“epistemological primitive” (Roederer 1978, 2005), and from there derive the concept of information. We can identify two distinct groups. Category 1) interactions can always be reduced to a linear *superposition* of mutual physical interactions (i.e., forces) between the interacting bodies’ elementary constituents, in which energy transfer between the interacting parts plays a fundamental role. Category 2) interactions cannot be expressed as a superposition of elementary interactions, and it is *patterns and forms* (in space and/or time) that play the determining role on whether or not an interaction is to take place; the required energy must be provided from outside through a specific complex *interaction mechanism*.

Examples of category 1), which we call *force-driven* interactions, are all the physical interactions between elementary particles, wave fields, nuclei, atoms, molecules, parcels of fluid, complex solid bodies and networks, planets and stars. Ultimately, they all originate in the four basic interactions between fundamental particles (electromagnetic, gravitational, strong and weak). It is the fundamental property of reducibility of force-driven interactions, that allows physics to work with approximate *models* of the complex reality “outside” to make quantitative predictions or retrodictions about the time-evolution of a given physical system.

The simplest case of an interaction of category 