Tao, as spoken of by Lao-tzŭ, may be considered as a potential or as an actual existence, and under this latter head it may be contemplated in itself and as an operating agent in the universe. Regarded as a potential existence it may, when compared with actual existence, be pronounced non-existence. It is from this point of view imperceptible to man, and can be spoken of only negatively; and so such terms as non-existence (無), the unlimited or infinite (無極), the non-exerting (無爲), the matterless (無物), are the expressions used with reference to Tao thus considered.[4] Accordingly Lao-tzŭ, when speaking of it as a potential existence, as the logical antecedent of all perceptible existence—seems to regard it as equivalent to the primeval Nothing or Chaos. So too the Yuan-miao-nei-pʽien (元妙内篇) says that the great Tao which arose in non-exertion is the ancestor of all things.[5] From this state, however, it passes into the condition of actual existence, a transition which is expressed under the metaphor of generation.[6] To this doctrine, that existence is generated from non-existence, Chu-hsi objects; but his objection arises chiefly, I think, from supposing that Lao-tzŭ regarded them as two distinct things, whereas his doctrine on this subject is exactly like that of Chou-tzŭ, with which Chu-hsi seems to agree.[7] We are not to suppose that Nature is ever simply and entirely potential to the utter exclusion of actuality, or _vice versa_: on the contrary, these two existences or conditions are represented as alternately generating each the other.[8] Thus the potential (or nominal non-existence) may be supposed to be in time later than the actual, though the latter must always be logically regarded as consequent on the former. In itself, again, _Tao_, regarded as an actual existence is, as has been seen, calm, void, eternal, unchanging and bare of all qualities. Regarded as an agent operating throughout the universe, on the other hand, _Tao_ may be spoken of as great, changing, far-extending, and finally returning (to the state of potentiality).[9] A late author gives a curious illustration of the above notions of Lao-tzŭ, taken from the well-known habits of the Ateuchus with reference to the propagation of its species, but this author proceeds on the supposition that non-existence and existence are different. We have now to combine these two conceptions of Tao, as a potential and as an actual existence. Though void, shapeless, and immaterial, it yet contains the potentiality of all substance and shape, and from itself it produces the universe,[10] diffusing itself over or permeating all space. It is said to have generated the world,[11] and is frequently spoken of as the mother of this latter[12]—“the dark primeval mother, teeming with dreamy beings.” All things that exist submit to Tao as their chief, but it displays no lordship over them.[13] In the spring time it quickens the dead world, clothes it as with a garment, and nourishes