Yoga is a science, and not a vague dreamy drifting or imagining. It is an applied science, a systematized collection of laws applied to bring about a definite end. It takes up the laws of psychology, applicable to the unfolding of the whole consciousness of man on every plane, in every world, and applies those rationally in a particular case. This rational application of the laws of unfolding consciousness acts exactly on the same principles that you see applied around you every day in other departments of science.