“I am very much puzzled to answer you, monsieur,” said M. Sixte after a silence; but the judge began to see that it was useless to use artifice with a man so simple, and he understood that his silence simply showed that he was seeking an exact expression for his thoughts. “I only know the meaning which I myself should attach to this formula, and probably this young man was too well instructed in works of psychology not to think the same. It is evident that in the other sciences of observation, such as physics or chemistry, the counter-verification of any law whatever exacts a positive and concrete application of that law. When I have decomposed water, for example, into its elements, I ought to be able, all conditions being equal, to reconstruct water out of these same elements. That is an experience of the most ordinary kind, but which suffices to summarize the method of the modern sciences. To know by an experimental knowledge is to be able to reproduce at will such or such a phenomenon, by reproducing its conditions.” “Is such a procedure admissible with moral phenomena? I, for my part, believe that it is, and definitely this that we call education is nothing more than a psychological experience more or less well established, since it sums up thus: having given such a phenomenon--which sometimes is called a virtue, such as patience, prudence, sincerity; sometimes an intellectual aptitude, such as a dead or a living language, orthography, calculation--to find the conditions in which this phenomenon produces itself the most easily. But this field is very limited, for if I wished, for instance, the exact conditions of the birth of such passion being once known, to produce at will this passion in a subject, I should immediately come up against insoluble difficulties of law and morals. There will come a time perhaps, when such experiments will be possible. “My opinion is that, for the present, we psychologists must keep to the experiences established by law and by accident. With memoirs, with works of literature or art, with statistics, with law reports, with notes on forensic medicine, we have a world of facts at our service. “Robert Greslon had, in fact, discussed this _desideratum_ of our science with me. I recollect, he regretted that those condemned to death could not be placed in special conditions, which would permit of experimenting upon them certain moral phenomena. This was simply a hypothetical opinion, of a very young mind, who did not consider that, to work usefully in this order of ideas, it is necessary to study one case for a very long time. It would be best to experiment on children, but how could we make any one believe that it would be useful to science to produce in them certain defects or certain vices for example?” “Vices!” exclaimed the judge astounded by the tranquillity with which the philosopher pronounced this phrase.