If asked what are you aware of, you might identify the present things you see, hear, feel, and so on. These change all the time with our shifting attention and with our physical movement. However, we can ignore the identifications of objects and simply notice that what we are aware of all the time is the changing contents of our senses and mental processes. We are aware of everything we can name by means of vision, sound, bodily sensation, our mind (thoughts, memories dreams etc), and the other senses.
This is our universe of experience, this is everything we know directly. The Buddha called this “the All” (Itivutakka Ch1, 7.13), and at other times he divided the All into five categories or aggregates, the skandhas. The realisation that, in effect, we are nothing but this, in meditation or at any time, is an important basis for insight into our true nature.
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A good exercise is to sit still and notice each of the senses in turn, becoming absorbed in each one, free of thinking as much as possible. As for thinking and mental events, the key point of this particular exercise is simply to be aware that there are mental processes, and they are a part of our experience.
We need to watch carefully what happens when turning our attention to thinking itself. It is important not to allow thinking to divide our experience, making the assumption that thinking is looking at the other senses. This easily slips into imagining that we are our thinking and that thinking experiences the other senses. When we realise the All, we notice that our awareness includes mental events such as dreams or daydreams in an equal way to other senses.
Awareness is just Awareness
Rather than seeing thinking (etc) as being different from other senses, it is helpful to question, how much is it the same? Is sound any more substantial than thought (just sound, not what we imagine made the sound)? We conceive of a body, but what we actually experience is sensations: are those sensations more substantial than thought? Pursue this line of questioning, relying totally upon direct experience.
Becoming certain that the totality of our experience is the All is a beginning, a start which leads onto further clarity.
Pieces of Five 