Short answers, pulled from the story.
The first English use of the phrase "meaning of life" appears in Thomas Carlyle's Sartor Resartus, published between 1833 and 1834, in book II, chapter IX, titled "The Everlasting Yea". Carlyle may have been inspired by the equivalent German phrase der Sinn des Lebens, used earlier by Romantic writers Novalis and Friedrich Schlegel.
Arthur Schopenhauer was the first to explicitly ask the question, in an essay entitled "Character". He framed it in the context of a fixed human moral character: since neither experience nor philosophy nor religion can improve a person, he asked, what is the point of life at all?
Large-data studies of flow experiences have consistently shown that humans experience meaning and fulfillment when mastering challenging tasks, and that what matters is the approach to a task, not which task is chosen. Flow can be obtained by prisoners in concentration camps and occurs only slightly more often in billionaires, suggesting meaning is not tied to material circumstances.
Greater meaning in life has been associated with reduced risk of Alzheimer's disease, reduced risk of heart attack among those with coronary heart disease, reduced risk of stroke, and increased longevity in both American and Japanese samples. In 2014 the British National Health Service began recommending a five-step plan for mental well-being based on meaningful lives.
Plato held that the meaning of life is attaining the highest form of knowledge, the Idea of the Good, from which all just things derive value. Aristotle argued that the highest good is eudaemonia, usually translated as happiness or flourishing, achieved not through theoretical study alone but through the actual practice of virtuous activities.
Albert Camus defined the Absurd as the fundamental disharmony between the individual's search for meaning and a universe that is indifferent to that search. Camus endorsed acceptance of the Absurd as the most honest response, most notably in his 1947 allegorical novel The Plague, arguing that people can live with dignity and "secular saintliness" despite the absence of external meaning.