A person might say on one day:
It is hot outside - let's go out for a picnic! It is healthy.
Another person might say on the same day in the same place:
It is hot outside - stay inside where it is safe from extreme weather! It is unhealthy.
The weather and health together is our internal model of what is happening at a physical and biochemical level. It is not actually what happens - simply an analogy we can use to communicate an idea.
Let me give another example:
One teacher might say
This group of students are so quiet. It's unhealthy. We need to break up the group.
Another teacher might say for the same students on the same day:
This group of students are so quiet. It's so healthy. We need to encourage more students to be like this.
In this example health is a metaphor for something that is assumed - but not defined. It is used both ways. The analogy of 'healthy group behaviour' is ambiguous in this conversational context.
One possible answer to this might be metaphysical conceit - but that seems like a poetic term, and possibly limited to spiritual poetry.
My question is: What is a word for when an analogy could be used for both sides of an argument?