"This Principle embodies the truth that "everything is dual"; "everything has two poles"; "everything has its pair of opposites," all of which were old Hermetic axioms. It explains the old paradoxes, that have perplexed so many, which have been stated as follows: "Thesis and antithesis are identical in nature, but different in degree"; "opposites are the same, differing only in degree"; "the pairs of opposites may be reconciled"; "extremes meet"; "everything is and isn't, at the same time"; "every truth is half-false"; "there are two sides to everything," etc., etc., etc. It explains that in everything there are two poles, or opposite aspects, and that "opposites" are really only the two extremes of the same thing, with many varying degrees between them. To illustrate: Heat and Cold, although "opposites," are really the same thing, the differences consisting merely of degrees of the same thing. Look at your thermometer and see if you can discover where "heat" terminates and "cold" begins! There is no such thing as "absolute heat" or "absolute cold" - the two terms "heat" and "cold" simply indicate varying degrees of the same thing, and that "same thing" which manifests as "heat" and "cold" is merely a form, variety, and rate of Vibration. So "heat" and "cold" are simply the "two poles" of that which we call "Heat" - and the phenomena attendant thereupon are manifestations of the Principle of Polarity. The same Principle manifests in the case of "Light and Darkness," which are the same thing, the difference consisting of varying degrees between the two poles of the phenomena. Where does "darkness" leave off, and "light" begin? What is the difference between "Large and Small"? Between "Hard and Soft"? Between "Black and White"? Between "Sharp and Dull"? Between "Noise and Quiet"? Between "High and Low"? Between "Positive and Negative"? The Principle of Polarity explains these paradoxes, and no other Principle can supersede it. The same Principle operates on the Mental Plane. Let us take a radical and extreme example that of "Love and Hate," two mental states apparently totally different. And yet there are degrees of Hate and degrees of Love, and a middle point in which we use the terms "Like or Dislike," which shade into each other so gradually that sometimes we are at a loss to know whether we "Like" or "dislike" or "neither." And all are simply degrees of the same thing, as you will see if you will but think a moment. And, more than this (and considered of more importance by the Hermetists), it is possible to change the vibrations of Hate to the vibrations of Love, in one's own mind, and in the minds of others. Many of you, who read these lines, have had personal experiences of the involuntary rapid transition from Love to Hate, and the reverse, in your own case and that of others. And you will therefore realize the possibility of this being accomplished by the use of the Will, by means of the Hermetic formulas. "Good and Evil" are but the poles of the same thing, and the Hermetist understand the art of transmuting Evil into Good, by means of an application of the Principle of Polarity. In short, the "Art of Polarization" becomes a phase of "Mental Alchemy" known and practiced by the ancient and modern Hermetic Masters. An understanding of the Principle will enable one to change his own Polarity, as well as that of others, if he will devote the time and study necessary to master the art." (The Kybalion; San Francisco, 1904)
This principle has been known since antiquity. It has been and is depicted in the symbols of many belief systems. These symbols include but are not limited to the circle, cross, Star of David, Yin/Yang and Eagle Feather.
This is a table of seeming opposing states, conditions, motions or vectors. For dualities of state, condition or cause and effect see Table of Cause and Effect Dualities. [See Celestial and Terrestrial Domains]