The word meditation is used in so many different ways that I want to be clear before going further. Meditation here is not reflection or any kind of discursive thinking. It is pure concentration: training the mind to dwell on an interior focus without wandering, until it becomes absorbed in the object of its contemplation. But absorption does not mean unconsciousness. The outside world may be forgotten but meditation is a state of intense inner wakefulness.
It is consciousness itself, which means that all the senses close down.
– from The Upanishads, by Eknath Easwaran, pages 26-27