Contains the first volume of a new trilogy of Avicenna's _Physics_ and deals with that part of the _Shifā’_ which concerns physics and natural philosophy, in Latin the _Liber primus naturalium_.

In this book the author intends to present a careful analysis of the Stoic teaching on human action and to apply it to the moral doctrine of mainly Zeno and Chrysippus. The work is divided into two parts: the first deals with the structure of human action, whereas the second applies the result of the performed analysis to the moral theory, especially to the teaching on passions and the ethical evolution of an individual from a pre-moral to a moral stage. (...) In the first chapter the author draws the attention to the Aristotelian background of the Stoic theory: the notion of phantasia, being the faculty which provides images of sensible reality and interprets them, plays an important part in both doctrines. In his analysis of action Aristotle uses logical and linguistic concepts and the Stoics proceed in the same way. According to Zeno, the founder of the Stoic school, human soul comprises eight parts, one of them being the hegemonikon or the mind. Within the mind four powers are distinguished: presentation, assent, impulse and reason; they are enduring and stable entities and they govern the activities corresponding to them. So they exist even when they are not being exercised, they are dispositions of the pneuma of the mind. In spite of their determinism the Stoics were anxious to preserve man's responsibility: therefore they stressed particularly the importance of assent, which causes impulse, whereas impulse produces action. Assent is an internal factor: man is a responsible being because his actions are the result of a personal assent. In this respect man differs from mere animals, which are unable to produce such an act; as a matter of fact assent is not given to a presentation as such, but to the meaning or content of a presentation. Since mere animals are unable to form lekta, they do not have the capacity of performing an act of assent. However mere animals may have something similar, which is called yielding. According to the Stoics no human action is performed without an act of assent, even when the agent is not aware of it: in these cases the assent is implicitly present in the action. This factor does not coincide with the Aristotelian bouleusis: within the Stoic theory of action there is no room for deliberation. The assent is the internal cause of an impulse, which is directed at a predicate, related to an imperative: in this way impulse is the immediate cause of action. (shrink)