From an atheist's perspective, goodness has become an awkward and dispiriting concept. Around the "good person", there hover a host of paradoxically negative associations: of piety, solemnity, bloodlessness and sexual renunciation, as if goodness were something one would try to be only when other more difficult but more fulfilling avenues had been exhausted. One thinks of melancholy moments of childhood, when one had to follow arbitrary school rules, write thank you letters for unwanted gifts and do community service.

Being good has come to feel dishonest. The great psychologists of the modern age, from La Bruyère to Freud, have convincingly shown that there are no intrinsically benevolent patterns of behaviour. Egoism and aggression are understood to lie at the heart of our personalities and never more so than in individuals who attempt to cover them up with unusual displays of virtue. The nun, the parish priest, the self-sacrificing politician; we have been trained to sense fouler impulses behind their gentle deeds. What looks like goodness must involve either obedience or perverted forms of egoism (the biographers can be expected to unearth the details in due course). Self-interested motives are glued to the underside of every apparently benevolent act. Probe hard enough at kindness, concern or pity and the clear-headed psychologist will soon come up against the fundamental bedrocks of character: envy, malice and fear. To be optimistic about the human condition is to appear sentimental, credulous and not a little simple-minded.

There is another reason to be suspicious of goodness, centring on insoluble doubts as to what the concept actually involves. After centuries of dogmatic certainty, we live in an era of militant doubt about ethical claims. None seem able to stand up to the quasi-scientific standards of proof that we demand of them – so that suggestions have been downgraded from the status of objective truths to that of simple prejudices. The sensitive, open-minded sections of society recognise all judgments to be culturally and contextually specific and therefore incapable of elevation to the rank of general truths.

A terror of old-fashioned moralism has driven all talk of morality out of the public sphere. Who would now dare to suggest how our neighbours should be judged in the vast domain we term private life? In flight from dogmatism, we stand transfixed by the dangers of moral convictions. A democratic spirit has served to generate scepticism about authority and hierarchy in every sphere. Judgments about values tremble before the incensed question of who one person could ever be to tell another how to live. Those who profess to have answers are ridiculed in a tone adopted by furious adolescents when probing at the assumptions of their parents. In the political arena, there is no faster way to insult opponents than to accuse them of trying to undertake the impossible task of improving the ethical basis of society. They can reliably be charged with believing in that most odious concept of modern secular politics, a nanny state.

We are familiar with our desires to become happy, successful and wealthy; it would sound peculiar and repellently high-minded to confess to any comparable ambition to become good.

There is a well-known argument, for which 20th-century history holds no shortage of evidence, which proposes that once God dies, anything becomes possible.

The thesis centres around issues of knowledge on the one hand and motivation on the other. It doubts how we can possibly know what is right and wrong without God to inform us. And it asks how – even if we do arrive at principles – we can ever be motivated to honour them without the forceful external encouragement provided by the spectres of heaven and hell.

Such reservations may have a superficial logic to them, but they are more vulnerable than they at first appear. To say that without God, we must surrender attachments to good and evil reveals a debt to the very religious mindset which the argument purports to question, for only if we had truly once believed that God existed – and that the foundations for morality were hence in their essence supernatural – would the recognition of God's non-existence force us to surrender moral principles.

Yet if we assume from the outset that it was of course humans who made God up, then the line rapidly collapses into a tautology, for why should anything have become possible simply because humans came to recognise that they were the authors of the very rules that they had once placed into the mouths of supernatural beings?

For the religious, moral codes exist because God offered them to us – and because they are true. For the secularist however, the origins of ethics are best accounted for in the most prosaic, cautionary and pragmatic terms which, while lacking any grandeur, at least have the habit of sounding convincing to hardened cynics. The codes exist because we made them up – and we did so as an answer to one the most hazardous problems of social existence: man's aggression against man. Religious morals were created as attempts to control our tendencies towards violence, vindictiveness, spite, rivalry, prejudice and infidelity – which would destroy society if left unchecked.

The answer to Machiavellians who relish in describing our insatiable selfishness is hence equivocal. We are of course motivated by our own advantage, but this necessarily includes that of the community at large. Whatever individualists might propose, effective capitalism does not last long without a strong ethical backbone. Self-interest therefore pushes us to appreciate the benefits of acting kindly, along with the exquisite sensations that come from reducing the suffering of others, besides which more straightforwardly selfish pleasures pale into insignificance (it has always been an especially perverse philosophical legacy to suggest that behaviour can only be considered good if it delivers no satisfaction whatsoever to the agent who performs it – a line which at its most absurd sees no difference in moral value between the actions of a criminal and of an aid worker, because both have been "motivated" to act as they see fit).

The Judeo-Christian moral code was designed to foster what we would now call "good relationships". We may not consciously want to become good, but we tend to perceive well enough why we would want to improve our talent at creating harmonious connections with children, parents, lovers, colleagues and fellow citizens – and are usually accorded a persuasive taste of the bitter consequences of failure by the time we reach adulthood.

Our religious codes are our cautionary rules, projected into the sky and reflected back to earth in disembodied and majestic forms. Forceful injunctions to be sympathetic, patient and just reflect our knowledge of what will draw our societies back from fragmentation and self-destruction. So vital are these injunctions that we did not for a long time dare to admit that we had even formulated them, lest this would allow them to be questioned and handled irreverently. We had to pretend that morality came from elsewhere to insulate it from our prevarications and our frailties.

Defenders of liberal neutrality and critics of the nanny state are apt to respond to the prospect of such a society with horror, pointing out how severely it would diminish that most cardinal of political goods, freedom. For many centuries, the word rightly generated immediate reverence. When monarchical governments demanded complete obedience to their corrupt authority and when individuals were harangued by repressive, misguided traditional religious forces, there could have been no more essential priority for political theorists than to question power, to deem authority inherently dangerous and to challenge attempts to dictate ethical behaviour from on high.

But one wonders whether the idea of freedom still always deserves the deference we are prepared to grant it; whether the word might not in truth be a historical anomaly which we should learn to nuance and adapt to our own circumstances. We might ask whether for developed societies, a lack of freedom remains the principal problem of communal life. In the chaos of the liberal free-market, we tend to lack not so much freedom, as the chance to use it well. We lack guidance, self-understanding, self-control, direction. Being left alone to ruin our lives as we please is not a liberty worth revering. Libertarians imply that external suggestions of how to behave must always strike us as unwelcome curtailments of our well-formulated plans. The external voice is – in this account – an inherently intrusive, undesirable one, impeding on the deliberations of rational, mature free agents.

However, unlike those unfeasibly self-contained, sane and reasonable grown-ups that we are assumed to be by liberal politicians, most of us are still disturbed children not beyond the tutelage of a wise nanny. We may in many situations long to be encouraged to behave as we would hope to, but don't manage, under the pressure of our working lives and the claustrophobia of our relationships. We may want outsiders who can help us to stay close to the commitments we revere but lose sight of. We may benefit from having witnesses, like house guests, who can shame us away from indulging our anger, narcissism, sadism, envy, laziness or despair.

Freedom worthy of its illustrious associations should not mean being left alone to destroy ourselves. It should be compatible with being admonished, guided and even on rare occasions restricted – and so helped to become who we hope to be.

• Read the Citizens Ethics pamphlet in full here