In philosophy of science, a paradigm is a way of thinking about a problem. The word comes from Greek παράδειγμα ("paradeigma"), "pattern, example, sample" from the verb παραδείκνυμι ("paradeiknumi"), "exhibit, represent, expose" and that from παρά ("para"), "beside, beyond" and δείκνυμι ("deiknumi"), "to show, to point out". Paradigm can also be used to refer to a set of ideas about a given subject. The idea that the Earth is the center of the universe, or that the Earth and other planets move around the sun are examples of paradigms. One of the first modern people to use the word was Georg Christoph Lichtenberg (1742-1799), an 18th century mathematician and scientist.