That is...

That is, regarding evil, there must be a subject with an existential quality such that its desirability must be assumed and the absence of this quality of desirability from it would be regarded as “evil”. For instance, the human being’s possession of eyes is good. (Naturally, he wants to have eyes and it is also possible for him not to have them.) On the contrary, blindness is treated as “evil” for him.

And as a conclusion of this examination, we arrive at the point that “evil” – wherever it is – first and foremost, is a non-existential ( ‘adamī ), and secondly, a potential ( imkānī ) matter.[^2] To elaborate, physical existents are constituted by [certain] abilities and potentials, and they gradually acquire the existential perfections which may be possible for them.

This gradual development depends on the mutual interaction among the physical existents, for each of the natural species has peculiar defects and perfections which are acquired through many other natural phenomena, and it is here that a sort of clash or conflict arises, and as a result, relative or subjective evil comes into being.

In other words, the ability of matter to assume various forms, on one hand, and the contradiction of one form with another, on the other hand, are an element of destruction as well as construction, an agency for both extinction and origination, [an instrument of] wiping out the past as well as building the future, [a means of] taking out old forms and images and bringing out new portraits.

As long as the members and elements do not clash with each other and do not influence each other, no average disposition or new combination will emerge.

Thus, it is correct for us to say that “Contradiction is the source of good and the balancer of the universe, and the order in the universe is based on it.”[^3] In a discussion on the manner of involvement of evil in the Divine decree, Ṣadr al-Muta’allihīn has thus said: “The materialization of non-finite beings or existents which necessitates the Divine providence necessitates the existence of transubstantiation ( istiḥālāh ) and contradiction ( taḍād ) in the world of generation and corruption ( ‘ālam-e kawn wa fasād or the realm of nature), for without contradiction, generation and corruption will not be materialized, and without generation and corruption, in turn, non-finite animal and human existents and beings would not have existed.