Hesperus


In Greek mythology, Hesperus is the Evening Star, the planet Venus in the evening. He is the son of the dawn goddess Eos and is the half-brother of her other son, Phosphorus. Hesperus' Roman equivalent is Vesper. By one account Hesperus' father was Cephalus, a mortal, while Phosphorus' was the star god Astraios. Other sources, however, state that Hesperus was the brother of Atlas, and thus the son of Iapetus.

Variant names

Hesperus is the personification of the "evening star", the planet Venus in the evening. His name is sometimes conflated with the names for his brother, the personification of the planet as the "morning star" Eosphorus or Phosphorus, since they are all personifications of the same planet Venus. "Heosphoros" in the Greek Septuagint and "Lucifer" in Jerome's Latin Vulgate were used to translate the Hebrew "Helel", "son of Shahar " in the Hebrew version of Isaiah 14:12.
There is a tendency to conclude that the ancient Greeks thought that Eosphorus and Hesperos, because of the distinction in the names, were two different celestial objects., that the Greeks only later accepted the Babylonian view that the two were the same, and consequently that it was not Babylonian influence that informed the identification of the planets with the two gods. The Greeks dedicated the "wandering star" to Aphrodite, as the equivalent of Ishtar. This order of influence is not backed by scholars, nor any historical documents. Rather the two mythological explanations seem to have existed simultaneously and interchangeably.
Eosphorus/Hesperus was said to be the father of Ceyx and Daedalion. In some sources, he is also said to be the father of the Hesperides.

"Hesperus is Phosphorus"

In the philosophy of language, "Hesperus is Phosphorus" is a famous sentence in relation to the semantics of proper names. Gottlob Frege used the terms "the evening star" and "the morning star" to illustrate his distinction between sense and reference, and subsequent philosophers changed the example to "Hesperus is Phosphorus" so that it utilized proper names. Saul Kripke used the sentence to posit that the knowledge of something necessary could be empirical rather than knowable a priori.