context: A man looks back while laughing and walking.
hypothesis: It is probable that a man walks and hears a funny joke and starts to laugh.
valid_hypothesis: It is probable that a man walks and hears a funny joke and starts to laugh.
invalid_hypothesis: It is improbable that a man walks and hears a funny joke and starts to laugh.
hypothesis_assertion: A man walks and hears a funny joke and starts to laugh.