EPISTEMOLOGY something as having all the sensible characters of wine, yet being in reality blood, is senseless jargon’ (EWP 146) It is in this context that Peirce first put forward his principle of pragmatism, which he presents as the rule for attaining the maximum clearness about our ideas ‘Consider what effects, that might conceivably have practical bearings, we conceive the object of our conception to have Then, our conception of these effects is the whole of our conception of the object’ (EWP 146) It is important to note that Peirce’s pragmatism is a theory not of truth, but of meaning; and as such it anticipates the verification theory of meaning later put forward by the logical positivists He applies the principle to the concepts of hardness, weight, freedom, and force, and concludes, in the latter case, ‘if we know what the effects of force are, we are acquainted with every fact that is implied in saying that a force exists, and there is nothing more to know’ (EWP 151) In Peirce’s writing it is not always clear how he sees the relationship between logic and psychology At the beginning of his essays to illustrate the logic of science he writes thus: The object of reasoning is to find out, from the consideration of what we already know, something else that we not know Consequently, reasoning is good if it be such as to give a true conclusion from true premises and not otherwise Thus the question of its validity is purely one of fact and not of thinking (EWP 122) On the other hand, Peirce sometimes writes as if logical truths were laws of mental behaviour Thus, having told us that the three main classes of logical inference are deduction, induction, and hypothesis, he goes on to say, ‘In deduction the mind is under the dominion of a habit or association by virtue of which a general idea suggests in each case a corresponding reaction’ (EWP 209) Perhaps the two statements are to be reconciled in this way: reasoning, whether good or bad, is a matter of habit; but it is a matter of fact, not of thought, whether a particular piece of reasoning is valid or not Frege on Logic, Psychology, and Epistemology In the writings of Frege, there is no lack of explicit discrimination between logic and psychology While he was writing his logicist works, from Begriffsschrift onwards, Frege was not interested in epistemology for its own sake, but 155