67

Logic 67 On how we think

6th Other authors indeed a large majority of logician without citing results of scientific psycology in support of the principles of logic yet incessantly refer to data of psychology or to what would ordinarily be so considered apparent self-obsevations that we think so and so as showing what the truths logic are.
All this is beside the purpose.
Logic is not the science of how we do think but in such sense as it can be said to deal with thinking ar all it only determines how we ought to think nor how we ought to think in conforming with usage but how we ought to think in order to think what is true.
That a premiss should be pertinent to such a conclusion it is requisita that it should relate not to how we think but to the necessary connections of different sort of fact.