Early in his career, Ludwig Wittgenstein adopted Schopenhauer's epistemological idealism, and some traits of Schopenhauer's influence (particularly Schopenhauerian transcendentalism) can be observed in the Tractatus Logico-Philosophicus. However, later on, Wittgenstein rejected epistemological transcendental idealism for Gottlob Frege's conceptual realism. In later years, Wittgenstein became highly dismissive of Schopenhauer, describing him as an ultimately shallow thinker. His friend Bertrand Russell had a low opinion on the philosopher, and even came to attack him in his "History of Western Philosophy" for hypocritically praising asceticism yet not acting upon it.