Frank the Wrabbit is a pre-scientific thinker much in the mold
of Plato. Plato, like Frank, was a hot-shot top-grade intellectual
giant, at least within his particular milieu. Frank has his corner
of the woods, and Plato had ancient Greece.
In Plato's day, there wasn't a lot of scientific thinking going around; at least, it wasn't formalized the way it is now. Grand and beautiful theories were formed, and if you wanted to try one out, you argued it out with other theoreticians. This process was called "Dialectic".
Plato argued his ideas out with characters of his own invention (often referred to as the "Platonic Stooges"), who were almost as dumb as the other rabbits in Frank's world. Not surprisingly, Plato whipped the stooges hands down.
There was no real skeptical appraisal, and no experiments.
Frank, too, has a lot of beautiful theories that he invents, and believes. He never compares his ideas to the Real Universe, and why should he, since he's the smartest creature he knows about.
Although Frank never does an experiment, an Experiment does him! That is to say, the Real Universe forces itself on him in the form of a farmer who collects his carrots. Frank has to revise his theories, and, possibly, an inkling of scientific thought is born.
At first glance, the mother seems like a healthily skeptical
person. She believes very little, and this is good. Most people
believe far too much. Unfortunately, she suffers from the opposite
problem from Frank; she can criticise theories, but she can't
invent new ones. When the Universe contradicts her theory (This
Rabbit is Dead), she loses her marbles. Nothing can be trusted.
It's a pity that the mother and the Wrabbit cannot comunicate; together, they would make a powerful combination. Alas, this has been prevented by an omnipotent and malicious film-maker.
The Little Girl is the worst of the lot. She neither formulates nor criticises ideas. There is no preference here for elegant, simple, well-tested theories. Her mind is like any foetid swamp; anything that lands in it will grow. (Those interested in a theory of why theories survive might find Richard Dawkins interesting. Scientific Verification is one of the least important predictors of a theory's popularity.)
An Aside: On Other People in the Film
But Frank's the main character. All that can reasonably be
asked of this film is that we see how Frank thinks, and reflect
on what might be wrong with Frankian speculation.
Frank creates theories that would have huge implications, if true. He bases those theories on rather slight evidence. He feels confident about the theories, since nothing in his daily life seems to contradict them.
The only thing he lacks is a critical, skeptical side. He does not actively search for contrary evidence. He therefore endangers himself, through blissful, uncritical acceptance of untested theory.
An Aside: On Education and Politics