Intelligent Error: It is only too evident that mental effort does not automatically give rise to the perception of the real; the most capable mind may be the vehicle of the grossest error. The paradoxical phenomenon of even a “brilliant” intelligence being the vehicle of error is explained first of all by the possibility of a mental operation that is exclusively “horizontal,” hence lacking all awareness of “vertical” relationships; however, the definition “intelligence” still applies, because there is still a discernment between something essential and something secondary, or between a cause and an effect. A decisive factor in the phenomenon of “intelligent error” is plainly the intervention of an extra-intellectual element, such as sentimentality or passion; the exclusivism of “horizontality” creates a void that the irrational necessarily comes to fill. It should be noted that “horizontality” is not always the negation of the supernatural; it may also be the case of a believer whose intellectual intuition remains latent, this being precisely what constitutes the “obscure merit of faith”; in such a case one may, without absurdity, speak of devotional and moral “verticality.” [GTUFS: RootsHC, On Intelligence]