Spencer Heath Archive

Item 70

February 1956

     The three discontinuous and hence measurable elements or aspects of action or events are: Mass or particle, having inertia or force; motion, as length or distance; and time, as succession or rhythm. And the customary dimensional units of these are: the gram, the centimeter and the second. Force times length or times motion is called energy. Force times length alone is called potential energy or work. Force times motion as velocity (length per unit of time) is called kinetic energy. Potential energy is work in contemplation only. Kinetic energy is contemplation of a ratio or rate. Neither can be objectively experienced apart from time. When kinetic energy, a rate of energy or work, is multiplied by time, the product is action. Action is concrete; it differs from energy in that it can not only be imagined; it can also be experienced. Also it is discrete, for it is made up of specific discontinuous events, and particularly of very small events called quanta of action. Quanta of action are uniform in their over-all magnitudes, but not of uniform composition. For the energy in them is variable, in its composition of force and velocity and in its ratio to time. The only respect in which they are uniformly and necessarily the same is in their over-all magnitude, total product of force, velocity and time of which they are composed. For it has been established that every unit of action is the same exceedingly small fraction of what is called an erg-second.