It is a chilly Monday in late March, just less than a year ago. I am at Princeton University. My host is Prof. Peter Singer, often called -- and not just by his book publicist -- the most influential philosopher of our time. He is the man who wants me dead. No, that's not at all fair. He wants to legalize the killing of certain babies who might come to be like me if allowed to live. He also says he believes that it should be lawful under some circumstances to kill, at any age, individuals with cognitive impairments so severe that he doesn't consider them ''persons.'' What does it take to be a person? Awareness of your own existence in time. The capacity to harbor preferences as to the future, including the preference for continuing to live.

At this stage of my life, he says, I am a person. However, as an infant, I wasn't. I, like all humans, was born without self-awareness. And eventually, assuming my brain finally gets so fried that I fall into that wonderland where self and other and present and past and future blur into one boundless, formless all or nothing, then I'll lose my personhood and therefore my right to life. Then, he says, my family and doctors might put me out of my misery, or out of my bliss or oblivion, and no one count it murder.