Very interesting post, @alison! Your question got me into a number of rabbit holes. Forgive me if my reflections detract in any way!
I first wondered what the difference between allegory and parable was, as my initial thought was that neither of them are necessarily what we would call non-fictionā¦and typically evangelicals can get uptight about calling stories in the Bible āfictionā. (Sidebar: āfictionā has a later historical etymology)
As I understand it, both allegory and parable are stories told with illustrative purpose. In fact, according to Britannica, a parable is a type of allegory. Here is their definition of allegory:
allegory, a symbolic fictional narrative that conveys a meaning not explicitly set forth in the narrative. Allegory, which encompasses such forms as fable, parable, and apologue, may have meaning on two or more levels that the reader can understand only through an interpretive process.
Perhaps itās more helpful to then bring in the more modern concept of biography, which seems to more tied to the even more modern notion of āhistorical accuracyā? When Jesus spoke in parable, he wasnāt necessarily giving a biography of, say, a particular, historical traveller who was mugged on the road to Jericho and passed by by particular, historical religious leaders but not by a particular, historical Samaritan. He, of course, was telling what was most likely a fictional story in order to illustrate a deep truth. (Sidebar #2: myth also has this function, and the creation and flood accounts are often viewed as myth! That is, stories told around an historical event ā creation, flood ā that convey truth on a level not limited to the historical.)
Soā¦ Could Jonah be only allegory? I think itās unlikely. I agree with you that Jesusā reference to the āmen of Ninevahā who will judge that generation would lose a bit of its gravitas if the āmen of Ninevahā were not real people. Or, at least it does to me in my world that values āhistorical accuracyā(ā¦which, sidebar #3, is a later notion emerging from the rationalism of the Enlightenment). But I also donāt think the story of Jonah loses its truth by being only allegory.
Could Jonah be what we would consider to be biography (that is the story of an historical figure)? Yes. I donāt know if we can āhistorically confirmā every single part of the story, but he is mentioned as a real person in 2 Kings 14:25 ESV, which is a history book.
Do I believe he could have survived being swallowed by a fish and spat back out? Yes, because like @alison, I believe in a God who can accomplish extraordinary things. Did it literally happen? Iām agnostic on it. I do believe that, at the very least, Jonah experienced a prophetic call, refused to obey it, went somewhere very dark (no doubt psychologically) for a period of time before he re-emerged and went to preach to Ninevah, where the people repented. All the other amazing things that are recorded in that book donāt necessarily have to be literally/historically/actually true because my faith does not rest on them.
I say all this because I do not see this as either-or. Allegory and biography are not opposed to one another. Stories of historical people can (and very often do!) take on metaphorical meanings! People become symbols; lives take on symbolic meaning.
Which leads me to the why thread of this prophet story, for the what and why are interconnected. Recorded stories of historical figures generally have a why. That is, even āhistorical accuracyā has an agenda. People seek to tell āhistorically accurateā stories (and, subsequently, demand āliteral-nessā of others) for a reason. The story of Jonah would have been recorded and studied by rabbis for a reason. I rather doubt it was so that people could merely know what happenedā¦as if reading a news story. Itās a larger story about God and one prophetās engagement with him re. a salvation of an enemy.
To me, itās a little bit historical biography and a little bit allegory or myth. It communicates something about God, and it communicates something about us humans that makes it all relatable.