operations, and into the scheme of my philosophy.... These then are my first two charges against our Instrument of Knowledge, firstly, that it can work only by disregarding individuality and treating uniques as identically similar objects in this respect or that, so as to group them under one term, and that once it has done so it tends automatically to intensify the significance of that term, and secondly, that it can only deal freely with negative terms by treating them as though they were positive. But I have a further objection to the Instrument of Human Thought, that is not correlated to these former objections and that is also rather more difficult to convey. Essentially this idea is to present a sort of stratification in human ideas. I have it very much in mind that various terms in our reasoning lie, as it were, at different levels and in different planes, and that we accomplish a large amount of error and confusion by reasoning terms together that do not lie or nearly lie in the same plane. Let me endeavour to make myself a little less obscure by a most flagrant instance from physical things. Suppose some one began to talk seriously of a man seeing an atom through a microscope, or better perhaps of cutting one in half with a knife. There are a number of non-analytical people who would be quite prepared to believe that an atom could be visible to the eye or cut in this manner. But any one at all conversant with physical conceptions would almost as soon think of killing the square root of 2 with a rook rifle as of cutting an atom in half with a knife. Our conception of an atom is reached through a process of hypothesis and analysis, and in the world of atoms there are no knives and no men to cut. If you have thought with a strong consistent mental movement, then when you have thought of your atom under the knife blade, your knife blade has itself become a cloud of swinging grouped atoms, and your microscope lens a little universe of oscillatory and vibratory molecules. If you think of the universe, thinking at the level of atoms, there is neither knife to cut, scale to weigh nor eye to see. The universe at that plane to which the mind of the molecular physicist descends has none of the shapes or forms of our common life whatever. This hand with which I write is in the universe of molecular physics a cloud of warring atoms and molecules, combining and recombining, colliding, rotating, flying hither and thither in the universal atmosphere of ether.