On Metaphysics (1875-1889)

"A metaphysical conclusion is either a false conclusion or a concealed experimental conclusion." (Hermann von Helmholtz, "On Thought in Medicine", 1877)

“It is true, there could be a metaphysical world; the absolute possibility of it is hardly to be disputed. We behold all things through the human head and cannot cut off this head; while the question nonetheless remains what of the world would still be there if one had cut it off.” (Friedrich Nietzsche, “Human, All Too Human: A Book for Free Spirits”, 1878)

“Logic works, metaphysics contemplates.” (Joseph Joubert, “The Notebooks of Joseph Joubert”, 1883)

“Metaphysics means nothing but an unusually obstinate effort to think clearly.” (William James, “The Principles of Psychology” Vol 1, 1890)

“Metaphysics is the finding of bad reasons for what we believe upon instinct, but to find these reasons is no less an instinct.” (Francis H Bradley, “Appearance and Reality: A Metaphysical Essay”, 1893)

“The history of civilization proves beyond doubt just how sterile the repeated attempts of metaphysics to guess at nature’s laws have been. Instead, there is every reason to believe that when the human intellect ignores reality and concentrates within, it can no longer explain the simplest inner workings of life’s machinery or of the world around us.” (Santiago Ramón y Cajal, "Reglas y Consejos sobre Investigacíon Cientifica: Los tónicos de la voluntad", 1897)