Cycles theories have emerged in a number of scientific disciplines. In biology, Wilhelm fliess theorized that two cycles governed living cells. In men the male cycle of 23 days was dominant; in women the dominant female cycle was 28 days. These cycles affected every¬ thing from birth to death, physical and mental health, career prospects, sex, life, and so on. In his major work The Rhythm of Fife: Foundations of an Exact Biology (1923), Fliess advances a formula to explain how these two cycles combine to impose various compound cycles: (23x + 28y), in which x and y can be positive or negative integers. So the familiar 28-day menstrual cycle has x = 0 and y = 1. If x is 4 and y is 11 the sum is 365 days, another familiar cycle. What had escaped his attention is that x and y can be selected to give every number from 1 to as high as you have the patience to calculate. A theory which contains everything explains nothing.
In the late 20th century, Biorhythms were held to influence or control human lives. A third cycle was added to the original pair: the intellectual cycle of 33 days. The male cycle governs physical strength and endurance and what are held to be masculine attitudes; the female cycle governs the feminine virtues of nurturing, sensitivity, and mental alertness; and the intellectual cycle governs mental capabilities. People are advised to adjust their actions to these cycles.