The mind is still trying to understand itself

In the middle of a discussion of comets Seneca gives us this nugget about the human mind:

"there are many things that we admit exist, but we do not know what they are like. Everybody will agree that we have a mind, by whose commands we are driven on and called back. But what the mind is, this controller and master of ours, no one will explain to you, any more than he will explain where it is: one person will say that it is breath, another that it is a kind of harmony, another that it is a divine power, a portion of god, another that it is the finest part of the soul, another that it is an incorporeal power; someone will be found to say it is blood or heat. So far from being able to acquire a clear grasp of other things, the mind is still trying to understand itself".

- Seneca, Natural questions 7.25.1