Apart from Ontology, Parmenides reckons all as belonging to human opinions. These were derived from the observations of sense (which he especially excludes from Ontology) with the comparisons, inferences, hypothesis, &c., founded thereupon: the phenomena of Nature generally.[68] He does not attempt (as Plato and Aristotle do after him) to make Ontology serve as a principle or beginning for anything beyond itself,[69] or as a premiss from which the knowledge of nature is to be deduced. He treats the two — Ontology and Phenomenology, to employ an Hegelian word — as radically disparate, and incapable of any legitimate union. Ens was essentially one and enduring: Nature was essentially multiform, successive, ever changing and moving relative to the observer, and different to observers at different times and places. Parmenides approached the study of Nature from its own starting point, the same as had been adopted by the Ionic philosophers — the data of sense, or certain agencies selected among them, and vaguely applied to explain the rest. Here he felt that he relinquished the full conviction, inseparable from his intellectual consciousness, with which he announced his few absolute truths respecting Ens and Non-Ens, and that he entered upon a process of mingled observation and conjecture, where there was great room for diversity of views between man and man.
[68] Karsten observes that the Parmenidean region of opinion comprised not merely the data of sense, but also the comparisons, generalisations, and notions, derived from sense.
“Δοξαστὸν et νοητὸν vocantur duo genera inter se diversa, quorum alterum complectitur res externas et fluxas, notionesque quæ ex his ducuntur — alterum res æternas et à conspectu remotas,” &c. (Parm. Fragm. p. 148-149).
[69] Marbach (Lehrbuch der Gesch. der Philos., s. 71, not. 3) after pointing out the rude philosophical expression of the Parmenidean verses, has some just remarks upon the double aspect of philosophy as there proclaimed, and upon the recognition by Parmenides of that which he calls the “illegitimate” vein of enquiry along with the “legitimate.”
“Learn from me (says Parmenides) the opinions of mortals, brought to your ears in the deceitful arrangement of my words. This is not philosophy (Marbach says): it is Physics. We recognise in modern times two perfectly distinct ways of contemplating Nature: the philosophical and the physical. Of these two, the second dwells in plurality, the first in unity: the first teaches everything as infallible truth, the second as multiplicity of different opinions. We ought not to ask why Parmenides, while recognising the fallibility of this second road of enquiry, nevertheless undertook to march in it, — any more than we can ask, Why does not modern philosophy render physics superfluous?”
The observation of Marbach is just and important, that the line of research which Parmenides treated as illegitimate and deceitful, but which he nevertheless entered upon, is the analogon of modern Physics. Parmenides (he says) indicated most truly the contrast and divergence between Ontology and Physics; but he ought to have gone farther, and shown how they could be reconciled and brought into harmony. This (Marbach affirms) was not even attempted, much less achieved, by Parmenides: but it was afterwards attempted by Plato, and achieved by Aristotle.
Marbach is right in saying that the reconciliation was attempted by Plato; but he is not right (I think) in saying that it was achieved by Aristotle — nor by any one since Aristotle. It is the merit of Parmenides to have brought out the two points of view as radically distinct, and to have seen that the phenomenal world, if explained at all, must be explained upon general principles of its own, raised out of its own data of facts — not by means of an illusory Absolute and Real. The subsequent philosophers, in so far as they hid and slurred over this distinction, appear to me to have receded rather than advanced.
Parmenides recognises no truth, but more or less probability, in phenomenal explanations. — His physical and astronomical conjectures.
Yet though thus passing from Truth to Opinions, from full certainty to comparative and irremediable uncertainty,[70] Parmenides does not consider all opinions as equally true or equally untrue. He announces an opinion of his own — what he thinks most probable or least improbable — respecting the structure and constitution of the Kosmos, and he announces it without the least reference to his own doctrines about Ens. He promises information respecting Earth, Water, Air, and the heavenly bodies, and how they work, and how they came to be what they are.[71] He recognises two elementary principles or beginnings, one contrary to the other, but both of them positive — Light, comprehending the Hot, the Light, and the Rare — Darkness, comprehending the Cold, the Heavy, and the Dense.[72] These two elements, each endued with active and vital properties, were brought into junction and commixture by the influence of a Dea Genitalis analogous to Aphroditê,[73] with her first-born son Eros, a personage borrowed from the Hesiodic Theogony. From hence sprang the other active forces of nature, personified under various names, and the various concentric circles or spheres of the Kosmos. Of those spheres, the outer-most was a solid wall of fire — “flammantia mœnia mundi” — next under this the Æther, distributed into several circles of fire unequally bright and pure — then the circle called the Milky Way, which he regarded as composed of light or fire combined with denser materials — then the Sun and Moon, which were condensations of fire from the Milky Way — lastly, the Earth, which he placed in the centre of the Kosmos.[74] He is said to have been the first who pronounced the earth to be spherical, and even distributed it into two or five zones.[75] He regarded it as immovable, in consequence of its exact position in the centre. He considered the stars to be fed by exhalation from the Earth. Midway between the Earth and the outer flaming circle, he supposed that there dwelt a Goddess — Justice or Necessity — who regulated all the movements of the Kosmos, and maintained harmony between its different parts. He represented the human race as having been brought into existence by the power of the sun,[76] and he seems to have gone into some detail respecting animal procreation, especially in reference to the birth of male and female offspring. He supposed that the human mind, as well as the human body, was compounded of a mixture of the two elemental influences, diffused throughout all Nature: that like was perceived and known by like: that thought and sensation were alike dependent upon the body, and upon the proportions of its elemental composition: that a certain limited knowledge was possessed by every object in Nature, animate or inanimate.[77]
[70] Parmen. Fr. v. 109.