The paradigm of physics suggests that phenomenal laws can be gained through experiment, instrumentation (measurement), and calculation. But of these three paths only calculation is available to psychology.[9]  Calculation alone can reveal the basic laws and concepts of the psyche; psychic phenomena are then to be traced back or “reduced” to these rules; and in this way an “interconnected order” of the psychic manifold may be constructed, analogous to the one physics provides to external, sensible phenomena. As he puts it in “On Analogies, with Respect to the Foundation of Psychology”, 