The Power of Mind

I am reading The Good Book: A Humanist Bible by A.C. Grayling and came upon something I would like to share. 

The following is from the Parables, Chapter 13: In ancient Athens the philosopohers thought out their best ideas walking up and down their groves; nature sobers us and instructs us. When we look up at the night sky we are giddied by its vastness, and the immense distance of the stars; And when we look down the steeps of a mountain into the abyss below, we nearly fall; And when the moon paints everything silver and white in the stillness of night, when all others sleep and only we ourselves wake, and are watchful and sad, Then we hear the voice of thought, and come face to face with ourselves, with the brevity of life, with the lack of all we once had and have lost; And yet, also, once we have been patient awhile and continued to listen, we come face to face with hope. For we learn then, if we are brave, the power of mind, which is the greatest thing in man; of how, though man is small before nature, his mind can encompass all nature, In thinking of it, and singing about it, searching it in science, and celebrating it in poetry. So I think all the sages found both courage and modesty through the mind's contact with nature, and these two things are the begetters of hope. Is there proof that they were right to hope? Well, only consider: it is many centuries since the first sages paced their groves, and their words and thoughts are with us today, and we speak of them; Though nature conquered their bodies and their bodies are dispersed into the elements once more, the fruit of their minds is with us still. I like to think of the philosophers walking in their groves. What a mistake it is to stop the child fidgeting (so they call it) over his book, for the body must be active as the mind learns. It would be best to teach children while walking in a meadow. You see the scholars swaying as they recite their texts; mind is part of the dance; let the body be active when the mind is active too. Though it is good to be in the kingdom of one's library, walking with the greatest of the past in thought, it is good to takethe thoughts thus acquired into the air, For though it is true that literature is the criticism of life, so is it also true that life is the criticism of learning. Another of the sayings written on our city walls is this: let the door to the library of the world open from the library of one's books, and vice versa.