The fact of illusion and error is in various ways forced early upon the mind; and the ideas by which we try to understand the universe, may be considered as attempts to set right our failure. In this division of my work I shall criticize some of these, and shall endeavour to show that they have not reached their object. I shall point out that the world, as so understood, contradicts itself; and is therefore appearance, and not reality.
In this chapter I will begin with the proposal to make things intelligible by the distinction between primary and secondary qualities. This view is old, but, I need hardly say, is far from obsolete, nor can it ever disappear. From time to time, without doubt, so long as there are human beings, it will reappear as the most advanced and as the one scientific theory of first principles. And I begin with it, because it is so simple, and in the main so easily disposed of. The primary qualities are those aspects of what we perceive or feel, which, in a word, are spatial; and the residue is secondary. The solution of the world’s enigma lies in taking the former as reality, and everything else somehow as derivative, and as more or less justifiable appearance.
The foundation of this view will be known to the reader, but for the sake of clearness I must trace it in outline. We assume that a thing must be self-