=216.= We may sum up the history of the universe according to the Stoics somewhat in the following way. Body is neither burden on the soul nor its instrument, but all body is of itself instinct with motion, warmth, and life, which are essentially the same. This motion is not entirely that of contraction, or immobility would result; nor entirely that of expansion, else the universe would be scattered into the far distance[145]. One of these motions constantly succeeds the other, as Heraclitus says ‘becoming extinguished by measure, and catching light by measure[146]’; as when a swimmer with all his strength can just hold his own against the force of the stream, or a bird straining its pinions appears to rest suspended in the air[147]. At the beginning of each world-period expansion or tension is supreme, and only the world-soul exists. Next the fiery breath begins to cool, the opposing principle of contraction asserts itself, the universe settles down and shrinks; the aether passes into air, and air in its turn to water. All this while tension is slackening, first in the centre, lastly even in the circumference; yet the vital force is not entirely quenched; beneath the covering of the waters lurks the promise of a new world. The fire still unextinguished within works upon the watery mass or chaos until it evolves from it the four elements as we know them. On its outer edge where it meets the expansive aether, the water rarefies until the belt of air is formed. All the while the outward and inward movements persist; particles of fire still pass into air, and thence into water and earth. Earth still in turn yields to water, water to air, and air to fire (ὁδὸς ἄνω κάτω). Thus by the interaction of conflicting tendencies an equilibrium (ἰσονομία) is established, and the result is the apparent permanence of the phenomenal world[148]. Finally the upward movement becomes slightly preponderant, water becomes absorbed in air and air transformed into fire, once more the conflagration results and all the world passes into the fiery breath from which it came[149]. FOOTNOTES [1] As, for instance, Aristophanes in the _Clouds_. [2] ‘vos etiam dicitis esse e regione nobis, e contraria parte terrae, qui adversis vestigiis stent contra nostra vestigia, quos Antipodas vocatis’ Cic. _Ac._ ii 39, 123. [3] ‘cum tu, inter scabiem tantam et contagia lucri, | nil parvum sapias et adhuc sublimia cures; | quae mare compescant causae; quid temperet annum; | stellae sponte sua iussaene vagentur et errent’ Hor. _Ep._ i 12, 14-17. [4] Sen. _Ben._ iv 23, 2 to 4. [5] ‘in aperto iacentes sidera superlabebantur et insigne spectaculum noctium. mundus in praeceps agebatur silentio tantum opus ducens ... libebat intueri signa ex media caeli parte vergentia, rursus ex occulto alia surgentia’ _Ep._ 90, 42.