«وَكَانَ مُسْتَنَدُ انْتِهَائِهِمُ الْحِسَّ»
The ultimate basis of what they report must be sense perception.
Hiss refers here to relevant perception, such as witnessing an event or directly hearing an utterance. Numerous independent witnesses to a publicly observed occurrence illustrate this requirement.
By contrast, the agreement of many people about a speculative philosophical conclusion does not become sensory transmission merely because the number of supporters grows. Reports grounded in observed events and agreement on inferred propositions are different epistemic situations.