Already in this series I have suggested that Bertrand Russell's critique of conventional religion is partly motivated by his reaction against repressive moralism. Although one might argue that this has nothing to do with the teaching of the gospels – in which we see Jesus's kindness to "sinners" and his recognition of the hypocrisy of those who judge others harshly – the Christian culture that Russell himself experienced certainly included moralistic attitudes. We get a sense of this when we consider how controversial Russell's own moral life was in the eyes of many of his contemporaries. The philosopher was married four times and had a long-term affair during his first marriage. In his 1929 book, Marriage and Morals, Russell argued for greater sexual freedom – and lost his job as a result.

Russell's progressive views about sexuality reflect his broader ethical outlook. He repeatedly advocated individual freedom in matters of personal morality, intellectual conviction and religious belief. He saw a threat to this freedom not only in Victorian morality and its 20th-century legacy, but also in modern bureaucracy. In a series of lectures on Authority and the Individual (1949), for example, Russell argues:

"In our own day, there has been too much of a tendency towards authority, and too little care for the preservation of initiative. Men in control of vast organisations have tended to be too abstract in their outlook, to forget what actual human beings are like, and to try to fit men to systems rather than systems to men."

Anyone who works for a "vast organisation" – a university, for example – knows all too well what Russell is talking about. But it is simplistic to blame those men (or women) who are "in control", as if they were creating and directing "systems" and are not themselves part of them. Of course, this only reinforces Russell's point that the machinery of modern culture produces a "lack of spontaneity".

On the question of personal morality, Russell puts forward an interesting argument that moral duty may call us to actions that are judged unethical in social terms.

"Duty to my neighbour, at any rate as my neighbour conceives it, may not be the whole of my duty," he says in Authority and the Individual. Russell invokes the concepts of God and conscience to explain this view, although he insists that it does not rest on theological belief:

"It is dangerous to allow politics and social duty to dominate too completely our conception of what constitutes individual excellence. What I am trying to convey … is in close harmony with Christian ethics. Socrates and the apostles laid it down that we ought to obey God rather than man, and the gospels enjoin love of God as emphatically as love of our neighbours. All great religious leaders, and also all great artists and intellectual discoverers, have shown a sense of moral compulsion to fulfill their creative impulses, and a sense of moral exaltation when they have done so. This emotion is the basis of what the gospels call duty to God and is separable from theological belief."

Russell is suggesting here that the idea of a relationship to God helps to free individuals from the social pressures of conventional morality. Indeed, the position he is outlining echoes what Kierkegaard famously called the "teleological suspension of the ethical" – a willingness to elevate individual conscience above social duty – which is displayed in the biblical story of Abraham's sacrifice of Isaac. The key objection to this Kierkegaardian view of Abraham – that it might be used to legitimate terrorist violence or delusional behaviour – apply to Russell's position too. It is true that Russell tries to protect himself from such extreme applications of his theory by stating that "society ought to allow me freedom to follow my convictions except when there are very powerful reasons for restraining me". But who is to adjudicate on these ' "reasons" if they are invoked by a society yet unacceptable to an individual's conscience?

To our ears, Russell's plea for individual liberty may sound like an amoral "anything goes" ethical stance. However, as well as invoking concepts of God and conscience, he also emphasises self-control. Russell regards sex as a natural human need, which is psychologically comparable with our desire for food and drink – and he argues in Marriage and Morals that over-indulging our sexual appetites is as unhealthy and inappropriate as gluttony:

"In regard to food we have restraints of three kinds, those of law, those of manners, and those of health. Restraints of a similar kind are essential where sex is concerned, but in this case they are more complex and involve much more self-control."

For Russell, self-control turns out to be the cure for both repressive moralism and immorality, for "fierce morality is generally a reaction against lustful emotions". We see this today in the coverage of scandals by certain newspapers, which manage to appeal to readers' prudish self-righteousness and desire for titillation at the same time. As Russell puts it: "Nothing but freedom will prevent undue obsession with sex, but even freedom will not have this effect unless it has become habitual and has been associated with a wise education."