Put shortly, the main positions are these.  In the state of nature each man lived in entire isolation, and therefore physical inequality was as if it did not exist.  After many centuries, accident, in the shape of difference of climate and external natural conditions, enforcing for the sake of subsistence some degree of joint labour, led to an increase of communication among men, to a slight development of the reasoning and reflective faculties, and to a rude and simple sense of mutual obligation, as a means of greater comfort in the long run.  The first state was good and pure, but the second state was truly perfect.  It was destroyed by a fresh succession of chances, such as the discovery of the arts of metal-working and tillage, which led first to the institution of property, and second to the prominence of the natural or physical inequalities, which now began to tell with deadly effectiveness.  These inequalities gradually became summed up in the great distinction between rich and poor; and this distinction was finally embodied in the constitution of a civil society, expressly adapted to consecrate the usurpation of the rich, and to make the inequality of condition between them and the poor eternal.

We thus see that the Discourse, unlike Morelly’s terse exposition, contains no clear account of the kind of inequality with which it deals.  Is it inequality of material possession or inequality of political right?  Morelly tells you decisively that the latter is only an accident, flowing from the first; that the key to renovation lies in the abolition of the first.  Rousseau mixes the two confusedly together under a single name, bemoans each, but shrinks from a conclusion or a recommendation as to either.  He declares property to be the key to civil society, but falls back from any ideas leading to the modification of the institution lying at the root of all that he deplores.

The first general criticism, which in itself contains and covers nearly all others, turns on Method.  “Conjectures become reasons when they are the most likely that you can draw from the nature of things,” and “it is for philosophy in lack of history to determine the most likely facts.”  In an inductive age this royal road is rigorously closed.  Guesses drawn from the general nature of things can no longer give us light as to the particular nature of the things pertaining to primitive men, any more than such guesses can teach us the law of the movement of the heavenly bodies, or the foundations of jurisprudence.  Nor can deduction from anything but propositions which have themselves been won by laborious induction, ever lead us to the only kind of philosophy which has fair pretension to determine the most probable of the missing facts in the chain of human history.  That quantitative and differentiating knowledge which is science, was not yet thought of in connection with the movements of our own race upon the earth.  It is to be said, further, that of the two possible ways of guessing about the early state, the conditions of advance from it, and the rest, Rousseau’s guess that all movement away from it has been towards corruption, is less supported by subsequent knowledge than the guess of his adversaries, that it has been a movement progressive and upwards.