Through the importance of the number three in our culture and the strange preference for a ternary pattern of our nature one can perceive how and why number theory degraded to numerology. The strong preference of our minds for simple patterns can be read as the key to understanding not only the development of numerology, but also why scientists were and are prone to give their discoveries or creations a structure that is based on simple patterns and, among them, especially the ternary pattern. If some numbers seem to appear quite often throughout the fabric of reality, like zero, one, two, and three, reality has, nevertheless, been preferentially analysed in a way to enhance its ternary character. The present excursion through some scientific domains where the ternary pattern has been used tries to offer an answer to the fascination that some numbers, and patterns based on them, exerted and exerts, even today, on human minds. Throughout the overall models created by the human mind, be they natural or spiritual, the models based on a "unary" and on a "dualistic" pattern are surely important, but the model based on a ternary pattern ended up assuming an archetypical character, which is quite intriguing, and deserves to be deepened. The paper is a useful resource for projects for students and background material for teachers of mathematics touching, as it does, on biology, chemistry and physics.