What's the source for the allusion of 'mere vessels of happiness'?

Question

Source: Benatar, David. Better Never to Have Been (2008 1 edn). pp. 36 Bottom - 37 Top.

  The judgements supported by the asymmetry of (3) and (4) are not universally shared. For example, positive utilitarians—who are interested not only in minimizing pain but also in maximizing pleasure—would tend to lament the absence of additional possible pleasure even if there were nobody deprived of that pleasure. On their view, there is a duty to bring people into existence if that would increase happiness. This is not to say that all positive utilitarians must reject the view about the asymmetry of (3) and (4). Positive utilitarians who are sympathetic to the asymmetry could draw a distinction between (i) promoting the happiness of people (that exist, or will exist independently of one’s choices) and (ii) increasing happiness by making people. This is the now famous distinction between (i) making people happy and (ii) making happy people. Positive utilitarians who draw this distinction could then,

consistent with positive utilitarianism, judge only (i) to be a requirement of morality. This is the preferable version of positive utilitarianism. Taking (ii) also to be a requirement of morality mistakenly assumes that the value of happiness is primary and the value of persons is derivative from this. However, it is not the case that people are valuable because they add extra happiness. Instead extra happiness is valuable because it is good for people—because it makes people’s lives go better. To think otherwise is to think that people are mere means to the production of happiness. Or, to use another famous image, it is to treat persons as mere vessels of happiness. But unlike a mere vessel, which is indifferent to how much of a valued substance it contains, a person cares about how much happiness he has.

Answer 1

I don't know the source of the allusion. It might be one of these:

This appears in Chapter II of Tess of the D'Urbervilles:

Tess Durbeyfield at this time of her life was a mere vessel of emotion untinctured by experience.

And Confucius (on pp. 71 and 94 of the book linked here) is said to have said,

Tzŭ Kung asked, saying: What, Sir, is your opinion of me?—I would liken you, Tz‘ŭ, replied the Master, to a vessel limited in its function.—What sort of vessel? asked Tzŭ Kung.—A richly ornamented sacrificial vessel, was the reply.

and

The higher type of man is not like a vessel which is designed for some Special use.

In general "vessel" can mean a ship or boat, or a container for liquids. I suppose your quotation takes it in the latter sense.

Answer 2

I am not convinced that "mere vessels of happiness" is in fact a "famous image" as claimed by Benatar. If it were famous then I would expect to be able to find more instances of the image using tools like Google Book Search or Google Scholar, but I have been unable to do so.

The closest that I have been able to find is in Singer (1981):

But pure Classical Utilitarianism treats people as replaceable vessels containing quantities of happiness, so that it is all right to kill a person if one can replace her with another person who will be just as happy, and there are no side-effects.

But this is not the same image! Singer's objection is about treating people as replaceable vessels (that is, aggregation of utility does not take into account the separation of persons), but Benatar's objection is about treating people as mere vessels (that is, as means rather than ends).

So I would have to put [citation needed] on Benatar's claim.

Reference

• Peter Singer (1981). "Reply to Dr Harris". Analytic Philosophy 22:4, pp. 198–200.