With this book Chomsky,
Chomsky, like all good politicians, has changed his mind on how the mind works.
His original theory was that brains are equipped with a "universal grammar"
that predisposes us to learn languages,
and that the sentences of a language can be accounted for by a set of rules (its grammar).
Now he believes that there is no universal grammar,
just a circuit in the brain that is more or less plastic:
change the connections and you get one or the other language.
There are no rules of grammar,
but there are associations between sounds and concepts:
we learn a concept when we make the connection with a sound.
Basically, we "rediscover" concepts that we have always unconsciously known, since prehistoric times
Chomsky is probably correct in stating that the "rules" of grammar are only a consequence,
==.
Most linguists simply neglect history and the fact that we are a species capable of learning and of transmitting knowledge.
Were we a species that does not change over the centuries,
A study of the history of language would probably show that there are many more regularities than one supposes irregular verbs probably have a reason to be what they are (they may have been regular in the past, according to a long-forgotten rule), words may be derived from very simple sounds, idiomatic expressions may be based on bodily features, etc. If one studies history, there might be simple explanations for everything. If one takes the human world as it is today and tries to make sense of it, the task is virtually impossible.