This seems pretty plausible to our modern generation raised in the traditions of nominalism, but would we really ignore the law of gravitation because the Newtonian formula is a man-made abstraction and a mere generalization? Yet, if we do not give heed to it we fall, and the same is true of any law of nature. Our sciences are mental constructions; they are mind-made, and so far as they are built out of the material of our experience they tally with facts and we call them true. Our social interrelations, too, constitute conditions observable in experience; they can be formulated in Jaws and applied to practical life; they can be expressed in maxims of conduct and have received various sanctions successively, the sanctions of religion, the sanctions of metaphysics, the sanctions of science. In the age of savagery the sanction of moral maxims was offered us in a mythological dress. With the rise of monotheism our moral sanction came to us as the command of a supreme ruler of the universe; in the age of abstract philosophy as metaphysical principles, and in the age of science these should be recognized as lessons of experience. [1] May 13, 1809. Detroit, 949 Gratiot Ave. CONCLUSION. We will gladly grant that personifications are mythological fictions, that metaphysical entities are products of a philosophical imagination and that the scientific formulas are abstract generalizations, but we deny that generalizations are unmeaning; they signify some actual features of reality. Abstract ideas are not purely fictitious; they denote significant qualities or occurrences, and the relations in life, the forms of things, combinations, or in general the non-material configurations, co-operations, combinations and functions are the most important and the most significant aspects of existence. Indeed, matter and energy are only the clumsy conditions of being; they denote actuality and reality, but all things, all events, all facts are such as they are on account of their form--on account of that feature which is non-material and non-energetic.