Avicenna and Thomas Aquinas understand animal intelligence in reference to the activity of vis aestimativa, through which they explain animal behaviour as being consequent to an apprehensive appraisal of its environment. This apraisal must be distinguished from the representative knowledge of the phantasma, because it is not of per se sensed qualities, but per accidens, that Avicenna calls intentiones. Explaining animal behaviour from the vis aestimativa allows to understand it without attributing it to intelligence, which has been classically considered to be exclusive of rational beings’ conceptual knowledge of reality.
Contemporary explanations in Psychology of Emotions lack reference to the Aristotelian notion of nature. Subsequently, from this stance it is impossible to understand emotions as tendencies. This and some other deficiencies of contemporary Psychology, such as the confusion between emotion and cognition, are rooted in its Cartesian basis in this field. The present article will try to revalue the concept of nature as key to formally distinguish different psychological operations and to understand their dynamism and proper order in human beings.