[Side-note: The Kosmos is product of joint action of Reason and Necessity. The four visible and tangible elements are not primitive.] At this point of the exposition, the Platonic Timæus breaks off the thread, and takes up a new commencement. Thus far (he says) we have proceeded in explaining the part of Reason or Intelligence in the fabrication of the Kosmos. We must now explain the part of Necessity: for the genesis of the Kosmos results from co-operation of the two. By necessity (as has been said before) Plato means random, indeterminate, chaotic, pre-existent, spontaneity of movement or force: spontaneity ([Greek: ê( planôme/nê ai)ti/a]) upon which Reason works by persuasion up to a certain point, prevailing upon it to submit to some degree of fixity and regularity.[63] Timæus had described the body of the Kosmos as being constructed by the Demiurgus out of the four elements; thus assuming fire, air, earth, water, as pre-existent. But he now corrects himself, and tells us that such assumption is unwarranted. We must (he remarks) give a better and fuller explanation of the Kosmos. No one of these four elements is either primordial, or permanently distinct and definite in itself. [Footnote 63: Plato, Timæus, p. 48 A.] The only primordial reality is, an indeterminate, all-recipient _fundamentum_: having no form or determination of its own, but capable of receiving any form or determination from without. [Side-note: Forms or Ideas and Materia Prima--Forms of the Elements--Place, or Receptivity.] In the second explanation now given by Plato of the Kosmos and its genesis, he assumes this invisible _fundamentum_ (which he had not assumed before) as "the mother or nurse of all generation". He assumes, besides, the eternal Forms or Ideas, to act upon it and to bestow determination or quality. These forms fulfil the office of father: the offspring of the two is--the generated, concrete, visible, objects,[64] imitations of the Forms or Ideas, begotten out of this mother. How the Ideas act upon the Materia Prima, Plato cannot well explain: but each Form stamps an imitation or copy of itself upon portions of the common _Fundamentum_.[65] [Footnote 64: Plato, Timæus, p. 51 A. [Greek: tê\n tou= gegono/tos o(ratou= kai\ pa/ntôs ai)sthêtou= mête/ra kai\ u(podochê/n.]] [Footnote 65: Plato, Timæus, pp. 50-51. 50 C: [Greek: tupôthe/nta a)p' au)tô=n tro/pon tina\ du/sphraston kai\ thaumasto/n.] 51 A: [Greek: a)no/raton ei)=do/s ti, kai\ a)/morphon, pandeche/s, _metalamba/non de\ a)porô/tata/ pê| tou= noêtou=_ kai\ dusalôto/taton.]] But do there really exist any such Forms or Ideas--as Fire _per se_, the Generic Fire--Water _per se_, the Generic Water, invisible and intangible?[66] Or is this mere unfounded speech? Does there exist nothing really anywhere, beyond the visible objects which we see and touch?[67] [Footnote 66: Plato, Timæus, p. 51 C.]