1. It would be a mistake to think that witnessing a few extraordinary phenomena would be enough for certain disbelievers to be convinced. Those who cannot believe in a soul or spirit in the human being cannot believe in it outside the human being either. Consequently, by denying the cause, they deny the effect. Hence, they nearly always come with a preconceived idea and a negative stance that keeps them from making a serious and impartial observation. They ask questions and raise objections to which it is impossible to immediately respond completely, because it would be necessary to give a sort of course and to start from the beginning for each individual. The result of prior study is that it can respond beforehand to objections, the majority of which are founded on the ignorance of the cause behind the phenomena and the conditions in which they are produced.