Meditation is a special kind of concentration. In ordinary concentration, the mind is focused on one particular subject, and there can be many divergent thoughts related to that particular subject. Here the subject is one, but thoughts are many and dissimilar. By the world ‘meditation’ we mean dhyana or contemplation. It is a special type of concentration. In the first place, meditation is a fully conscious process, an exercise of the will. Secondly, meditation means concentration on a spiritual idea which presupposes that the aspirant is capable of rising above worldly ideas. And finally, meditation is done usually at a particular center of consciousness. It is clear that true meditation is a fairly advanced state, attained after long practice.