Reasoning has the same effect upon a suggested solution as more intimate and extensive observation has upon the original problem. Acceptance of the suggestion in its first form is prevented by looking into it more thoroughly. Conjectures that seem plausible at first sight are often found unfit or even absurd when their full consequences are traced out. Even when reasoning out the bearings of a supposition does not lead to rejection, it develops the idea into a form in which it is more apposite to the problem. Only when, for example, the conjecture that a pole was an index-pole had been thought out into its bearings could its particular applicability to the case in hand be judged. Suggestions at first seemingly remote and wild are frequently so transformed by being elaborated into what follows from them as to become apt and fruitful. The development of an idea through reasoning helps at least to supply the intervening or intermediate terms that link together into a consistent whole apparently discrepant extremes (_ante_, p. 72). [Sidenote: 5. Corroboration of an idea and formation of a concluding belief] 5. The concluding and conclusive step is some kind of _experimental corroboration_, or verification, of the conjectural idea. Reasoning shows that _if_ the idea be adopted, certain consequences follow. So far the conclusion is hypothetical or conditional. If we look and find present all the conditions demanded by the theory, and if we find the characteristic traits called for by rival alternatives to be lacking, the tendency to believe, to accept, is almost irresistible. Sometimes direct observation furnishes corroboration, as in the case of the pole on the boat. In other cases, as in that of the bubbles, experiment is required; that is, _conditions are deliberately arranged in accord with the requirements of an idea or hypothesis to see if the results theoretically indicated by the idea actually occur_. If it is found that the experimental results agree with the theoretical, or rationally deduced, results, and if there is reason to believe that _only_ the conditions in question would yield such results, the confirmation is so strong as to induce a conclusion--at least until contrary facts shall indicate the advisability of its revision. [Sidenote: Thinking comes between observations at the beginning and at the end]