In Buddhist psychology, consciousness is thought of as a "sixth sense" and is therefore, like our other five senses, an organ of perception and misperception. Manas is the energy associated with consciousness, and this energy is characterized by a craving for identity; particularly a separate sense of self. Manas is constantly engaged in the calculation of defining what is and what is not "I" and ultimately is the progenitor and generator of our dualistic subject/object perspective.
This attentiveness to "I" leads to moment to moment generation of a sense of egoic separateness that causes experience to be perceived as personal: "This is happening to me, in me, around me, because of me, in spite of me, etc." It is truly remarkable how we assume without question that we are our perceptions, thoughts, and feelings and that these perceptions, thoughts, and feelings are the ultimate empirical definers of reality. Descartes' famous pronouncement, "I think therefore I am" is emblematic of this way of defining identity.
Neuroscience has been hard at work trying to understand the process of cognition and identity. Yet for all their efforts so far they have only confirmed what the Buddha taught 2500 years ago about the nature of self: there is no actual self to be found anywhere in the human mind or brain. In fact, finding the mind itself has proven equally elusive. Our concept of self seems to be constructed in each moment of experience through a complex process of perception, recognition, categorization, and reaction. Though our states of mind continually shift, the conceptual sense of and identification with an "I" as the owner of emotions, thoughts, sensations and experiences remains intact.
Given these facts, one might wonder about the insistence of western psychology on caring for the self. More on this later!