A Beneficial Note
Knowledge is the transfer of the form of the thing known from the external world and its establishment within the soul, whereas action is the transfer of a practical form from the soul and its establishment in the external world. (1)

If what is fixed in the soul corresponds to the reality of the thing itself, the knowledge is sound. Yet images often settle and appear in the soul that have no real existence; the person who has imprinted them assumes them to be knowledge, while in truth they are mere fancies with no substance. Most people’s “knowledge” belongs to this category.

Of the notions that do match external reality, there are two kinds:

1. A kind through which the soul is perfected by perceiving and knowing it—namely, knowledge of Allah, His Names, Attributes, acts, scriptures, commands, and prohibitions.
2. A kind that brings no perfection to the soul: every field of knowledge whose absence causes no harm, for knowing it yields no benefit. The Prophet ﷺ used to seek refuge with Allah from knowledge that does not benefit. (2) Such is the case with most correct, reality-based sciences whose ignorance does not detract in the least—for example, detailed astronomy, its subtleties and degrees, the number of stars and their measurements, or the tally, colors, and dimensions of mountains, and the like.

Thus, the nobility of any science is measured by the nobility of its subject matter and by how greatly one stands in need of it—and that standard is met only by the knowledge of Allah and all that follows from it.