327. Following these events I said to the people standing by, "From the evidence of these three experiments you now see what the difference is between something spiritual and something natural; and also the reason why a natural person is not visible to a spiritual one, nor a spiritual person to a natural one - even though they are affiliated in respect to their affections and thoughts and so in respect to their presence. That, Headmaster, is why one moment you would see me on the way, and the next moment not." After that we heard a voice from the higher heaven saying to the headmaster, "Come up here." So he went up. And when he returned he said that like himself, the angels had not known before the differences that exist between something spiritual and something natural, owing to the fact that they had not previously been given an opportunity to contrast them in the case of a person who was at the same time in both worlds; and without the contrast these differences are not known.