The cardinal signs—Aries (cardinal fire), Cancer (cardinal water), Libra (cardinal air), and Capricorn (cardinal earth)—begin each season, and symbolize activity, initiation, dynamism, speed, executive ability, crisis, self-assertion, and creativity.

All the cardinal signs are self-assertive, but each element in this quadruplicity asserts itself differently. Cardinal fire, Aries, is direct and uncomplicated outward energy; cardinal water, Cancer, is indirect, subjective, and emotionally assertive; cardinal air, Libra, needs unprejudiced action in regard to others and is mentally assertive; and cardinal earth, Capricorn, symbolizes action towards success and social prestige, and is materially oriented in action.

Planets in different cardinal signs are square or opposed to each other, symbolizing friction or discord between their two energies. Isabelle Hickey claims that these particular hard aspects are "faults and unlearned lessons of the previous life." (She is specifically referring to the most recent previous past life here, because she makes this explicit distinction between the three quadruplicities.) Being difficulties between action signs, she goes on to say that "they can be changed by constructive action and, if handled rightly, will not manifest as fixed signs at a later [life] time."