Meaning: The quote you have provided is from the ancient Greek philosopher Parmenides. Parmenides was a pre-Socratic philosopher who lived in the 5th century B.C. in Elea, a Greek colony in southern Italy. He is considered one of the most significant early Greek philosophers and is known for his work on metaphysics and the nature of reality.

In the quote, Parmenides is discussing the nature of existence and the duality of light and night. He suggests that all things have been named in relation to the concepts of light and night, and that everything is full of both light and invisible night. Parmenides is exploring the idea that the world is composed of opposing forces or principles, and that these forces are in a state of equilibrium, with neither having a greater share than the other.

Parmenides' philosophy is often associated with the concept of "being" and "non-being." He argued that true reality is unchanging and indivisible, and that change and multiplicity are illusory. According to Parmenides, the world of appearances is not true reality, and the senses are unreliable in providing knowledge about the nature of existence. Instead, he believed that reason and logic are the only reliable means of understanding the nature of reality.

The quote reflects Parmenides' belief in the fundamental unity and stability of the universe. He suggests that light and invisible night are equal and present in everything, emphasizing the idea of balance and harmony in the cosmos. Parmenides' philosophy is characterized by its emphasis on the oneness and permanence of being, and his rejection of the idea of a world of change and flux.

In Parmenides' most famous work, "On Nature," he presents a philosophical poem in which he explores the nature of reality and the principles of existence. He presents a cosmology that is based on the idea of a single, unchanging reality, and argues that this reality is timeless and eternal. Parmenides' philosophy had a significant influence on subsequent thinkers, including Plato and Aristotle, and his ideas continue to be the subject of scholarly debate and interpretation.

The quote you have provided encapsulates some of the key themes of Parmenides' philosophy, including the idea of the fundamental unity of the cosmos and the contrast between appearance and true reality. It reflects his belief in the existence of a single, unchanging reality, and his rejection of the world of change and multiplicity. Parmenides' ideas have had a lasting impact on the development of Western philosophy and continue to be studied and debated by scholars and philosophers.