@JTT,
"Normal human reason, although naturally not susceptible of an interpretation universally to be accepted over the whole range of cases likely to arise in jurisprudence, may nevertheless be adequately defined as that state of mind in those neither
non compos mentis, nor of such mental superiority as to be incapable of sharing the thought processes of the majority of persons comprising a reasonably civilised community, in which it is possible for the subject to comprehend the speech, writing, radio-telephonic and television communications, together with the technical terms and processes likely to be encountered in everyday life to the extent that he or she will not suffer any of the direr misfortunes attendant upon a failure of comprehension in these respects."
C.J.Blundell.
An ideal example being someone fluffing up the anti-Catholic claque in order to attract up-thumbs.