وَالنَّظَرِيَّاتُ فَرْعُ الضَّرُورِيَّاتِ
Inferential cognitions are derivative of necessary cognitions.
The dependence is genuine: reasoning begins from premises that must ultimately be known or justified. If every premise required a new proof and that requirement never ended, a conclusion could never be established.
The skeptic goes further: because some immediate judgments can be challenged, all inferential knowledge is allegedly undermined. But particular errors in basic cognition and the universal destruction of basic knowledge are not the same claim.
Unless the foundational category has been defeated wholesale, its derivative category does not fail merely because it depends upon the foundation.