ABSTRACT
Let us suppose that we have conceived a theoretical scheme where there enters a certain relation expressing a variable y as a function of the variables x xn1, ..., , let us say y f x xn= ( ,..., )1 . We may ask whether it is possible to determine the concrete form of the function from empirical observations giving us specific values for the variables. Obviously, from a strictly mathematical point of view, if the function is considered as an absolutely arbitrary function, any finite number of observations will be insufficient to determine the function. But it is a concern of little importance from a practical point of view as the overwhelming share of the functions that may come under consideration have to satisfy certain conditions of continuity or of limited variation or other conditions allowing them to be determined with sufficient precision if we know their values in certain discrete points.
