Read the excerpt from The Republic by Plato.

But when a man’s pulse is healthy and temperate, and when before going to sleep he has awakened his rational powers, and fed them on noble thoughts and enquiries, collecting himself in meditation; after having first indulged his appetites neither too much nor too little, but just enough to lay them to sleep, and prevent them and their enjoyments and pains from interfering with the higher principle—which he leaves in the solitude of pure abstraction, free to contemplate and aspire to the knowledge of the unknown, whether in past, present, or future: when again he has allayed the passionate element, if he has a quarrel against any one—I say, when, after pacifying the two irrational principles, he rouses up the third, which is reason, before he takes his rest, then, as you know, he attains truth most nearly, and is least likely to be the sport of fantastic and lawless visions.

How does the phrase "free to contemplate and aspire to the knowledge of the unknown” support the speaker’s claim?

It solicits general feelings about what makes for a healthy state of mind.
It uses abductive reasoning to show how most people are able to think about issues.
It uses antithesis to contrast what is unknown with what is true.
It applies logos by showing what can be accomplished with the mindset described.