It may be observed at this point that the conception of a “law of nature” made a very valuable middle term between the conception of a purely primitive condition of the world and the ideal of a complete society. The logical reason is plain. The instinct of getting at something solid and permanent, which first reveals itself by going back to the supposed original or simple, soon attaches itself also to what is _generally_ found to exist, understanding generality as a mark of that tendency to come of itself which it feels to attach to what is real and able to stand in its own right. But generality is a clue which leads a long way; and the mind passes from saying “Fire burns [1] by nature, {130} for it burns everywhere; but law is variable” [2] to observing that there are features of law which have their own generality, and there thus appears to be a “natural” element in law, which may mean the right of the strongest, [3] but may again amount to a tendency to come out of the “state of nature.” Just in the same way, the conception of Liberty has always drawn from experience a certain positive tendency to progress, and has never perhaps, even in the most fanatical theory, maintained the full demand for isolation which its negative bearing might seem to imply. [1] Argument cited by Aristotle, _Eth_., v. 10. [2] Just so, in strict science, from the Atomists downward, the primary qualities (spatial) are real, the secondary (colours) conventional (or, as we say, “subjective”); the former meaning holds good more generally than the latter. [3] Plato, _Gorgias_, p. 484. But again, the instinct which, in looking for what has power to grow or come of itself, lays hold of what is merely primitive or merely general, has in all great epochs of thought been met by a deeper insight.