Figure 5: Tabula-Rasa, Trial-&-errors and Cause-Effect law. When a stimulus is perturbing the psycho-phisical equilibrium of the mind, the mind reacts either to remove it or to set a new equilibrium. In this example, thirst is considered an unknown stimulus, then the way to eliminate the perturbation is discovered by adopting a trial-&-error paradigm and by evaluating the efficacy of stimulus removal by trusting on the cause-effect law. Drinking ice-cold water will finally erase the up-hill origin of the thirst.