The nature of the conflict in Hemingway's "A Clean, Well-Lighted Place" is essentially existential. With minimal authorial intervention, it is left to the reader to determine what struggles exist in the old man and the older waiter. The tension of the conflict resides in the dialogue of the two waiters, "two different kinds." The younger waiter lets the old man's brandy glass pour over until it "slopped over and ran down the stem." He is not ordered, and accuses the old waiter of "talking nonsense." Like the old man who attempted suicide, since his life had nothing left, the old waiter also seeks a clean, well-lighted place, a place of order and light against the "nada," the nothingness of life.
In an essay [cited below] entitled, "Character, Irony, and Resolution in 'A Clean, Well-Lighted Place,'" Warren Bennett observes the dichotomy between confidence as exhibited by the younger waiter and despair found in the older waiter; he notes, also, the irony that works throughout the story. Bennett perceives the conflict between this younger confidence and the older despair.
This profound difference between the two waiters is "embedded" in the casual conversation about the old man who has attempted suicide because he has lacked anything to live for. This despair the old waiter understands as he, too, seeks a lighted place against the darkness of "nada," and his despair and the anguish of being alone. His is the existential struggle to find some meaning in the nothingness and absurdity of life.
As one grows old and death draws near one becomes more and more painfully aware of the meaninglessness, the nothingness-nada-of life. Religion which is meant to be a source of strength and comfort proves ineffective in the present situation. This is the tragic situation of the old waiter and the old drunken customer in Hemingway's "A Clean, Well-Lighted Place."
Hemingway reveals the thoughts of the older waiter through an interior monologue:"What did he fear? It was not a fear or a dread, it was a nothinghe knew too well. It was all nothing and a man was a nothing too." A feeling of numbness which is worse than the fear of death overwhelms the older waiter and in a desperate attempt to overcome this feeling of numbness he tries to repeat the Lord's Prayer and Hail Mary but ends up repeatedly using the word 'nada' and 'nothing,' thus foregrounding the ineffectiveness of these two prayers.
It is this overwhelming feeling of 'nothingness' which makes the older waiter sympathise with the old drunken customer. The well lighted cafe offers a temporary refuge from this cruel nothingness which has already driven the old man to attempt suicide.
Hemingway witnessed two world wars and lived in a time when people had lost faith in organised religion as a solution to their problems. One of the popular schools of philosophy during this time was 'Existentialism,' - which encouraged a cynical and pessimistic way of understanding the reason and purpose for one's existence on this earth. The existentialists believed that life had little or no meaning at all. This notion is best expressed in the thoughts of the waiter: "It was all nothing and a man was a nothing too."
Heminway, by portraying very poignantly the existentialist angst of the two old men in his short story reveals the tragedy and loneliness of old age in general.