This letter is neither very complimentary nor very conclusive in its treatment of Rousseau's position, but it may be said to mark his official reception into the guild of literary men. He was presently engaged in new work. He wrote an article on Political Economy for the great "Encyclopaedia," in which, reversing the teaching of the Second Discourse, he maintains that "it is certain that the right of property is the most sacred of all the rights of citizens, and more important in some respects than liberty itself; either because it more closely concerns the preservation of life, or because, property being easier to take away and harder to defend than persons, that should be most respected which is most easily ravished; or again, because property is the true foundation of civil society, and the true guarantee of the engagements of the citizens; for if property did not answer for persons, nothing would be so easy as to elude duties and to laugh at the laws."[Footnote: Rousseau, _Oeuvres_, xii. 41.] And further on, in the same article, he calls property the foundation of the social compact, whose first condition is that every one be maintained in the peaceful enjoyment of what belongs to him. We must not wonder at seeing Rousseau thus change sides from day to day. A dreamer and not a philosophic thinker, he perceived some truths and uttered many sophistries, speaking always with the fire of conviction and a fatal eloquence. It is needless to enter into the detail of Rousseau's life at this time, the time when his most remarkable work was done. Labor was always painful and irritating to him, and it was perhaps the irksomeness of his tasks that drove him into something not unlike madness.[Footnote: There is little doubt that Rousseau was at one time really insane, subject to the delusion that he was being persecuted. His insanity did not become very marked until the time of the real persecutions undergone after the publication of _Émile_. See his Biographies and _Le Docteur Châtelain, La folie de J. J. Rousseau_, Paris, 1890. He was, of course, always eccentric and ill balanced; and was often rendered irritable by a painful disease, caused by a malformation of the bladder. Morley, _Rousseau_, i. 277, etc. _Oeuvres_, xviii. 155 (_Conf._ Part. ii. liv. viii.).] Yet he kept on writing with enthusiasm. He speaks of himself as moved in these years by the contemplation of great objects; ridiculously hoping to bring about the triumph of reason and truth over prejudice and lies, and to make men wiser by showing them their true interests. He learned at this time, he says, to meditate profoundly, and for a moment astonished Europe by productions in which vulgar souls saw only eloquence and wit, but in which those persons who inhabit ethereal regions joyfully recognized one of their own kind.[Footnote: Rousseau, _Oeuvres_, xx. 275 (II. Dialogue).]