Avicenna on the Method of Inferring ‘Approved Opinions’

‘Approved opinions’ and the method of inferring them are one of the topics that have been briefly discussed in Avicenna’s works. According to him, the intellect alone cannot infer ‘approved opinions’, and other components, such as theoretical opinions, reputation, induction, experience, and expediency, must also play positive roles in inferring them. But the method of inferring ‘approved opinions’ from these different components is a matter of debate: while ‘approved opinions’ fall under the category of conventional premises, and Avicenna talks about substantiating these opinions, there are other places in his work that he speaks of the indemonstrable character of the conventional premises. However, with an analytical look at Avicenna’s discussions in the section on the conventional premises in logic and the functions of practical reason and examining his views on ethics, a new explanation can be provided that clarifies the incompatibility of the aforementioned components with the indemonstrability of conventional premises. This explanation originates from this philosophical point in Avicenna’s work that there is a fundamental difference between substantiation and its premise for inferring the ‘approved opinions’ and demonstration and its premises in classical logic and theoretical philosophy. When he talks about substantiating ‘approved opinions’, Avicenna does not mean to demonstrate them, which is incompatible with his view about the indemonstrability of conventional premises. Contrary to demonstration, substantiation can be based on analogy and induction, that is, ‘approved opinions’ can be inferred analogically and inductively. The analogy can also have different premises, from primary and universal premises to experimental and individual ones. Matters such as manners, passions, and human expediencies can also be included in these premises.