Just because an angel is better than a stone, it does not follow that two angels are better than one angel and one stone. So said Aquinas (Summa contra Gentiles III, 71), and the sentiment was echoed by Leibniz. In section 118 of the Theodicy he wrote: "No substance is either absolutely precious or absolutely contemptible in the sight of God. It is certain that God attaches more importance to a man than to a lion, but I do not know (...) that we can bc sure that he prefers one man to an entire species of lions." Even Kant was bitten by this bug. In one of his pre-Critical works he was moved to say, à propos of lice, that even though they “may in our eyes be as worthless as you like, nevertheless it is of more consequence to Nature to conserve this species as a whole than to conserve a small number of members of a superior species." In these passages Aquinas, Leibniz, and Kant gave expression to a distinctive and interesting view about the value of animal species and animal populations. At its simplest, this is the view that there is a special value in the existence of animal species or in the existence of a wide variety of different animal species. But the view also goes deeper than this. An animal species, after all, is nothing over and above the individual animals which make it up, and the value which it contributes to the world must therefore be some function of the values contributed by those individual animals. At the deepest level, what the view expressed by Aquinas, Leibniz, and Kant holds is that the value which an individual animal contributes to thc world is not constant but varies with the number.. (shrink)

Thomas Hurka has recently proposed a utilitarian theory which would effect a compromise between Average and Total utilitarianism, the better to deal with issues in population ethics. This Compromise theory would incorporate the principle that the value which an extra happy person contributes to a possible world is a decreasing function of the total population of that world: that happy people are of diminishing marginal value. In spite of its initial plausibility I argue against this principle. I show that the (...) Compromise theory is actually no improvement over the two original versions of utilitarianism; in particular, it is subject to almost all the objections which are fatal to Average utilitarianism, and more besides. And I attempt to dispell the appearance that intuition supports the Compromise theory as against Total utilitarianism, by arguing that the latter's Repugnant Conclusion, when properly understood, is not intuitively unacceptable. Total utilitarianism remains a plausible ethical theory, while both the Average and the Compromise theories should be definitely rejected. (shrink)