The unity asserted by Xenophanes gave its motto to the Eleatic school; #hen ta panta# became their watchword. Parmenides, however, abstracted from this unity all theological attributes. Plain existence, obtained apparently by divesting thought of all qualifications derived from sensation and imagination, and regarding it in primitive and abstract nakedness or nothingness, was the only positive condition which he left to the principle of Being; and though he seems to have identified this Being with Thought, we must be careful not to be misled by modern analogies into fancying that his #archê# involved a purely intellectual idealism. Nor, again, can we regard it as the totality of things presented to the senses; the most earnest polemic of the philosopher is directed against this view. The Unity, the Being, of Parmenides, was in truth the barest metaphysical abstraction, deduced, we are tempted to believe, in the first instance from a simple observation of language, and yet, when formed, not wholly purged from corporeity. Being is proved by the word #esti#. The singular number indicates the unity of the subject; the present tense proves its eternity, for it neither asserts a _has been_ nor a _will be_, but an everlasting _is_. Its antithesis not-Being is impossible and inconceivable; #ouk esti#. Completing his conception of Being as the sole reality, and carrying out the arguments attributed by Aristotle to his master,[46] Parmenides shows that the eternal One is indivisible, immovable, continuous, homogeneous, absolutely self-identical, beyond the reach of birth, or change, or dissolution. Furthermore, it is finite and spheroid. In rounding and completing his notion of the Unity of Being, Parmenides seems at this point to have passed into the region of geometrical abstractions. The sphere of mathematics requires to be circumscribed by a superficies equidistant at all points from the centre. These conditions of perfection Parmenides attributed to Being, forgetting that the finite sphere thus conceived by him implied, by a necessity of human thought, a beyond against which it should be defined. At the same time, this geometrical analogy prevents us from assuming that the further identification of Being with Thought excluded a concrete and almost material conception of the Ens.