Now, in obedience to the principle, or maxim, of continuity, that we ought to assume things to be continuous as far as we can, it has been urged that we ought to suppose a continuity between the characters of mind and matter, so that matter would be nothing but mind that had such indurated habits as to cause it to act with a peculiarly high degree of mechanical regularity, or routine. Supposing this to be the case, the reaction between mind and matter would be of no essentially different kind from the action between parts of mind that are in continuous union, and would thus come directly under the great law of mental association, just as the theory last mentioned makes sensation to do. This hypothesis might be called materialistic, since it attributes to mind one of the recognized properties of matter, extension, and attributes to all matter a certain excessively low degree of feeling, together with a certain power of taking habits. But it differs essentially from materialism, in that, instead of supposing mind to be governed by blind mechanical law, it supposes the one original law to be the recognized law of mind, the law of association, of which the laws of matter are regarded as mere special results. This theory has been ridiculed by theologians as the merest whimsey while philosophers have pronounced it to be absurd upon metaphysical grounds; but students of physical and natural science are somewhat more favorable to it. Its advocates maintain that it is a perfectly consistent and legitimate working hypothesis, that it unmistakably commits itself to certain predictions and predesignations, that its truth or falsity ought to be judged exclusively from the comparison of these consequences of it with observation, and that, as far as it has been carried, this comparison has been quite favorable to the theory.