At an earlier period he had been brought under the influence of the writings of Bentham, and resolved to work out that philosopher's utilitarian principles. Correspondence led to personal acquaintance. A strong attachment grew up between the two men, and at Bentham's request Thompson visited him in London, and lived with him for some years. Thompson was also an enthusiastic supporter of Robert Owen, whose co-operative system he believed to be the means of realising the conception of 'the greatest happiness of the greatest number.' At the same time Thompson closely studied Godwin's 'Political Justice.'
In 1824 Thompson held a public discussion at Cork with one who had acquired a considerable local reputation for ' his skill in the controversies of political economy.' In the result Thompson published in the same year his chief work, 'An Inquiry into the Principles of the Distribution of Wealth most conducive to Human Happiness.' A second edition appeared in 1850, and a third in 1869, edited by William Pare [q. v.] Thompson starts with the assumption that all wealth is the product of labour, which is the sole measure as well as the characteristic distinction of wealth. The three principles he proceeds to lay down are : first, all labour ought to be free and voluntary as to its direction and continuance ; secondly, all the products of labour ought to be secured to the producers of them ; thirdly, all exchanges of these products ought to be free and voluntary.
In working out his theory of the right to the whole produce of labour Thompson does not lose sight of the doctrine of the right to subsistence on the part of the young or of the incapacitated. He did not clearly see the logical difference between the right to the whole produce of labour and the right to subsistence. His object was to prove the injustice of unearned income and private property by the assertion of the former doctrine, 'but the communistic tendencies which he borrowed from Owen prevented him from drawing its positive consequences' (Menger, p. 59). Thompson omitted from his treatise a chapter of a hundred pages on the institutions of society, on the ground that in the then existing state of public opinion his criticism would have caused unnecessary irritation. William Pare, his literary executor, also excluded this chapter from the 1850 and the 1869 editions. It was then probably lost or destroyed.
The fame of Thompson's works rests 'not upon his advocacy of Owenite co-operation, devoted and public-spirited as that was, but upon the fact that he was the first writer to elevate the question of the just distribution of wealth to the supreme position it has since held in English political economy. Up to his time political economy had been rather commercial than industrial' (Foxwell).
According to Professor Menger, 'from Thompson's book the later socialists, the Saint-Simonians, the Proudhons, and above all Marx and Rodbertus, have directly or indirectly drawn their opinions' (The Right to the whole Produce of Labour, Engl. trans. 1899, p. 51). Marx quotes Thompson, although he fails to give him credit for the discovery of the theory of surplus value.
In his 'Distribution of Wealth' Thompson incidentally advocated the equal economic and political rights of men and women. He deplored what he regarded as the fatal consequences of depriving women of the educational advantages enjoyed by men. 'Give men and women,' he says, 'equal civil and political rights.' Thompson expounded his ideas on sexual equality into a volume with the title of 'Appeal of One Half the Human Race, Women, against the Pretentions of the other Half, Men, to retain them in Political, and thence in Civil and Domestic, Slavery' (1825). This work was largely aimed at a passage in James Mill's 'Essay on Government,' and it had great influence in moulding John Stuart Mill's views on the same subject. J. S. Mill met Thompson when he came to London about 1827. Mill notes in his 'Autobiography' (p. 125) that at the free debates held weekly at the Co-operation (Owenite) Society's rooms in Chancery Lane, 'the principal champion on their (the Owenite) side was a very estimable man with whom I was well acquainted, Mr. William Thompson of Cork, author of a book on the distribution of wealth, and of an " Appeal " on behalf of women against the passage relating to them in my father's " Essay on Government." '
Thompson was also the author of the following works : 'Labour Rewarded ; The Claims of Labour and Capital Conciliated, or how to secure to Labour the whole Products of its Exertions. By one of the Idle Classes,' London, 8vo, 1827 (see Graham Wallas, Life of Francis Place, pp. 268-9) ; and 'Practical Directions for the Speedy and Economical Establishment of Communities on the Principles of Mutual Co-operation, United Possessions, and Equality of Exertions, and of the Means of Enjoyment,' London, 8vo, 1830.
For the last twenty years of his life
