Yoga means Union. We may now consider what Yoga really is. Let us go for a moment into the nature of consciousness with the tail of an eye on such sciences as mathematics, biology, and chemistry. In mathematics the expression 'a' plus 'b' plus 'c' is a triviality. Write 'a' plus 'b' plus 'c' equals 0, and you obtain an equation from which the most glorious truths may be developed.
Similar facts occur in chemistry.
All these combinations, these unions, are Yoga. Yoga means Union. Only by making a distinction between it and the rest of the world. Now, there is nothing strange or wonderful about all this. The study of the principles of Yoga is very useful to the average man, if only to make him think about the nature of the world as he supposes that he knows it.