In ancient times, such as with the Ancient Greeks, the aesthetics of music explored the mathematical and cosmological dimensions of rhythmic and harmonic organization. In the 18th century, focus shifted to the experience of hearing music, and thus to questions about its beauty and human enjoyment ("plaisir" and "jouissance") of music. The origin of this philosophic shift is sometimes attributed to Alexander Gottlieb Baumgarten in the 18th century, followed by Immanuel Kant. Through their writing, the ancient term 'aesthetics', meaning sensory perception, received its present-day connotation. In the 2000s, philosophers have tended to emphasize issues besides beauty and enjoyment. For example, music's capacity to express emotion has been a central issue.