Here's part of the interview:
Editors: Frances Kamm once said...that utilitarians who believe in very demanding duties to aid and that not aiding is the same as harming, but nevertheless don’t live up to these demands, don’t really believe their own arguments....She concludes that ‘either something is wrong with that theory, or there is something wrong with its proponents’. What do you think about this argument? Why haven’t you given a kidney to someone who needs it now? You have two and you only need one. They have none that are working – it would make a huge difference to their life at very little cost to you.This response raises several questions, but I'll focus on just one. Singer believes it's wrong not to give the kidney and he feels bad, he feels guilty, about not doing so, yet why should he? In what sense is his violation of utilitarian principles morally wrong?
Peter Singer: I’m not sure that the cost to me of donating a kidney would be “very little” but I agree that it would harm me much less than it would benefit someone who is on dialysis. I also agree that for that reason my failure to donate a kidney is not ethically defensible.... Donating a kidney does involve a small risk of serious complications. Zell Kravinsky suggests that the risk is 1 in 4000.
I don’t think I’m weak-willed, but I do give greater weight to my own interests, and to those of my family and others close to me, than I should. Most people do that, in fact they do it to a greater extent than I do (because they do not give as much money to good causes as I do). That fact makes me feel less bad about my failure to give a kidney than I otherwise would. But I know that I am not doing what I ought to do.
Indeed, why is utilitarianism morally superior to the egoism to which he admits to succumbing?
To put it differently, if Singer chooses to be a utilitarian and donate the kidney while someone else chooses to be an egoist and keep his kidneys, why is either one right or wrong? Given Singer's naturalism, what does it even mean to say that someone is morally wrong anyway?
On naturalism there's no moral authority except one's own convictions and no accountability so in what way is keeping one's kidneys an offense to morality?
Elsewhere in the interview, Singer notes that his ethical thinking is based on the work of the great 19th century ethicist and utilitarian Henry Sidgwick and mentions that,
Sidgwick himself remained deeply troubled by his inability to demonstrate that egoism is irrational. That led him to speak of a “dualism of practical reason”—two opposing viewpoints, utilitarianism and egoism, seemed both to be rational.In other words, the choice between them is an arbitrary exercise of personal preference, although Singer doesn't agree with this because he believes evolution affords grounds for rejecting egoism. It's hard to see how this could be the case, however, since blind impersonal processes cannot impose moral duties.
Nor is it easy to see how acting against the trend of those processes can be morally wrong. How is one doing anything wrong if he chooses to act contrary to the way mutation and natural selection have shaped the human species? Why should he accept the ethical results of evolutionary history any more than we accept the physical limitations imposed on us by gravity when we go aloft in an airplane or hot air balloon?
The only reason we have for not putting our own interests ahead of the interests of others - as in the example of the kidney - and the only rational reason we would have for feeling guilt over our failure to consider the needs of others is if we believe that such failures are a transgression of an obligation imposed upon us by a transcendent personal moral authority.
Singer lacks such a belief and can thus give no compelling reason why anyone should be a utilitarian rather than an egoist. Indeed, egoism is a rational moral default position for anyone who embraces a naturalistic worldview.