Philo Judaeus De Ebrietate 158

For knowledge, which is the opposite of ignorance, may be called, in a manner, the eyes and ears of the soul; for it applies the mind to what is said, and fixes its eyes upon things as they exist, and cannot endure to form a false judgment of anything which it either sees or hears. But it examines and carefully surveys every object which is worthy of being seen or heard, and even if it be necessary to sail or to travel over sea and land, it will traverse them to its furthest boundaries that it may see anything more important, or hear anything more modern;