When you first begin to meditate, and for some people, quite a while after, you really do need to give the mind numbers, a mantra, or even a visual in order to "ride the bike." A visual during meditation would be something along the lines of the air passing in and out of your nostrils or your diaphram rising and falling, not a visual of being at the beach or a lake (that falls under the category of visualization, which we do prior to meditating during the Tuesday night meditation class).
Just as the tot learns to let go of the trainers on his or her bicycle, the meditator learns to let go of the numbers, mantra, or visual. You may wonder, "Then what is the experience of meditation?" All beginner meditators get a taste of what this is like from time to time. I like to call this state of mind "being." You are just being in the present moment aware of you. The experience is not that different than sitting by a lake and observing it, only when you meditate in this way, you don't have the lake, you tap into the peace and stillness inside of you.
Since meditation is such an experiential activity, it's best not to over intellectualize this. Just try meditating in this way after 10 minutes of concentration on the breath using numbers, a mantra, or a visual, and then see where this takes you...
