What are the symbols of duality in Freemasonry?

The mosaic pavement features parti-colored stones of black and white, which are interpreted as symbols of the evil and good of human life 1. Derived from ancient Mosaic symbolism, the floor of the lodge thus represents the dualities and moral contrasts encountered throughout human existence 1.

Duality is likewise expressed through the twin brazen pillars situated at the porch of King Solomon's Temple 2. Various Masonic writers have offered distinct dualistic interpretations for these columns 2. Some suggest they represent the masculine and feminine elements in nature, while others view them as symbols for the dual authorities of Church and State, recalling occasions when the high priest stood before one pillar and the king before the other 2. William Preston saw in them a reference to the pillars of cloud and fire that guided the Israelites through the wilderness 2. Beyond these paired readings, the twin columns collectively symbolize divine strength and stability 2.