Alpha is the brain wave belonging to that part of your brain that deals with scope, spiritual as well as physical. It pieces it all together, makes sense of it, or tries to, and listens to the subconscious, where the real story is always recorded. Meditation is done in Alpha, and hypnosis, and sleep, where dreams emerge. All this deep understanding of the nature of the world is resisted by yet another part of the brain, that supported by Beta waves, considered the brain waves of the wakeful and alert, intelligent human. Beta supports the physical existence of humans, by processing what the senses perceive and sharing this with the rest of the brain.
Beta is grounded.
It wants not to know of the deeper meaning, of connections, or what the spirit knows, it wants only to be here and now and can't be bothered with all that other nonsense. The Beta brain helps a creature get through the day, find enough to eat, and escape the flood or fire. It says, in essence, no time for day dreaming now, we've got survival to worry about. That's why the Alpha brain takes over at night, when the creature is safe, and has time for such nonsense as the riddles that the Universe presents.