The Irony of Memory
Memory is a way for a person to retain thoughts, feelings, and experiences from one moment in life to the next. Its purpose is to allow someone to recall things from his past, but the irony is that all memories are colored and shaped through the lens of one's own perspective. Memory doesn't allow you to remember what really happened, but only your impressions of it, as seen through the narrative of "Peaches."
The Irony of the Pram
The pram (short for "perambulator," a device used to wheel babies around) has an inherent irony in the narrator's vivid memory in "Peaches." In the seat of the pram is usually a baby, which is an occupant of very high value in the eyes of the one pushing the pram. The seat holds things of great meaning and significance, so it is ironic that it is being used to transport peaches in the story.
This irony, however, might inform the reading that the peaches symbolize more than themselves (the mother's fidelity), and therefore they do actually carry great value.
The Irony of Peaches in Winter
The irony of the narrator's vivid memory in "Peaches" alerts him to a possible contradiction, throwing the whole scene in doubt: he remembers it being a cold winter night, but why would they be taking peaches to the next village in winter, which isn't peach season? The irony of fresh fruit in a season of frozen stasis drives much of the plot of the story.
The Irony of Speed
In the memory in "Peaches," the narrator and his mother must hurry to get home; there is a feeling of anxiety and urgency about the scene. The pram, though, severely limits their speed; if they go any faster, the bumps in the road will damage the skin of the peaches. This cruel irony, their progress inhibited by the very items that make the trip worth it, bears many similarities to the ironies of memory found in the story.
The Irony of the Soldier's Wife
In "Peaches," the narrator remembers being a young boy and thinking that his mother, being the loyal and dutiful wife of a soldier, would never delight in vulgar talk with another man while her husband was away. In retrospect, however, the narrator realizes that she was, in fact, doing so, behaving in a manner discontinuous with the expectations of a soldier's wife.
The Absurdity of Progress
Stories with a strong scientific or technology theme frequently have an ironic subplot where advancement brings about unanticipated bad effects. This irony emphasizes how technological improvements intended to make life better for humans can occasionally result in increased dehumanization or alienation.