case) allowing one to express the required answer in a more accurate way. By using modern powerful numeral systems where additional numerals for expressing the numbers ‘three’ and ‘four’ have been introduced, we can notice that within ‘many’ there are several objects and the numbers 3 and 4 are among these unknown to Pirahã) objects.

Thus, the choice of the mathematical language depends on the practical problem that is to be solved and on the accuracy required for such a solution. In dependence of this accuracy, a numeral system that would be able to express the numbers composing the answer should be chosen.

Such a situation is typical for natural sciences where it is well known that instruments bound and influence results of observations. When physicists see a black dot in their microscope they cannot say: The object of the observation *is* the black dot. They are obliged to say: the lens used in the microscope allows us to see the black dot and it is not possible to say anything more about the nature of the object of the observation until we change the instrument - the lens or the microscope itself - by a more precise one. Then, 