Knowing that we can control our own behaviour makes it more likely that we will.

It is a mistake to assume that the law should always enforce morality.

Of course, infanticide needs to be strictly legally controlled and rare - but it should not be ruled out, any more than abortion.

If penicillin had been judged by its toxicity to guinea pigs, it might never have been used by man.

Of all the arguments against voluntary euthanasia, the most influential is the slippery slope: once we allow doctors to kill patients, we will not be able to limit the killing to those who want to die.

Once we ask why it should be that all human beings - including infants, the intellectually disabled, criminal psychopaths, Hitler, Stalin, and the rest - have some kind of dignity or worth that no elephant, pig, or chimpanzee can ever achieve, we see that this question is as difficult to answer as our original request for some relevant fact that justifies the inequality of humans and other animals.

That's a central part of philosophy, of ethics. What do I owe to strangers? What do I owe to my family? What is it to live a good life? Those are questions which we face as individuals.