Alfred Binet, answered from the texts and cited to the page.
I built the scale for a single, practical purpose: to identify, among schoolchildren, those who could not follow ordinary instruction and needed special help.12 It is a graded series of tasks, ordered by difficulty and calibrated against what normal children of each age can do, so that we may say where a given child stands. That is all it is, and it is a great deal.
What it is not is a measuring-rod of some fixed, innate quantity of intelligence stamped in a child at birth. The scale measures a present state, a performance here and now, which is the product of the child's nature and of everything that has acted upon it — its schooling, its home, its health, its habits of attention. To read a low result as the verdict of a permanent and unalterable incapacity is to abuse the instrument and to wrong the child.
I devised a diagnosis in order to prescribe a remedy, not a sentence. The number tells us which children need our help; it does not tell us that our help is useless.3
The practical question which presents itself does not lack elegance in its simplicity; here it is: being given any school, whose population numbers from 100 to 800 pupils, visit the classes and discover the subnormals scattered among them. Must we examine one by one all the pupils in a school? No, certainly not! That would be altogether useless.The Development of Intelligence in Children, p. 169
This is very useful in practice. We have stated that the scale of reading was founded on experiments made by M. Vaney at the end of the school year. We have modified it slightly in consequence of experiments made by ourselves in February. It may be of interest to give here the table arranged by M. Vaney. It has been arranged not by age, but by class.Mentally Defective Children
We do not know, and cannot divine. How much is he behind normal children of the same age? We know this no better. This brings us very naturally to an exposition of the plan of our work. It will be seen that our directing idea is different from that of M. Blin although our system of measurement, like his, is essentially psychological. A. BiNET AND Th. Simon.The Development of Intelligence in Children, pp. 37–38
Binet's own conception — the scale as a practical, individual, diagnostic instrument measuring present performance, not fixed innate capacity — is well documented and is now the basis of his rehabilitation against the tradition that claimed him. That tradition, built by Goddard and Terman, reconceived the test as a measure of a fixed, largely hereditary, unitary intelligence quotient and put it to hereditarian, tracking, immigration- restriction, and eugenic uses that ran directly against Binet's stated views; Gould's Mismeasure of Man made the contrast canonical. The modern science of intelligence finds measured cognitive ability to be substantially heritable within groups yet also environmentally responsive and educable, and holds that a test score is a performance measure, not a fixed essence — a picture much closer to Binet's cautious diagnostic conception than to the reified IQ of his heirs.