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CP 2.120. If this be so, and if the scheme of classification of the sciences that has been proposed be correct, it will follow that there are but five theoretical sciences which do not more or less depend upon the science of logic. One of these five is Logic itself, which must contrive, by hook or by crook, to work out its own salvation without a full pre-acquaintance with its own discoveries, but which, like any other science, will lay one stone upon another in the erection of its doctrine. This is the last of the five. The first is Mathematics. Mathematics may itself be regarded as an art of reasoning. Perhaps this is not the highest conception of it. But at any rate, mathematics has no occasion to inquire into the theory of the validity of its own argumentations; for these are more evident than any such theory could be. The second of the five is that department of philosophy called Phenomenology, whose business it is simply to draw up an inventory of appearances without going into any investigation of their truth. The third is Esthetics, if I am to take the word of others that there is such a science, I myself being lamentably ignorant of it, as I fear will too plainly appear. The fourth is Ethics; certainly, one of the very subtlest of studies. The whole course of it seems to consist in painfully extricating oneself from one pitfall only straightway to fall into another. It might seem that logic was desirable in this deliberation; but I fear that logic, as a definite theory, can be of no avail until one knows what it is that one is trying to do, which is precisely what ethics has to determine. On the contrary, that has to be settled before one can form any sound system of logic, as we shall see in due time.
CP 2.121. All the other sciences but those five, according to the principles herein to be defended, depend upon Logic. I do not mean merely that they practice logical reasoning: they draw principles from the theory of logic. This dependence will be most direct and intimate for those sciences which stand nearest after Logic in the scheme of the sciences; yet even those which are most remote, such as History on the Psychical side, and Geology on the Physical side, have sometimes to make direct appeal to the theory of evidence. Besides that, all these Descriptive sciences must be founded upon Classificatory Sciences. Now that the classificatory sciences have to make appeal to the science of rationality, and always have done so, in order to determine what they are to think of the reality of their own classifications, will not be denied. Moreover, the Classificatory Sciences are and must be founded upon the Nomological Sciences. Here we find the psychologists, on the one side, together with Galileo, Kepler, Newton, Descartes, and all the founders of nomological physics, on the other, making direct appeal to the theory of logic. In addition to that, these Nomological Sciences cannot avoid depending upon Metaphysics. It is when they promise themselves that they will not make any metaphysical assumptions that they are most in danger of slipping too deep into the metaphysical slough for deliverance, precisely because one cannot exercise control and criticism of what one does unconsciously. At a later stage of our logical studies this dependence of nomology upon metaphysics will appear very evident. As to Metaphysics, if the theory of logic which is to be developed in this book has any truth, the position of the two greatest of all metaphysicians, Aristotle and Kant, will herein be supported by satisfactory proof, that that science can only rest directly upon the theory of logic. Indeed, it may be said that there has hardly been a metaphysician of the first rank who has not made logic his stepping-stone to metaphysics. END
At the risk of repeating things, I feel this hefty chunk of CP is useful because it underlines the clear direction of Peirce -- and his clear modernity. Nomological refers to considerations that do not have the status of fixed law and whose veracity requires conformity with reason and logic.
CP 2.121. All the other sciences but those five, according to the principles herein to be defended, depend upon Logic. I do not mean merely that they practice logical reasoning: they draw principles from the theory of logic. This dependence will be most direct and intimate for those sciences which stand nearest after Logic in the scheme of the sciences; yet even those which are most remote, such as History on the Psychical side, and Geology on the Physical side, have sometimes to make direct appeal to the theory of evidence. Besides that, all these Descriptive sciences must be founded upon Classificatory Sciences. Now that the classificatory sciences have to make appeal to the science of rationality, and always have done so, in order to determine what they are to think of the reality of their own classifications, will not be denied. Moreover, the Classificatory Sciences are and must be founded upon the Nomological Sciences. Here we find the psychologists, on the one side, together with Galileo, Kepler, Newton, Descartes, and all the founders of nomological physics, on the other, making direct appeal to the theory of logic. In addition to that, these Nomological Sciences cannot avoid depending upon Metaphysics. It is when they promise themselves that they will not make any metaphysical assumptions that they are most in danger of slipping too deep into the metaphysical slough for deliverance, precisely because one cannot exercise control and criticism of what one does unconsciously. At a later stage of our logical studies this dependence of nomology upon metaphysics will appear very evident. As to Metaphysics, if the theory of logic which is to be developed in this book has any truth, the position of the two greatest of all metaphysicians, Aristotle and Kant, will herein be supported by satisfactory proof, that that science can only rest directly upon the theory of logic. Indeed, it may be said that there has hardly been a metaphysician of the first rank who has not made logic his stepping-stone to metaphysics. END
At the risk of repeating things, I feel this hefty chunk of CP is useful because it underlines the clear direction of Peirce -- and his clear modernity. Nomological refers to considerations that do not have the status of fixed law and whose veracity requires conformity with reason and logic.
