Have you ever observed a river closely? The river flows quite strongly and at that time you cannot see the riverbed clearly. In such a situation if there was some way you could stop the flow in both the directions, ie from where the water is coming and to where the water is flowing, then may be you could keep the water still. This would help you see the base of the river quite clearly.
Similar is the case with our minds. All you need to do is stop your mind from chasing sensory objects as well as thinking of the past and future and that is specifically the time when you can completely free your mind from being totally ‘blanked out’. It is this time that you will have a clear view underneath this turbulence of the thought processes. There is an underlying stillness as well as an underlying clarity of the mind. It is essential that you observe or experience something like this.