IV. Thought as the Instrument of Knowledge

There are people who say it is impossible to ascertain with certainty whether thought is right or wrong, and that, so far, our starting-point is a doubtful one. It would be just as intelligent to raise doubts as to whether a tree is in itself right or wrong. Thought is a fact, and it is meaningless to speak of the truth or falsity of a fact. I can, at most, be in doubt as to whether thought is rightly employed, just as I can doubt whether a certain tree supplies wood adapted to the making of this or that useful object. It is just the purpose of this book to show how far the application of thought to the world is right or wrong. I can understand anyone doubting whether, by means of thought, we can gain any knowledge of the world, but it is unintelligible to me how anyone can doubt that thought in itself is right.