I have myself witnessed or been a party to a case of the following kind:--A new truth--suppose for example, a new doctrine or a new theory--was communicated to a very able man in the course of conversation, not _didactically_, or directly _as_ a new truth, but _polemically_,--communicated as an argument in the current of a dispute. What followed? Necessarily it followed that a very able man would not be purely _passive_ in receiving this new truth; that he would _co-operate_ with the communicator in many ways--as by raising objections, by half dissipating his own objections, and in a variety of other co-agencies. In such cases, a very clever man does in effect half-generate the new idea for himself, but then he does this entirely under your leading; you stand ready at each point of possible deviation, to warn him away from the wrong turn--from the turn which leads nowhither or the turn which leads astray. Yet the final result has been that the _catechumen_, under the full consciousness of _self_-exertion, has so far confounded his just and true belief of having contributed to the evolution of the doctrine, _quoad_ his own apprehension of it, with the far different case of having evolved the truth itself into light, as to go off with the firm impression that the doctrine had been a product of his own.[24] There is therefore ground enough for the jealousy of Adam Smith, since a robbery may be committed unconsciously; though, by the way, it is not a peril peculiarly applicable to himself, who has not so much succeeded in discovering new truths as in establishing a logical connexion amongst old ones. [24] For a similar passage, see _ante_, pp. 96, 97.--M.