Considered by some to be the greatest philosopher of the 20th century, Ludwig Wittgenstein played a central, if controversial, role in 20th-century analytic philosophy. He continues to influence current philosophical thought in topics as diverse as logic and language, perception and intention, ethics and religion, aesthetics and culture. There are two commonly recognized stages of Wittgenstein's thought—the early and the later—both of which are taken to be pivotal in their respective periods. The early Wittgenstein is epitomized in his Tractatus Logico-Philosophicus. By showing the application of modern logic to metaphysics, via language, he provided new insights into the relations between world, thought and language and thereby into the nature of philosophy. It is the later Wittgenstein, mostly recognized in the Philosophical Investigations, who took the more revolutionary step in critiquing all of traditional philosophy including its climax in his own early work. The nature of his new philosophy is heralded as anti-systematic through and through, yet still conducive to genuine philosophical understanding of traditional problems.