with
expression upon a differing system. There is 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 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. One's 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.

You see, I hope, what I mean when I say that the universe of
molecular physics is at a different level from the universe of common
experience;--what we call stable and solid is in that world a freely
moving system of interlacing centres of force, what we call colour and
sound is there no more than this length of vibration of that. We have
reached to a conception of that universe of molecular physics by a great
enterprise of organised analysis, and our universe of daily experiences
stands in relation to that elemental world as if it were a synthesis of
those elemental things.

I would suggest to you that this is