The concept of eternity can be understood in different ways, and it's important to clarify its meaning in the context of discussions about the nature and origin of the universe. In philosophy and theology, eternity often refers to a state that is independent of time or beyond the confines of temporal duration.
When people discuss the idea of an eternal universe, they are not necessarily referring to a universe that has existed for an infinite duration in the past. Instead, they may propose that the universe is timeless or exists beyond the constraints of time altogether.
One philosophical perspective that suggests the possibility of an eternal universe is known as the "block universe" or "eternalism." According to this view, all events in time, past, present, and future, are equally real and exist simultaneously. In this framework, time is often seen as a dimension, similar to the spatial dimensions, and the entire history of the universe is considered as one static block.
From a scientific standpoint, our current understanding of the universe is based on the Big Bang theory, which posits that the universe originated from a singularity around 13.8 billion years ago. However, the question of what occurred before the Big Bang or whether time existed prior to it is a subject of ongoing scientific research and philosophical speculation. Some cosmological models, such as certain versions of the cyclic universe or multiverse theories, propose the existence of an eternal or cyclic process of cosmic creation and destruction.
It's important to recognize that discussions about the eternal nature of the universe can involve complex philosophical and scientific concepts. Different viewpoints and theories exist, and the question of whether the universe is eternal or had a definite beginning is still a topic of investigation and debate among scholars.