Paradigm is a conceptual position about something such as phenomenon. The phenomenon may be natural and man-made. For instance, in astronomy geocentric and heliocentric are two fundamentally different and diametrically opposite paradigms about relative positions of earth and sun. Evolving human minds constantly struggle to find out new paradigms to explain natural or man-made phenomenon such as technology. Newton's laws of motion, Galileo's laws pertaining to pendulum are two paradigmatic views of motion. Once a paradigm is widely accepted and it becomes a standard for practice and behavior. The occasional arrival of new paradigm invalidates the assumption of older paradigms and takes much more time for wider acceptance and practice. The valid assumptions of old paradigms continued to be practiced under new and changed atmosphere out of habit. This prevents total harnessing of new possibility. Such paradigms that have past their time and are no more valid or partially useful are called Paradigms of the past. I shall be listing and discussing some them elsewhere.