How do philosophers define matter? Maybe we could say that matter is made out of fundamental particles. However, that ignores dark matter and energy. But even if we ignore this, What are fundamental particles? They are entirely defined by their mathematical properties such as mass, charge, and spin. So it seems particles are just bundles of these properties. Yet, it seems matter is not just mathematical structure, it feels like there is some "stuff". Are there any books or articles about this topic?