On "The Water That Falls on You from Nowhere"

In John Chu's "The Water That Falls on You from Nowhere, water falls from the sky whenever a person "lies". This mechanic, in fact the only aspect of science fiction in the entire short story, is interesting because it is never made clear what it means to lie. Terrence suggested in class that the world references a sort of "universal truth" before deciding whether or not to drop water on its unfortunate victim. On first glance, this seems entirely possible, but I believe that intention plays a larger role in the water than the objective truthfulness of the statement.

For example, when Matt and his sister are discussing Gus while chopping vegetables, Matt remarks that he doesn't understand what his sister means, while thinking, "there's a good chance that she'll miss the sarcasm...the water gets it though and I stay dry". In this passage, Matt admits that he is using sarcasm, implying that he does understand what his sister is saying, making his actual statement an objective lie. However, the water is able to pick up on his sarcasm, detecting his intentions before deciding not to fall on him.

This idea changes what we discussed near the end of class on whether or not Matt and Gus will be able to maintain a healthy relationship. I brought up that water falling on Matt's sister when she claims that Gus will eventually "cheat on you or dump you", meant that her statement was a universal falsehood under Terrence's definition. Under a framework where the water reads intentions and not objective truths, water falling merely indicates that Matt's sister did not truly believe what she was saying, which is entirely possible given the context of the story. Regardless, the water drenching Matt's sister only tell us about her and nothing about Gus in this case.

Thoughts?