Theory is derived from the earlier proven formulae. In sanskrit language, there are two aspects - 'samanya' and 'visesha'. Samanya is what we see once and again. For example, this crow is black, that crow is black, the other crow is black. So theory is derived as 'every crow is black'. Of-co0urse there are exceptions and some one may claim that he has seen a white crow. But, the wise knows that it means not the crow of which we proved about.
Same way, One theory that was not proved to its extremity or entirety, but 91.6% true and proved, could be applicable in psychology on the risk that more than certain percentage it would be useful.
Thus the most experienced Medical Officer advises "to take this tablet or capsule for 5 course and let me know the result" to escape from the promise of 100% recovery of the patient.
A 1998 false-colour near-infrared image of Uranus showing cloud bands, rings, and moons obtained by
False-color imagery of the Sun, a G-type main-sequence star, the closest to Earth.
Comparison of Major developmental theories
psychology perception
Major Events in the History of Psychology
Where Professional Psychologists Work Primary employment settings for PhD recipients in psychology.