Luwig Josef Johann Wittgenstein (pronounced [ˈluːtvɪç ˈjoːzɛf ˈjoːhan ˈvɪtgənʃtaɪn] in German) (April 26, 1889 – April 29, 1951) was an Austrian philosopher who worked primarily in the foundations of logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language. His influence has been wide-ranging and he is generally regarded as one of the twentieth century's most important philosophers.