Logic, to be of any use in the real world, must in some important ways match the reality of the world. So any system of logic assumes a metaphysics. And going t

Logic, to be of any use in the real world, must in some important ways match the reality of the world. So any system of logic assumes a metaphysics. And going the other way, reality must be such as to be able to have creatures who can think logically. This is one instance of a larger principle, namely the inherent mutual interconnectedness of the various areas of philosophy. So for instance, epistemology depends on reality being such that it can be known, and we can know about that reality only the sorts of things that a valid epistemology can determine. Similar mutual relations exist between every two main areas of philosophy. This mutual interconnectedness is a key reason for Neurath's insight that in philosophy you can't tear it all down and change it radically, but only modify it.