How can we automatically model human natural language understanding?

Imagine that we have heard the sentence “The dog chases the cat” several times, but we haven’t ever heard the sentence “The cat chases the mouse”. As soon as we hear it, we infer that cats do some things similarly to dogs: at least they also chase. But we know even more: we also know that “cat” have the same syntactic behaviour in the latter sentence as “dog” in the former sentence, and we also know that “cat”, in the first sentence, has the same role as “mouse” in the second sentence, but… what is a “mouse”? Oh! We don’t know yet, but as the pattern detection and the learning process goes on, we will know soon. People are smart, people can generate new knowledge by just listening or reading: we all make a lot of assumptions that are usually correct.