Philosophy of Arithmetic: Psychological and Logical Investigations (German: Philosophie der Arithmetik. Psychologische und logische untersuchungen) is an 1891 book about the philosophy of mathematics by the philosopher Edmund Husserl. Husserl's first published book, it is a synthesis of his studies in mathematics, under Karl Weierstrass, with his studies in philosophy and psychology, under Franz Brentano, to whom it is dedicated, and Carl Stumpf. Source: Wikipedia (en)