises three and four and six and seven has also been
questioned. Relevant in this case is a common fallacy: the fallacy of composition, which
states that it is fallacious to attribute a characteristic of a member of each group to the
group as a whole. Does Mill commit this fallacy?
Think about these issues as you make your way through Chapter IV and consider what evidence
Mill cites for the key claims in his proof. Consider as well possible objections and what Mill
might say in reply to these objections.