The Commens Dictionary
Quote from ‘That Categorical and Hypothetical Propositions are one in essence, with some connected matters’
There are […] observations which are not only open to all men; but which are necessarily open to all intelligences capable of acquiring scientific, imperfect knowledge from observation and reasoning. The science which is base on such observations as these may suitably be called philosophy. This science will be somewhat narrower than what is commonly called philosophy, since it will exclude ethics, esthetics, etc. which repose on observations which might be foreign to some kind of scientific mind. This science of philosophy, although it is observational, yet will have, in a certain sense, a necessary character; for it is based exclusively on such observations as must be open to every scientific intelligence.
MS [R] 787:5
‘Philosophy’ (pub. 26.05.15-13:27). Quote in M. Bergman & S. Paavola (Eds.), The Commens Dictionary: Peirce's Terms in His Own Words. New Edition. Retrieved from http://www.commens.org/dictionary/entry/quote-categorical-and-hypothetical-propositions-are-one-essence-some-connected-3.