How and why is it that a significant number of non-lunatics continue to believe in Christianity or Marxism? Firstly, the believers usually find some way of explaining away the standard objections. The Christian says that God does not always remove evil, or answer our prayers, for what may seem bad to us may ultimately be for the best. The Marxist may say that revolution has not occurred in the West because the workers have been ‘bought off’ by the concession of higher standards of living, and have not realized that their true interest is in the overthrow of capitalism. Disputes about the great metaphysical questions of determinism or free will, materialism or immortality, seem able to go on forever without dislodging any side from its position. To the doubts about the respective prescriptions, the believers can reply that the full regeneration of man is still to come, and that the terrible things in the history of Christianity or communism are due to perfection being not yet achieved. By thus explaining away difficulties in his theory and appealing to the future for vindication, the believer can maintain his belief with some show of plausibility. The theorists of Church and State become well practised at such justification of the ways of God, or of the Party.

Secondly, the believer can take the offensive against criticism, by attacking the motivations of the critic. The Christian can say that those who persist in raising intellectual objections to Christianity are being blinded by sin, that it is their own pride and unwillingness to receive the grace of God that prevents them from seeing the light. The Marxist can similarly say that those who will not recognize the truth of Marx’s analysis of history and society are being deluded by their ‘false consciousness,’ the ideas and attitudes which are due to their economic position: the capitalist mode of production naturally prevents those who benefit from it from consciously acknowledging the truth about their society. So in each case, a critic’s motivations can be analysed in terms of the theory he is criticizing, and the believer may therefore think he can dismiss the criticism as based on illusion.

(Leslie Stevenson, Seven Theories of Human Nature, 2d ed. [New York: Oxford University Press, 1987], 14-5)