[Footnote 794: ][ (return) ] Diogenes Laertius, "Lives of the Philosophers," bk. x. ch. xxiv.
The atoms are not all of one form, but of different forms suited to the production of different substances by combination; some are square, some triangular, some smooth and spherical, some are hooked with points. They are also diversified in magnitude and density. The number of original forms is "incalculably varied," but not infinite. "Every variety of forms contains an infinitude of atoms, but there is not, for that reason, an infinitude of forms; it is only the number of them which is beyond computation." [795] To assert that atoms are of every kind of form, magnitude, and density, would be "to contradict the phenomena; "for experience teaches us that objects have a finite magnitude, and form necessarily supposes limitation.
[Footnote 795: ][ (return) ] Id., ib.
A variety of these primordial forms enter into the composition of all sensible objects, because sensible objects possess different qualities, and these diversified qualities can only result from the combination of different original forms. "The earth has, in itself, primary atoms from which springs, rolling forth cool water, incessantly recruit the immense sea; it has also atoms from which fire arises.... Moreover, the earth contains atoms from which it can raise up rich corn and cheerful groves for the tribes of men...." So that "no object in nature is constituted of one kind of elements, and whatever possesses in itself must numerous powers and energies, thus demonstrates that it contains more numerous kinds of primary particles," [796] or primordial "seeds of things."
"The atoms are in a continual state of motion" and "have moved with equal rapidity from all eternity, since it is evident the vacuum can offer no resistance to the heaviest, any more than the lightest." The primary and original movement of all atoms is in straight lines, by virtue of their own weight. The vacuum separates all atoms one from another, at greater or less distances, and they preserve their own peculiar motion in the densest substances. [797]
[Footnote 796: ][ (return) ] Lucretius, "On the Nature of Things," bk. i. l. 582-600.
[Footnote 797: ][ (return) ] Diogenes Laertius, "Lives of the Philosophers," bk. x. ch. xxiv.; Lucretius, "On the Nature of Things," bk. i. l. 80-92.
And now the grand crucial question arises--How do atoms combine so as to form concrete bodies? If they move in straight lines, and with equal rapidity from all eternity, then they can never unite so as to form concrete substances. They can only coalesce by deviating from a straight line. [798] How are they made to deviate from a straight line? This deviation must be introduced arbitrarily, or by some external cause. And inasmuch as Epicurus admits of no causes "but space and matter," and rejects all divine or supernatural interposition, the new movement must be purely arbitrary. They deviate spontaneously, and of their own accord. "The system of nature immediately appears as a free agent, released from tyrant masters, to do every thing of itself spontaneously, without the help of the gods." [799] The manner in which Lucretius proves this doctrine is a good example of the petitio principii. He assumes, in opposition to the whole spirit and tendency of the Epicurean philosophy, that man has "a free will," and then argues that if man who is nothing but an aggregation of atoms, can "turn aside and alter his own movements," the primary elements, of which his soul is composed, must have some original spontaneity. "If all motion is connected and dependent, and a new movement perpetually arises from a former one in a certain order, and if the primary elements do not produce any commencement of motion by deviating from the straight line to break the laws of fate, so that cause may not follow cause in infinite succession, whence comes this freedom of will to all animals in the world? whence, I say, is this liberty of action wrested from the fates, by means of which we go wheresoever inclination leads each of us? whence is it that we ourselves turn aside, and alter our motions, not at any fixed time, nor in any fixed part of space, but just as our own minds prompt?.... Wherefore we must necessarily confess that the same is the case with the seeds of matter, and there is some other cause besides strokes and weight [resistance and density] from which this power [of free movement] is innate in them, since we see that nothing is produced from nothing." [800] Besides form, extension, and density, Epicurus has found another inherent or essential quality of matter or atoms, namely, "spontaneous" motion.
[Footnote 798: ][ (return) ] "At some time, though at no fixed and determinate time, and at some point, though at no fixed and determinate point, they turn aside from the right line, but only so far as you can call the least possible deviation."-- Lucretius, "On the Nature of Things," bk. ii. l. 216-222.
[Footnote 799: ][ (return) ] Lucretius, "On the Nature of Things" bk. ii. 1. 1092-1096.