‘Law’ says Plato in his dialogue The Statesman, ‘can never embrace in one prescription what is best and most right for everyone. The dissimilarities between men and between their actions and the fact that human affairs are pretty well always changing make it impossible for any skill whatever to lay down anything simple in connection with anything that will hold for all cases and at all times.’ Aristotle agrees. ‘It is the mark of an educated mind to aim at just so much precision of detail as the nature of the subject matter admits.’ In mathematics we expect exactitude; but in matters of conduct and what is advantageous, ‘nothing is fixed any more than in medicine’, and ‘the agents themselves must decide each case as it comes, just as must doctors and steersmen.’ The best thinkers of ancient Greece thought it obvious that we cannot achieve what is best for ourselves, cannot achieve the good for human beings, by following general rules.

Today it is sometimes said that there are certain general moral rules that bind without exception, rules that it is always wrong to break, whatever the circumstances. Is there a conflict between this and the ancient view?