In classical Hermetic texts you often see meditations designed to help the practitioner overcome perceived limitations and reach beyond his or herself. Often these techniques would involve training the imagination.
Sometimes these imagination exercises would take the formal systematic format we tend to favour nowadays, whereby the student would slowly build up their abilities in a scientific way. However more often the exercises had the feel of someone dynamically reaching forth, exploring the limits of their mental abilities using their imagination. Think of it as someone learning to pearl dive by playing in the water with skilled divers rather than through formal lessons.
The following is an extract from the Corpus Hermetica describing an exercise called Becoming Aeon. In this we are encouraged to step beyond ourselves and are reminded that humans are not confined to their body and living environment in the same way fishes are to the sea, or gods are to heaven, but can, through the power of their mind, be in all these places. Indeed, not only can you overcome the barriers of space, but time can also be overcome by picturing yourself at the dawn of existence, in the womb, or even the soul before entering the body and after leaving it.
To the Hermeticist, creation of forms in the imagination is not a flight of fantasy or a simple daydream, it’s a way of seeing the invisible, of reaching the great beyond and real training for immortality. In truth becoming immortal is just a matter of will: ‘You can even become a god if you want, for it is possible. Therefore want and understand and believe and love: then you have become it!’
Consider this yourself. Command your soul to go anywhere, and it will be there quicker than your command. Bid it to go to the ocean and again it is there at once, not as if it had gone from place to place but was’ already there. Order it to fly up to heaven and it will need no wings, nor will anything impede it, neither the fire of the sun, nor the ether, nor the whirlwind, nor the other heavenly bodies, but cutting through them all it will soar up to the last body. And if you wish to break through all this and to contemplate what is beyond (if there is anything beyond the cosmos), it is in your power.
See what power you have and what speed! You can do all these things and yet God cannot? Reflect on God in this way as having all within Himself as ideas: the cosmos, Himself, the whole. If you do not make yourself equal to God you cannot understand Him. Like is understood by like. Grow to immeasurable size. Be free from every body, transcend all time. Become eternity and thus you will understand God. Suppose nothing to be impossible for yourself. Consider yourself immortal and able to understand everything: all arts, sciences and the nature of every living creature.
Become higher than all heights and lower than all depths. Sense as one within yourself the entire creation: fire, water, the dry and the moist. Conceive yourself to be in all places at the same time: in earth, in the sea, in heaven; that you are not yet born, that you are within the womb, that you are young, old, dead; that you are beyond death.
Conceive all things at once: times, places, actions, qualities and quantities; then you can understand God. But if you lock up your soul in your body, abase it and say: ‘I understand nothing; I can do nothing; I am afraid of the sea; cannot reach heaven; I do not know who I was nor who I shall be.’ What have you to do with God?
For you cannot conceive anything beautiful or good while you are attached to the body and are evil. For the greatest evil is to ignore what belongs to God. To be able to know and to will and to hope is the straight and easy way appropriate to each that will lead to the Supreme Good. When you take that road this Good will meet you everywhere and will be experienced everywhere, even where and when you do not expect it; when awake, asleep, in a ship, on the road, by night, by day, when speaking . and when silent, for there is nothing which it is not.