Given the fact that philosophy is more evidently quest for wisdom than possession of wisdom, the education of the philosopher never ceases as long as he lives; it is the adult education par excellence. For, to say nothing of other things, the highest kind of knowledge which a man may have acquired can never be simply at his disposal as other kinds of knowledge can; it is in constant need of being acquired again from the start. This leads to the following consequence. In the case of the gentleman, one can make a simple distinction between the playful education of the potential gentleman and the earnest work of the gentleman proper. In the case of the philosopher this simple distinction between the playful and the serious no longer holds, not in spite of the fact that his sole concern is with the weightiest matters but because of it. For this reason alone, the rule of philosophers proves to be impossible.
What do the " playful education" and " earnest work" mean ? Thanks!
Playful education could be learning the rules of whist or evaluating Napoleon's tacticts in Belgium.
Earnest work would probably be something like contemplating the true nature of beauty and truth.