امتناع الاختلاف إنما هو في الماهية الحقيقية
The prohibition against such variation concerns real essence.
The discussion distinguishes components of a thing's actual essence from a composite meaning formed in understanding. An intelligible composite may involve differences of strength, degree or condition without implying that every essential constituent of a real kind changes.
Consequently, “the feature is internal” must not be overextended into an unqualified scientific claim about all objects. Its import depends on the concept selected for rhetorical analysis and the respect in which its elements are being compared.