وَالْجَرْحُ مُقَدَّمٌ عَلَى التَّعْدِيلِ
As a methodological principle, negative criticism may take precedence over endorsement.
The rationale is that specific, soundly established criticism can disclose a defect unknown to the scholar giving general approval. But the slogan does not mean that every negative remark defeats every positive judgment. Expertise, evidential grounding, and the particular defect must be assessed.
Example: one expert calls a narrator generally reliable while another documents a dated deterioration in memory. This later finding need not erase all previous reliability; it can qualify reports received during the affected period.