The Psychology of Kundalini Yoga
Energy is not to be observed in nature; it does not exist.
What exists in nature is natural force, like a waterfall, or a light, or a fire, or a chemical process.
There we apply the term energy, but energy in itself does not exist, despite the fact that you can buy it at the electrical works.
But that is merely a metaphorical energy.
Energy proper is an abstraction of a physical force, a certain amount of intensity. ~Carl Jung, The Psychology of Kundalini Yoga, Page 7.
For in reality energy is not substantial: it is a conformity of things, say, or the intensity of various physical or material
processes. ~Carl Jung, The Psychology of Kundalini Yoga, Page 8.