Of all Socrates' disciples (many of whom were listed in the previous chapter), none surpass Plato. If philosophy has two sides--action and contemplation--and if Socrates was the master of the former and Pythagoras the master of the latter, then Plato is the one who synthesizes the two into a harmonic philosophical whole.
This whole philosophy Plato then divides into three parts: moral (how we live), natural (what we think about), and rational (telling what is true from what is false). Because of the way he writes, it can be hard to figure out exactly what Plato actually thinks about any of these issues: "that is, what he believed to be the end of all actions, the cause of all natures, and the light of all intelligences."
And yet, it will be useful to bring up a few of Plato's ideas, since he is (rightly) understood to be the chief of all the pagan philosophers, so far that there are those who follow Plato who
are said to have manifested the greatest acuteness in understanding him, do perhaps entertain such an idea of God as to admit that in Him are to be found the cause of existence, the ultimate reason for the understanding, and the end in reference to which the whole life is to be regulated. Of which three things, the first is understood to pertain to the natural, the second to the rational, and the third to the moral part of philosophy. For if man has been so created as to attain, through that which is most excellent in him, to that which excels all things,—that is, to the one true and absolutely good God, without whom no nature exists, no doctrine instructs, no exercise profits,—let Him be sought in whom all things are secure to us, let Him be discovered in whom all truth becomes certain to us, let Him be loved in whom all becomes right to us.In other words, Plato at least seems to be on the right track--we should seek God as the source of nature, knowledge, and the moral life. Whether Plato has arrived there has yet to be seen.
Plato's claim that the wise man is the "one who imitates, knows, loves this God, and who is rendered blessed through fellowship with Him in His own blessedness," so "why discuss with the other philosophers?"
The civil/mythical philosophies discussed interminably in book VII and the pre-Socratic speculations on the nature of the physical world and even the more recent Epicureans and Stoics all ought to give way to the Platonists, who alone rise above crass materialism (however well dressed up in philosophical rhetoric) to the understanding that what matters most is spiritual life. Now we can have a meaningful philosophical discussion.