Cognitive scientists, like Professor Dan Simons of Illinois University, have documented what's called "inattentional blindness:" we spend much of our existence in a kind of daydream, failing to notice the subtle changes occurring in our perceptual field. Show someone a photograph of a building, have them look away for a moment: when they return to what seems to be the same photograph, most won't notice that a large tree has been removed via photoshop. We believe we're aware of change, but much of the time it has to be inescapable before we notice; we are overloaded with stimuli.
Now consider this: For a very long time people believed that each individual owned a unique soul, a lasting "me," an identity or persistent observer of life that lurked at the core of the mind. This belief was based on appearances rather than close observation, similar to how the Sun appeared to revolve around the Earth (it required close observation by Galileo and others to prove otherwise).
The buddha was the first thinker to challenge the predominant view of a consistent inner identity. With the discerning insight of one who spent years engaged in exhaustive self-observation, he saw through the illusion: no consistent, uniting identity could be located in the mind.
The mind in his view was more like a river: with close examination, he noted that the thoughts, moods, feelings, body sensations flowing through our awareness were in constant flux. Even the habits and tendencies that created the illusion of a core personality were undergoing subtle, continuous transformations. Our grasping for an underlying self ("sakkaya-ditthi" in his language) was planted via inattentional blindness, and nurtured by a fear of experiencing our internal changes and unreliability.
2,500 years later science has caught up with the Buddha. Neuroscientists cannot locate any region of the brain that could provide a "persistant observer." That continuous "me" that appears to experience life is even called a "grand illusion." But there is no reason to view the new dawn as fearful; this means we are not chained to or limited by any mysterious self awaiting discovery. As neuroplasticity demonstrates, the brain can rewire itself, we can override even the most hardwired tendencies with compassion and practice, for there is no core identity standing in our way, pulling us back to suffering.