re. innateness hypothesis

It seems to me that the overall picture of the minimalist program is really a "philosophical theory" of what human language is and how it works; it has some theoretical merits and some linguistic evidence, but it is to be explored and verified by further scientific findings.

This "philosophical" flavor of this 'program' reminds me of the "innateness hypothesis." The innateness hypothesis has renewed the debate between empiricism and rationalism, and if it is correct, rationalism is to be favored. I'm wondering how far this preference can go and how deep it is.

The question is how we should understand what "innate" mean here, or exactly "what" is innate in the proposed hypothesis. One possibility is to interpret the innateness as 'written in our gene' and it's a form of biological growth. If so, I'm a little doubtful if this may be called 'innate knowledge.'

Regarding the notion of biological growth, we know that infants cannot eat solid food and they can't even drink certain liquid food until certain months. This is so because their digest system and stomach are not ready yet; the biological growth is not ripe. If what's special about human language is just like our stomach's ability to digest food, then what is innate is at most a kind of 'ability,' rather than 'knowledge;' do we want to say that human have 'innate knowledge' of how to digest?

Perhaps we can apply the distinction between 'knowing how' and 'knowing what' and clarify that the innateness hypothesis does claim that human language is innate, but it's an innate 'knowing how.' The task of the linguists, then, is to spell out the 'knowing-how' in terms of 'knowing-what.' But it may be a question whether all 'knowing-how' and be translated into some 'knowing-what.'

Another way to think of the innateness hypothesis is really to think of it as knowledge and 'knowledge of what', and this knowledge is written in the gene. Then I wonder how it can correctly be labeled as knowledge, for knowledge must have justification. Depending on one's choice of what counts as justification, whether our knowledge of universal grammar is 'innate knowledge' can have very different answers. I think if we adopt the internalist notion of justification, 'innate knowledge' of language can't really be knowledge, simply because we really don't know, and are not aware of what justifies it, even though he mechanism that produces it is innate. However, if we take the reliablist approach, as long as the relevant production mechanism is reliable, its product counts as knowledge, then innate knowledge of language makes sense. And indeed, what's written in our gene should be pretty reliable, since it's the result of evolution. In this sense, whether linguistic knowledge is innate knowledge turns on which theory of justification we endorse.

Going back to how much weight the innateness hypothesis can put on the empiricism/rationalism debate, we've seen that there are many factors to be considered. We need a clear definition of innateness, a notion of knowledge and justification. To say that the success of 'innateness hypothesis' definitely favors rationalism just oversimplifies the issue.