This radical denial is for the less bold. Doubtless the organic cause of right-handedness is dubious and insufficient, and difficult to distinguish from influences which act on the individual from outside and shape him; but this is no reason for dogmatically denying the action of the physical factor. Moreover, in some cases where external influence and organic tendency are in conflict, it is possible to affirm that the unequal skill of the hands is connected with an anatomical cause. In spite of the forcible and sometimes cruel pressure which society exerts from their childhood on people who are left-handed, they retain all their lives an instinctive preference for the use of the left hand. 7 If we are forced to recognise here the presence of a congenital disposition to asymmetry we must admit that, inversely, for a certain number of people, the preponderant use of the right hand results from the structure of their bodies. The most probable view may be expressed, though not very rigorously, in mathematical form: in a hundred persons there are about two who are naturally left-handed, resistant to any contrary influence; a considerably larger proportion are right-handed by heredity; while between these two extremes oscillate the mass of people, who if left to themselves would be able to use either hand equally, with (in general) a slight preference in favour of the right. 8 There is thus no need to deny the existence of organic tendencies towards asymmetry; but apart from some exceptional cases the vague disposition to right-handedness, which seems to be spread throughout the human species, would not be enough to bring about the absolute preponderance of the right hand if this were not reinforced and fixed by influences extraneous to the organism.