The growth of the nervous system from beginning to end is dominated by 'a totally integrated matrix, and not a progressive integration of primarily individuated units'. The organism is not a sum of its reflexes, but on the contrary 'the mechanism of the total pattern is an essential component of the performance of the part, i.e. the reflex'. The stimulus-response scheme cannot explain even embryonic behaviour, because movements appear long before the motor neurons of the reflex arc are connected with the sensory neurons. This centrifugal mode of development means that the individual acts on its environment before it reacts to its environment.