For every action there is an equal and opposite reaction. Nature is comprised of dualities that seek to always balance each other.
So it is in astrology. The dance of opposing forces is very evident in the progression of the twelve zodiacal signs as well as in the dual nature of opposite signs.
Each sign is a reaction to the previous one: Aries is all bluster and impetuous energy; Taurus is the sign that balances all that impulsiveness by being cautious and patient. Taurus resists change; Gemini pursues it. Gemini is flighty and commitment avoidant; Cancer craves security and familiarity. Cancer wants to mother you and keep you safe at home; Leo asks you to have courage and go out into the world and perform. Leo believes all his of creative impulses must be good; but Virgo will only put her name on something that she has toiled and worried over in an effort to create perfection. Virgo needs solitude; Libra wilts when alone. Libra avoids conflict and exploring the darker impulse of his nature; Scorpio is relentless in his examination of his darker side (and everyone elses’ too.) Scorpio is secretive and guarded; Sagittarius is an open book. Saggy is an optimist and a dilettante; Capricorn is focused and tends to depression. Capricorn wants to create institutions and gain personal power within them; Aquarius wants to destroy the social norms and wants everyone to share the power equally. Aquarius is mystified by his feelings and values reason above all else; Pisces lives in his feelings and sees where reason is limited. Pisces would like to meditate all day; Aries can’t sit still. And so it goes.
Astrologers have written about these dynamics before and in much greater depth than I have here. But the point has been made about the duality we see everywhere in nature. Not only do the successive signs participate in this dance of duality, but so do opposite signs. Opposite signs are like two sides of the same coin and have common essence and remarkable similarities in addition to their obvious contrasts.
Aries and Libra are both cardinal, proactive signs and will fight for fairness.
The fixed signs of Taurus and Scorpio both value productivity and have great determination.
The mutable signs of Gemini and Sagittarius share restlessness, curiosity and mental energy.
Cancer and Capricorn are security conscious and capable of great focus.
Leo and Aquarius offer leadership especially with the welfare and education of youth and the future of mankind.
Virgo and Pisces ask us to examine our values, our methods and our motives to prepare us for a higher, better expression of ourselves by surrendering that which holds us back.