Nature abhors a vacuum, however, and something has already come in to take the place of moral deliberation: legalistic thinking. When judging whether some act is acceptable or not, people increasingly consider their entitlements and liabilities, and the contracts - implicit or explicit - they have signed up to. Such a way of thinking corrodes our relations with others and our moral sense.
Take accidents. Led on by no-win, no-fee solicitors, we are encouraged to think about who might be legally responsible and sue them. Whether or not anyone is morally responsible becomes an irrelevant question: it is purely a matter of legal entitlement.
Consider how neighbours go to the council to resolve rows about hedges, rather than coming to agreement by themselves based on a sympathetic understanding of their mutual needs and desires.
We are increasingly resorting to a legalistic way of thinking about what were previously moral issues - because we have no other framework in which to think about them. But the solution cannot be a return to the moral authority of religion - there is too much diversity of belief for any such authority to hold sway, and most people, devout or otherwise, simply would not defer to religious authority anyway.
Like it or not, we must do more to strengthen secular ethics, not as a moral system but as procedure. In secular ethical debates, we rely not on authority but on the giving of reasons, which others can assess and accept or reject. This does not lead to endemic relativism or a free-for-all because when we reach conclusions, everyone has to abide by them. But no such decision is ever simply handed down from on high: all moral precepts have to be debated and defended.
Schools have a vital role to play in this. In the absence of a society-wide agreement on what morality rests on, the example schools set in their approach to ethics is more important than ever before. I think they do a pretty good job, which is one reason why the moral decline predicted by the gloom-mongers has not yet come to be.
Yet schools can unwittingly reinforce the legalistic turn, if they are not careful. It is easy to talk up the extent to which good behaviour is a contract between members of the school community. Take the dual emphasis on rights and responsibility, for example. On the one hand, it is good for pupils to learn that they have obligations as well as entitlements, duties as well as rights. But such ways of thinking can be taken too far, so that children end up believing that all good behaviour is the quid pro quo for some other reward. School charters and behaviour contracts can have a similar effect.
This can be avoided if the school is a community whose principles are openly debated and defended. Such an environment reflects the reality of moral life in that there is no one master reason to be good, but lots of different ones.
Empathy, for example, allows us to see that causing people upset and misery is a bad thing in and of itself, and should be avoided by any decent person. There is also the question of what sort of people we wish to become. Cheats and bullies are unpleasant people, so who would want to become one of them?
This may not provide the rigid clarity some seek, but it is the best preparation for a world where the only clear rules are legal ones, and where morality is a complex matter, whether we like it or not.
'Complaint', Julian Baggini's latest book, is published by Profile
Julian Baggini, Editor of The Philosophers' Magazine.