Alchemy is an ancient form of scientific practice in which the alchemist attempts to turn base metals into silver, or gold.
Though it is believed that, as a protoscience, alchemy lent a hand in the advancement of what is modern day chemistry, it was never successful in achieving it’s initial goal of creating noble metals. It is widely known that those that practiced alchemy were hermetics, whose religious and philosophical views included magic and astrology.
Cayea parallels his chemistry, or energy, with this old tradition, claiming it’s of a magical nature and that you should stop hatin' because of it.