In the meditative state there are three things: the object of meditation, the process of meditation and the meditator. The meditator is aware of himself and the object, and there is self-direction too. But there is a still higher state of concentration called samadhi, in which the object alone shines so brightly that the meditator loses himself, as it were, being absorbed in the thought of the object and experiences ecstatic joy.
Patanjali thus describes this state: Tadeva arthamatranirbhasao svarepauenyamiva samadhi; In the same meditative state, when the meditator loses himself, as it were, and the object of meditation alone shines forth – that is called samadhi.
There is a still higher state of consciousness where even this single thought of the object of meditation is eliminated and the Self is revealed in Its pristine purity without any qualification.
Swami Vivekananda explains this with an appropriate illustration: The bottom of a lake we cannot see, because its surface is covered with ripples. It is only possible for us to catch a glimpse of the bottom when the ripples have subsided, and the water is calm. If the water is muddy or is agitated all the time, the bottom will not be seen. If it is clear, and there are no waves, we shall see the bottom. The bottom of the lake is our own true Self; the lake is the Chitta [mind] and the waves the Vrittis [thoughts].
The true purpose of meditation is to know our true nature, the bedrock of our personality, by removing the accretions that cover it. This is done in stages, first by holding on to one thought to the exclusion of all other thoughts, and finally letting go of even that single thought. This brief description of meditation in the light of Vedanta and Yoga philosophies is only to highlight the main aspects of meditation which may stimulate one to study the subject further.
Source - Excerpts from article titled 'Meditation According to Hinduism' by Swami Nityasthananda published in the May 2005 issue of Prabuddha Bharata magazine.