A person who is interested in studying languages is faced with a very definite empirical problem. He's faced with an organism, a mature, let's say adult, speaker, who has somehow acquired an amazing range of abilities, which enable him in particular to say what he means, to understand what people say to him, to do this in a fashion that I think is proper to call highly creative ... that is, much of what a person says in his normal intercourse with others is novel, much of what you hear is new, it doesn't bear any close resemblance to anything in your experience; it's not random novel behaviour, clearly, it's behaviour which is in some sense which is very hard to characterise, appropriate to situations. And in fact it has many of the characteristics of what I think might very well be called creativity.
Now, the person who has acquired this intricate and highly articulated and organised collection of abilities-the collection of abilities that we call knowing a language-has been exposed to a certain experience; he has been presented in the course of his lifetime with a certain amount of data, of direct experience with a language.
We can investigate the data that's available to this person; having done so, in principle, we're faced with a reasonably clear and well-delineated scientific problem, namely that of accounting for the gap between the really quite small quantity of data, small and rather degenerate in quality, that's presented to the child, and the very highly articulated, highly systematic, profoundly organised resulting knowledge that he somehow derives from these data.
Furthermore we notice that varying individuals with very varied experience in a particular language nevertheless arrive at systems which are very much congruent to one another. The systems that two speakers of English arrive at on the basis of their very different experiences are congruent in the sense that, over an overwhelming range, what one of them says, the other can understand.
Furthermore, even more remarkable, we notice that in a wide range of languages, in fact all that have been studied seriously, there are remarkable limitations on the kind of systems that emerge from the very different kinds of experiences to which people are exposed.
There is only one possible explanation, which I have to give in a rather schematic fashion, for this remarkable phenomenon, namely the assumption that the individual himself contributes a good deal, an overwhelming part in fact, of the general schematic structure and perhaps even of the specific content of the knowledge that he ultimately derives from this very scattered and limited experience.
A person who knows a language has acquired that knowledge because he approached the learning experience with a very explicit and detailed schematism that tells him what kind of language it is that he is being exposed to. That is, to put it rather loosely: the child must begin with the knowledge, certainly not with the knowledge that he's hearing English or Dutch or French or something else, but he does start with the knowledge that he's hearing a human language of a very narrow and explicit type, that permits a very small range of variation. And it is because he begins with that highly organised and very restrictive schematism, that he is able to make the huge leap from scattered and degenerate data to highly organised knowledge. And furthermore I should add that we can go a certain distance, I think a rather long distance, towards presenting the properties of this system of knowledge, that I would call innate language or instinctive knowledge, that the child brings to language learning; and also we can go a long way towards describing the system that is mentally represented when he has acquired this knowledge.
I would claim then that this instinctive knowledge, if you like, this schematism that makes it possible to derive complex and intricate knowledge on the basis of very partial data, is one fundamental constituent of human nature. In this case I think a fundamental constituent because of the role that language plays, not merely in communication, but also in expression of thought and interaction between persons; and I assume that in other domains of human intelligence, in other domains of human cognition and behaviour, something of the same sort must be true.
Well, this collection, this mass of schematisms, innate organising principles, which guides our social and intellectual and individual behaviour, that's what I mean to refer to by the concept of human nature.