In the short story "The Third Level" by Jack Finney, does the third level in the Grand Central Station really exist or, is it just in Charley's imagination? Does Sam Wiener really go to 1894, or is the letter some sort of imagination of Charley?
A literary text is not meant to be read in the same way as, say, a newspaper article. When we discover an internal contradiction in a newspaper article or something that seems to be in conflict with reality as a know it, we want to find out which of the two contradictory statements is right. After we have established that, we move on; the article does not require further analysis. If we find an internal contradiction in a literary text, however, we shouldn't satisfy ourselves with only finding out which statement is true and which is not. We should also look at how the text tries to convince us of the truthfulness of either statement or point of view. Looking at these mechanisms is a more genuinely literary way of reading than trying to establish the truth.
Jack Finney's short story contains both elements that try to convince us of the realibility of the narrator—and thereby of the reality of the third level—and elements that allow us to question his reliability.
First, the narrator tries to convince us that he is a very reasonable person by telling us he consulted a psychiatrist. His apparent willingness to accept a psychological explanation for seeing the third level is meant to convince us that he is not a lunatic who lives in a parallel universe. The second method of convincing us of the reality of the third level is the enumeration of many facts that can be verified. Grand Central is a real rail terminal in New York, although its official name has been Grand Central Terminal since 1910—1913. The Twentieth Century, or rather the 20th Century Limited, was a real express passenger train that ran between Grand Central in New York and LaSalle Street Station in Chicago from 1902 to 1967. The tunnel between Grand Central and The Roosevelt Hotel really existed (Wikipedia: "The Roosevelt Hotel was at one time linked with Grand Central Terminal via an underground passage that connected the hotel to the train terminal. The passageway now terminates just across the street from the hotel's East 45th Street entrance.") The newspaper The World is a bit harder to identify; it may be the New York World, published in New York City from 1860 until 1931, or its evening edition The Evening World, published from 1887 to 1931. However, the narrator manages to identify the edition he saw to 11 June 1894, during the second presidency of Grover Cleveland (1893–1897). The fact that he does not get away with using present-day currency is another element of realism that a dream would not necessarily "enforce".
On the other hand, the story also contains many hints that the third level may be what the psychiatrist calls "a waking-dream wish fulfillment". For example, after talking to the psychiatrist, he tells us, "Everybody wants to escape, but they don't wander down into any third level at Grand Central Station," signalling an unwillingness to admit the third level may be an illusion. His psychiatrist and other friends stamp collecting as a "temporary refuge from reality". But there are other, subtler elements that suggest the third level is an illusion. The narrator mentions that he got lost in Grand Central on several occasions; he once ended up in The Roosevelt Hotel, even though walking along a mile-long tunnel should provide enough time to realise that you're not walking in the right direction. He admits that Grand Central may be a way of escape for some people. On the "third level" he sees a "Currier & Ives locomotive" even though Currier and Ives was a printmaking firm, not a locomotive manufacturer. In other words, he is mistaking a print for reality. Finally, the narrator's description of life in Galesburg, Illinois, in 1894 is highly idealised; there is no room for anything negative.
The story could have ended at "But I’ve never again found the corridor that leads to the third level at Grand Central Station, although I’ve tried often enough" or at "I went back to my stamps". In that case, it would have been easy to dismiss it as just another "it was just a dream" story. Many readers dislike this narrative motif because it implies that nothing happened in "reality". See for example:
- How do you feel about the "It Was All Just a Dream" trope? on reddit/writing,
- All Just a Dream on TV Tropes:
Normally, this really grates on the audience, as in general it tends to completely undermine the story that's just been told; if none of it was real, then what was the point?
- #6: It Was All Just A Dream ("A Hundred Cliches That Really Need To Die"):
Turns out all the events in the plot were a dream created by the main character, and none of that really happened. You then throw the remote at the TV in frustration, having wasted two hours of your life for this.
Having the events of a story just be a product of a dream is the cheapest cop out any author can use to avoid making a sequel. Not only that, but it is one of the most frustrating cliches out there.
(That does not mean the motif must be avoided at all cost. See Why using the "It Was All Just a Dream" Trope? and Is it okay to use "It was all just a virtual world / dream" for a plot twist?, both on Writing Stack Exchange.)
After the narrator tells us that he went back to his stamps, the story has an unexpected twist that turns the "it was just a dream" motif on its had and tries to convince it that the story about the third level was real. First, it tells us that both the narrator and his wife are now looking for the third level because that is where Sam Weiner appears to have gone. The narrator found out about this through a first-day cover. In other words, the very hobby that was originally used as evidence of his escapism now provides evidence that the third level is real. In addition, Sam Weiner is the name of the narrator's psychiatrist, so the person who is most competent to diagnose the narrator's escapism provides evidence that going back to 1894 is possible. This vindicates the narrator completely. The only thing that stands between the reader and admitting that the third level is real is the knowledge that he is reading fiction and that time travel only exists in fiction.
 See also The Progress of the Century – The Lightning Steam Press. The Electric Telegraph. The Locomotive. The Steamboat. on the website of the Metropolitan Museum of Art, and 19th Century Locomotive History on ThoughtCo. The latter article reproduces a Currier and Ives lithograph and points out, "Commercial lithographers were highly motivated to produce prints they could sell to the public. Currier & Ives, with their developed sense of popular taste, must have believed this romantic view of the railroad playing a major part in the settlement of the west would strike a chord."
The Third Level was merely a hallucination. The narrator, Charley uses the Third Level as an escape medium from the harsh reality of the war years that prevailed at the time. Charley was unhappy with the reality as the world was full of insecurity, fear, war, and worry. It was the intense longing to return to his 1890's lifestyle in Illinois that led to this wishful thinking.
So all these interpretations direct to the conclusion that the letter from Sam Weiner is merely a product of Charley's imagination as both Sam and the narrator existed in the present timeline. This also clearly justifies the statement that philately was a means of 'temporary refuge' from reality to Charley.