I can being doing something and not be aware that I am doing it; I am not conscious of what I am doing. In other words, my nervous system can be directing and coordinating a behavior while I am blissfully unaware of it. In some cases, I can potentially become aware of my unconscious behavior. And when I do, I typically get more voluntary control of that behavior. Take breathing, for example. Most of the time I am unaware that I am breathing. When I do become aware of it, I can control it to some degree. Sensory systems can potentially transmit information without any conscious awareness of that information; that is, unconsciously. But when we become aware of what a sensory system is doing, whether by accident or intention, that sensory information becomes conscious. It seems, then, reasonable to claim that consciousness is awareness of awareness. For example, how does the big toe on your left foot feel right now? Before I asked, that sensory awareness (information) was available in the system, but unconscious. You were not aware of it. Once asked, you directed your attention to that sensory information, became aware of that sensory awareness, and it entered your consciousness.