The central question of the meaning of life is often phrased as 'What is the purpose of existence?' or 'Why are we here?'.

Socrates is known for his existentialist ideas on the meaning of life, which emphasize the importance of self-knowledge and ethical living.

Eudaimonia is a Greek term that is often translated as 'happiness' or 'well-being'. It is a central concept in ancient Greek philosophy, particularly in the works of Aristotle.

Epicurus is known for his hedonistic philosophy, which argues that the meaning of life is to seek pleasure and avoid pain.

Angst or dread is an existentialist concept that refers to a feeling of anxiety or unease about the meaninglessness of life.

Friedrich Nietzsche is known for his existentialist philosophy, which emphasizes the importance of creating one's own values and living authentically.

Absurdism is an existentialist concept that refers to the belief that life is inherently meaningless and that humans are unable to find ultimate meaning or purpose in their existence.

Bertrand Russell is known for his book 'The Meaning of Life', in which he explores the question of the meaning of life from a philosophical perspective.

Existential authenticity refers to the concept of living in accordance with one's true self, rather than conforming to societal expectations or norms.

Epictetus is known for his Stoic philosophy, which emphasizes the importance of finding joy in the present moment and accepting the things that we cannot change.

Logotherapy is a therapy that focuses on helping people find meaning in their lives and overcome existential anxiety.

Socrates is known for his famous quote, 'The unexamined life is not worth living', which emphasizes the importance of self-reflection and ethical living.

Theodicy is the attempt to justify the existence of evil in a world created by a benevolent and omnipotent God.

John Stuart Mill is known for his utilitarian philosophy, which argues that the meaning of life is to create a better world for future generations by maximizing happiness and minimizing suffering.

Existential nihilism is the belief that life is inherently meaningless and that there is no objective meaning or purpose to human existence.