From the analysis of the different functions of our intellect given in the whole of the preceding chapters, it is clear that for a correct use of it, either in a theoretical or a practical reference, the following conditions are demanded: (1.) The correct apprehension through perception of the real things taken into consideration, and of all their essential properties and relations, thus of all _data_. (2.) The construction of correct conceptions out of these; thus the connotation of those properties under correct abstractions, which now become the material of the subsequent thinking. (3.) The comparison of those conceptions both with the perceived object and among themselves, and with the rest of our store of conceptions, so that correct judgments, pertinent to the matter in hand, and fully comprehending and exhausting it, may proceed from them; thus the right _estimation_ of the matter. (4.) The placing together or _combination_ of those judgments as the premisses of _syllogisms_. This may be done very differently according to the choice and arrangement of the judgments, and yet the actual _result_ of the whole operation primarily depends upon it. What is really of importance here is that from among so many possible combinations of those different judgments which have to do with the matter free deliberation should hit upon the very ones which serve the purpose and are decisive. But if in the first function, that is, in the apprehension through perception of the things and relations, any single essential point has been overlooked, the correctness of all the succeeding operations of the mind cannot prevent the result from being false; for there lie the data, the material of the whole investigation. Without the certainty that these are correctly and completely collected, one ought to abstain, in important matters, from any definite decision.