You will tell me this is not mere judgment but formal reasoning. Just so; but do not you see that as soon as the mind has got any ideas at all, every judgment is a process of reasoning? So that as soon as we compare one sensation with another, we are beginning to reason. The art of judging and the art of reasoning are one and the same. Emile will never learn dioptrics unless he learns with this stick. He will not have dissected insects nor counted the spots on the sun; he will not know what you mean by a microscope or a telescope. Your learned pupils will laugh at his ignorance and rightly, I intend him to invent these instruments before he uses them, and you will expect that to take some time. This is the spirit of my whole method at this stage. If the child rolls a little ball between two crossed fingers and thinks he feels two balls, I shall not let him look until he is convinced there is only one. This explanation will suffice, I hope, to show plainly the progress made by my pupil hitherto and the route followed by him. But perhaps the number of things I have brought to his notice alarms you. I shall crush his mind beneath this weight of knowledge. Not so, I am rather teaching him to be ignorant of things than to know them. I am showing him the path of science, easy indeed, but long, far-reaching and slow to follow. I am taking him a few steps along this path, but I do not allow him to go far. Compelled to learn for himself, he uses his own reason not that of others, for there must be no submission to authority if you would have no submission to convention. Most of our errors are due to others more than ourselves. This continual exercise should develop a vigour of mind like that acquired by the body through labour and weariness. Another advantage is that his progress is in proportion to his strength, neither mind nor body carries more than it can bear. When the understanding lays hold of things before they are stored in the memory, what is drawn from that store is his own; while we are in danger of never finding anything of our own in a memory over-burdened with undigested knowledge.