The view here taken by Plato, that all nature is cognate and interdependent — ἅτε γὰρ τῆς φύσεως ἁπάσης συγγενοῦς οὔσης — is very similar to the theory of Leibnitz:— “Ubique per materiam disseminata statuo principia vitalia seu percipientia. Omnia in naturâ sunt analogica” (Leibnitz, Epist. ad Wagnerum, p. 466; Leibn. Opp. Erdmann). Farther, that the human mind by virtue of its interdependence or kindred with all nature, includes a confused omniscience, is also a Leibnitzian view. “Car comme tout est plein (ce qui rend toute la matière liée) et comme dans le plein tout mouvement fait quelqu’ effet sur les corps distans à mesure de la distance, de sorte que chaque corps est affecté non seulement par ceux qui le touchent, et se ressent en quelque façon de tout ce qui leur arrive — mais aussi par leur moyen se ressent de ceux qui touchent les premiers dont il est touché immédiatement. Il s’ensuit que cette communication va à quelque distance que ce soit. Et par consequent tout corps se ressent de tout ce qui se fait dans l’Univers: tellement que celui, qui voit tout, pourroit lire dans chacun ce qui se fait partout et même ce qui s’est fait et se fera, en remarquant dans le présent ce qui est éloigné tant selon les temps que selon les lieux: σύμπνοια πάντα, disoit Hippocrate. Mais une âme ne peut lire en elle même que ce qui y est representé distinctement: elle ne sauroit developper tout d’un coup ses règles, car elles vont à l’infini. Ainsi quoique chaque monade créée représente tout l’Univers, elle représente plus distinctement le corps qui lui est particulièrement affecté, et dont elle fait l’Entéléchie. Et comme ce corps exprime tout l’Univers par la connexion de toute la matière dans le plein, l’âme représente aussi tout l’Univers en représentant ce corps qui lui appartient d’une manière particulière” (Leibnitz, Monadologie, sect. 61-62, No. 88, p. 710; Opp. Leibn. ed. Erdmann).
Again, Leibnitz, in another Dissertation: “Comme à cause de la plénitude du monde tout est lié, et chaque corps agit sur chaque autre corps, plus ou moins, selon la distance, et en est affecté par la réaction — il s’ensuit que chaque monade est un miroir vivant, ou doué d’action interne, représentatif de l’Univers, suivant son point de vue, et aussi réglé que l’Univers même” (Principes de la Nature et de la Grace, p. 714, ed. Erdmann; also Système Nouveau, p. 128, a. 36).
Leibnitz expresses more than once how much his own metaphysical views agreed with those of Plato. Lettre à M. Bourguet, pp. 723-725. He expresses his belief in the pre-existence of the soul: “Tout ce que je crois pouvoir assurer, est, que l’âme de tout animal a préexisté, et a été dans un corps organique: qui enfin, par beaucoup de changemens, involutions, et évolutions, est devenu l’animal présent” (Lettre à M. Bourguet, p. 731). And in the Platonic doctrine of reminiscence to a certain point: “II y a quelque chose de solide dans ce que dit Platon de la réminiscence” (p. 137, b. 10). Also Leibnitz’s Nouveaux Essais sur l’Entendement Humain, p. 196, b. 28; and Epistol. ad Hanschium, p. 446, a. 12.
See the elaborate account of the philosophy of Leibnitz by Dr. Kuno Fischer — Geschichte der neueren Philosophie, vol. ii. pp. 226-232.
[41] Plato, Menon, p. 81 D. ἐάν τις ἀνδρεῖος ᾖ, καὶ μὴ ἀποκάμνῃ ζητῶν. Compare also p. 86 B.
Plato’s view of the immortality of the soul — difference between the Menon, Phædrus, and Phædon.
In various other dialogues of Plato, the same hypothesis is found repeated. His conception of the immortality of the soul or mind, includes pre-existence as well as post-existence: a perpetual succession of temporary lives, each in a distinct body, each terminated by death, and each followed by renewed life for a time in another body. In fact, the pre-existence of the mind formed the most important part of Plato’s theory about immortality: for he employed it as the means of explaining how the mind became possessed of general notions. As the doctrine is stated in the Menon, it is made applicable to all minds (instead of being confined, as in Phædrus, Phædon, and elsewhere, to a few highly gifted minds, and to commerce with the intelligible substances called Ideas). This appears from the person chosen to illustrate the alleged possibility of stimulating artificial reminiscence: that person is an unlettered youth, taken at hazard from among the numerous slaves of Menon.[42]
[42] Plato, Menon, pp. 82 A, 85 E. προσκάλεσον τῶν πολλῶν ἀκολούθων τουτωνὶ τῶν σαυτοῦ ἕνα, ὅντινα βούλει, ἵνα ἐν τούτῳ σοι ἐπιδείξωμαι. Stallbaum says that this allusion to the numerous slaves in attendance is intended to illustrate conspicuously the wealth and nobility of Menon. In my judgment, it is rather intended to illustrate the operation of pure accident — the perfectly ordinary character of the mind worked upon — “one among many, which you please”.
Doctrine of Plato, that new truth may be elicited by skilful examination out of the unlettered mind — how far correct?
It is true, indeed (as Schleiermacher observes), that the questions put by Sokrates to this youth are in great proportion leading questions, suggesting their own answers. They would not have served their purpose unless they had been such. The illustration here furnished, of the Sokratic interrogatory process, is highly interesting, and his theory is in a great degree true.[43] Not all learning, but an important part of learning, consists in reminiscence — not indeed of acquisitions made in an antecedent life, but of past experience and judgments in this life. Of such experience and judgments every one has travelled through a large course; which has disappeared from his memory, yet not irrevocably. Portions of it may be revived, if new matter be presented to the mind, fitted to excite the recollection of them by the laws of association. By suitable interrogations, a teacher may thus recall to the memory of his pupils many facts and judgments which have been hitherto forgotten: he may bring into juxtaposition those which have never before been put together in the mind: and he may thus make them elicit instructive comparisons and inferences. He may provoke the pupils to strike out new results for themselves, or to follow, by means of their own stock of knowledge, in the path suggested by the questions. He may farther lead them to perceive the fallacy of erroneous analogies which at first presented themselves as plausible; and to become painfully sensible of embarrassment and perplexing ignorance, before he puts those questions which indicate the way of escape from it. Upon the necessity of producing such painful consciousness of ignorance Plato insists emphatically, as is his custom.[44]