Al-Āmidī himself has explained the falsity of the claim that substances are alike.
Among the things that should be understood in questions such as these are disputes over wording. If someone says, “Specification requires a specifying agent, and determination requires a determining agent,” this is like saying, “Setting something in motion requires an agent who sets it in motion,” and similar statements. There is no doubt about this. For takhsīs (“specification”) is the verbal noun of khassasa, yukhassisu (“to specify”); the same applies to determination, speaking, and the like. The verbal noun of a transitive verb necessarily requires an agent whose action extends to an object. To posit such a verbal noun without an agent whose action extends to an object would therefore be contradictory.
This differs from saying, “Having a particular character requires a specifying agent, and a magnitude requires a determining agent,” and similar statements. Nothing in the wording establishes this, since what is mentioned is either the verbal noun of an intransitive verb, such as ikhtisās (“having a particular character”), or a noun that is not a verbal noun, such as “magnitude.” Neither expression contains anything that necessitates its dependence on an agent whose action extends to it.
Thus, if someone says, “The entity possessing an attribute and a magnitude has a particular attribute and magnitude, so it must have a specifying agent,” nothing in this statement establishes its dependence on a specifying agent distinct from itself that specifies it in this way. By contrast, saying, “If it has been assigned an attribute or a magnitude, then it must have an agent who assigns it,” is correct.
Those who engage in theoretical inquiry, and others, may not observe such distinctions when they are concerned with meanings. Rather, they apply a passive participle to something that is not known to have an agent acting upon it. One of them will say, “This is specified by this attribute and magnitude, and whatever is specified must have a specifying agent.” If “specified” is understood as a passive participle, then it is clear that it