首楞嚴義疏注經 3.236

3.236

破根生也。初句牒，則諸下舉無五味以問舌根，即無味自甞問也。

This refutes production from the faculty. The first sentence restates it. The words from 'then all' onward present the absence of the five tastes to interrogate the tongue faculty, which is the interrogation of tasting oneself when there is no taste.