421. 'To this it must be added that in the spiritual world I have seen those who used such observations in the world to convince themselves in favour of nature reduced to the point of becoming atheists. Their intellect was to be seen in spiritual light open underneath, but closed above, because their thoughts are directed downwards to the earth, and not up to the sky. Above their faculty of sense-perception, which is the lowest part of the intellect, was to be seen a kind of covering. In some cases this flashed with hellish fire, in others it was black as soot, in others still livid like a corpse. So let everyone beware of proofs in favour of nature, and seek proofs in favour of the Divine. There is no lack of material on which to draw.