All that kind of thing excites distrust. Having passed all my life in the study of nature, which is always sincere in its manifestations and logical in its processes, it is repugnant to me to turn my thoughts to the investigation of a class of truths, which it seems as if a malevolent and disloyal power was hiding from us with an obstinacy the motive of which we cannot comprehend. In such researches it is not sufficient to employ the ordinary methods of natural philosophy, which are infallible, but very limited in their action. We must have recourse to that other critical method, more subject to error, but more audacious and more powerful, of which police officers and examining magistrates make use when they are trying to bring out a truth in the midst of disagreeing witnesses, a part at least of whom have an interest in hiding that truth. In accordance with these reflections, I cannot say that I am convinced of the reality of the things which are comprised under the ill-chosen name of Spiritualism. But neither do I believe in our right to deny everything; for, in order to have a good basis for denial, it is not sufficient to _suspect_ fraud, it is necessary to _prove it_. These experiments, which I have found very unsatisfactory, other experimenters of great confidence and of established reputation have been able to make in more favorable circumstances. I have not enough presumption to oppose a dogmatic and unwarranted denial to proofs in which scientists of great critical ability, such as MM. Crookes, Wallace, Richet, Oliver Lodge, have found a solid basis of fact and one worthy their examination, to such an extent that they have given to it years of study. And we should deceive ourselves if we believed that men convinced of the truth of Spiritualism are all fanatics. During the experiments of 1892 I had the pleasure of knowing some of these men. I was obliged to admire their sincere desire to know the truth; and I found, in the case of several of them, philosophic ideas very sensible and very profound, joined to a moral character altogether worthy of esteem. That is the reason why it is impossible for me to declare that Spiritualism is a ridiculous absurdity. I ought, then, to abstain from pronouncing any opinion whatever: my mental state on this subject may be defined by the word "agnosticism."