That is why “all” and “nothing” are dichotomous, without a range. This is perfectly clear in considering psychological tests of maximal performance. You cannot interpret the results at all unless you assume eithermaximal motivation or no motivation at all. Only in these two conditions can you validly compare responses, and you must assume the former, because if the latter were true, the subject would not do anything. Given variable¬†motivation, he will do something, but you cannot understand what it is.