Looking in front of you, what do you see?
But some much else appears in your field of view
Most of day to day work of since is separating signals from noise. Until you subtract out everything else that can produce the same effect. You simply can not denied until you get rid of the noise
Your brain must reject these distracting intruders
It's the same way you must reject all the other radio stations when you tune into this one.
Even if you could get them all at once you would hear nothing but noise
Rejecting the information you do not want to focus on, what you do want