You must be taught before you can write or read. It's even more true with life. You are born a slave to your senses and animal impulses. Without teaching, you have no real knowledge or sound judgment.
In matter of writing or reading thou must needs be taught before thou can do either: much more in matter of life. 'For thou art born a mere slave, to thy senses and brutish affections;' destitute without teaching of all true knowledge and sound reason.
Think of how Socrates looked when he had to wrap himself in an animal skin. His wife Xanthippe had taken his clothes and gone out with them. His friends felt embarrassed for him and started to leave when they saw him dressed this way. But notice what he said to them.
How Socrates looked, when he was fain to gird himself with a skin, Xanthippe his wife having taken away his clothes, and carried them abroad with her, and what he said to his fellows and friends, who were ashamed; and out of respect to him, did retire themselves when they saw him thus decked.