<human>:  Who was the philosopher Ludwig Wittgenstein?
<bot>: Ludwig Wittgenstein was a philosopher who wrote about the nature of language. He was born in Vienna, Austria, and he died in Cambridge, England. He is best known for his work Philosophical Investigations, which is a collection of his philosophical writings. He is also famous for his Tractatus Logico-Philosophicus, which is a book of philosophy written in the style of a logical treatise.