among the meanings that are not apprehended by sense perception or imagination. Its love or hatred for the subject in which such a meaning inheres then follows from its love or hatred for that meaning. Thus, when a sheep apprehends in a wolf a power incompatible with itself, it hates the wolf; and when a he-goat apprehends in a sheep a power congenial to itself, it loves the sheep. This faculty apprehends lovable and hateful meanings inhering in perceptible things. It is also the faculty through which hope and fear arise: the animal hopes for what it loves to occur and fears the occurrence of what it hates. This is why they associated hope and fear with this faculty, as their statements quoted earlier show, and made its perfection consist in assuming the form of what it hopes for or remembers.

They said that a person’s fear of the dead and the like arises through this faculty. Accordingly, every instance of love, hatred, hope, or fear directed toward something an animal has not perceived through its external senses arises through this faculty.

[Ibn Sīnā’s discussion of the estimative faculty in al-Shifā (The Healing)]

For this reason, they accorded it great importance. Ibn Sīnā said in his al-Shifā, concerning the faculty called estimation:

“It is the governing faculty that judges in an animal. Its judgment is not decisive like rational judgment, but rather an imaginative judgment tied to particularity and sensory form. From it proceed most animal actions.”