What legal rule is shared by ẓāhir and naṣṣ?

Degrees of Indication: Ẓāhir, Naṣṣ, Mufassar, Muḥkam and Obscure Expressions

• Act on each unless a valid contrary proof is established
• Both must always be suspended because alternatives exist
• Naṣṣ must always be set aside for ẓāhir
• Only naṣṣ is probative; ẓāhir never is