The ancient spiritually achieved ones used alchemical metaphorically for the process of human internal energy transformation. Internal alchemy intends for an individual to transform one's emotion and lower energy to be higher energy and to find the unity of life in order to reach the divine immortality.
God can be realized by a person whose spiritual awareness is equal to the "universal" spiritual awareness.
Alchemy, "the art which had for its main objects the transmuting of the baser metals into gold, the discovery of an elixir of life" is the dictionary definition.
Alchemy is a metaphor to protect the secret practice of meditation.
In Taoism, meditation cultivation is called the "immortal medicine," because it cures all the problems of mankind. The internal alchemy produces a "born again" person, i.e., enlightened, at-onement, an angel on earth (saint).
The process of internal spiritual alchemy turns food into gross physical energy, then gross sexual and physical energy is transformed into mental energy. Mental energy (concentration and awareness) is then changed into spiritual energy in the form of God-Self-Awareness.
In alchemy, which is actually the practice of meditation, the scattered energy (mentality) of the soul (the real inner you) begins to unite and come together.
As the soul (the eternal you) becomes more united and stable, it starts to disassociate and becomes less identified with the physical body.
To make anything pure you must refine it. To refine something you must remove the impurities. To make your SELF pure again you must remove the entanglements to the physical body-brain. Practice meditation to be ye therefore perfect as your (our) heavenly father is perfect.
Internal alchemy, or meditation works the same way as an ELECTRONIC COMPUTER works, i.e., if an electronic computer is turned on and is full of ELECTRIC FORCE but does not move, the screen-saver comes on. The physical body-brain is also a BIO-COMPUTER. In meditation, the body is stilled and the brain is stilled, but, THE SCREEN SAVER THAT APPEARS IS THE ETERNAL SELF. If you touch the electronic computer the screen saver image goes off and the original program will continue, in meditation if the body moves or the memory and visualization function of the brain starts, that is you start to day dream, the screen-saver of ETERNAL SELF disappears. In the case of the human bio-computer the screen saver is NOT a PICTURE, IMAGE or THOUGHT, it is an EXPERIENCE of LIVING CONSCIOUSNESS. The true SELF, the real and eternal SELF will continue. The body temple, body animal or body-brain-computer with its own programs will die, but the spiritual energy of the eternal you never dies. Therefore, meditation IS the practice of SHUTTING DOWN the body-brain computer in order to experience your true and eternal SELF and not the programs of the body-brain-bio machine. Enlightenment is when the living screen saver and your LIVING SPIRITUAL PICTURE are in control and not the incomplete and copied programs of the bio-computer personality. The secret process of separation - the pure (spirit) from the impure (material).