Since the war there has been a revival of interest in the idea of justice and its relation to law. The main contributions have come from the side of jurisprudence among which may be mentioned Sir Carleton Kemp Allen, Aspects of Justice (1958); Potter, The Quest of Justice (1951); Friedmann, Legal Theory (1944); Stone, Province and Function of Law (1947); Paton, Textbook of Jurisprudence (1946); Goodhart, English Law and the Moral Law (1953); H. L. Hart, The Concept of Law (1962); E. Dowrick, Justice According to English Common Lawyers (1961); there have also appeared English translations of important continental contributions, such as the translation by Campbell of Del Vecchio's Justice (1935); by C. D. Broad of Axel Hägerströms's Inquiries into the Nature of Law and Morals (1953) and the work by Alf Ross On Law and Justice (1958).

Throughout the history of philosophy there has been a sustained interest in the concepts of knowledge, truth and meaning; interest in the concepts of error, falsity and nonsense, on the other hand, has been intermittent and spasmodic. Error, for example, has suffered at the expense of knowledge to such an extent that sometimes its very existence has been denied, or it has been explained away as being merely the absence of or privation of knowledge; many theories of truth are so constructed that no place can be found for falsity, and theories about what constitutes making sense pay, on the whole, little heed to what constitutes nonsense. In this paper I hope to do something to redress the balance so far as error is concerned. My remarks are prompted by the hope that, just as we may best understand health through the study of disease, so a consideration of error or failure may throw light on knowledge or success. It is clearly not very informative to say of error, falsity and nonsense that they are merely the absence of knowledge, truth and sense; indeed it is just as laconic as a proposed medical definition of disease as the absence of health.

In recent years, political scientists have talked a great deal about the proper definition of their subject, and of how the ‘field’ of the political scientist is best distinguished from that of other social scientists. One proposal that is frequently made is that political science might quite properly be defined as the study of power, its forms, its sources, its distribution, its modes of exercise, its effects. The general justification for this proposal is, of course, that political activity itself appears to be connected very intimately with power: it is often said that political activity is a struggle for power; that constitutions and other political institutions are methods of defining and regularising the distribution and the exercise of power, and so on. Since there seems to be some sense in which one can say that, within the wider area of social life, the political field is that which has some special connection with power, it may seem plausible then to suggest that the study of politics focusses upon the study of power.

In a paper entitled ‘Saints and Heroes’1 Professor J. O. Urmson has criticised ‘the trichotomy of duties, indifferent actions, and wrongdoing’ (p. 215), commonly found in moral philosophy, on the ground that it fails to cover an important class of actions, of which saintly and heroic actions are ‘conspicuous” but by no means the only examples. I am inclined to think that this trichotomy is defensible, and that at least it deserves a much longer run for its money than Urmson gives it. The form in which he presents it, however, makes it more implausible than it need be and this is perhaps the main reason why he finds it so indefensible.