It is a common misconception that atheists need to explain who was born on December 25th, 0. However, there are a few key points to clarify:
Atheism is simply the absence of belief in gods or deities. It is not an organized belief system, religion, or worldview. As such, atheists do not collectively adhere to a specific explanation for historical events or dates.
December 25th, 0, is a date that does not exist in historical records. The year 1 AD (Anno Domini) is generally considered to be the year following the traditional birth year of Jesus Christ, although modern scholarship places the estimated year of Jesus' birth around 4 to 6 BC. The exact date of Jesus' birth is unknown and was not recorded in historical accounts.
December 25th was not originally chosen as the birth date of Jesus based on historical evidence but rather as a result of various cultural and religious traditions. Early Christians adopted the date to coincide with existing pagan festivals like Saturnalia and the Roman celebration of the "Birthday of the Unconquered Sun," which took place around the winter solstice. This allowed Christianity to integrate more smoothly into existing practices and increase its acceptance.
Today, Christmas is primarily observed as the celebration of Jesus' birth by Christians. However, people of various religious and non-religious backgrounds also participate in Christmas celebrations as a cultural and festive occasion.
In summary, atheists don't need to explain who was born on December 25th, 0, because that specific date does not correspond to any historical event. Atheism, as a lack of belief in gods, does not inherently address historical dates or religious observances. The choice of December 25th for Christmas is a result of historical and cultural factors and is significant within the context of Christianity, not atheism.