An important part of the concept of the soul in Ancient Egyptian religion was thought to be the heart, or "ib". The "ib" or metaphysical heart was believed to be formed from one drop of blood from the child's mother's heart, taken at conception. To ancient Egyptians, the heart was the seat of emotion, thought, will, and intention. This is evidenced by Egyptian expressions which incorporate the word "ib", such as "Awi-ib" for "happy" (literally, "long of heart"), "Xak-ib" for "estranged" (literally, "truncated of heart"). In Egyptian religion, the heart was the key to the afterlife. It was conceived as surviving death in the nether world, where it gave evidence for, or against, its possessor. It was thought that the heart was examined by Anubis and a variety of deities during the "Weighing of the Heart" ceremony. If the heart weighed more than the feather of Maat, which symbolized the ideal standard of behavior. If the scales balanced, it meant the heart's possessor had lived a just life and could enter the afterlife; if the heart was heavier, it would be devoured by the monster Ammit. The Chinese character for "heart", 心, derives from a comparatively realistic depiction of a heart (indicating the heart chambers) in seal script. The Chinese word "xīn" also takes the metaphorical meanings of "mind", "intention", or "core". In Chinese medicine, the heart is seen as the center of 神 "shén" "spirit, consciousness". The heart is associated with the small intestine, tongue, governs the six organs and five viscera, and belongs to fire in the five elements. The Sanskrit word for heart is "hṛd" or "hṛdaya", found in the oldest surviving Sanskrit text, the Rigveda. In Sanskrit, it may mean both the anatomical object and "mind" or "soul", representing the seat of emotion. "Hrd" may be a cognate of the word for heart in Greek, Latin, and English. Many classical philosophers and scientists, including Aristotle, considered the heart the seat of thought, reason, or emotion, often disregarding the brain as contributing to those functions. The identification of the heart as the seat of emotions in particular is due to the Roman physician Galen, who also located the seat of the passions in the liver, and the seat of reason in the brain.