We are living in a field of energy, vibrations. Within that field, there are areas of energy concentration like lumps in oatmeal. We will call them “Nodes”. Those nodes vary is size, energy level, frequency, etc. but are really very similar and, if we say them as they really are, we would know that. But we don't see them as they are. 
    First, quantum mechanics tell us that when we look at something, the simple act of observation changes it. And “observation” doesn't have to mean looking at it directly with our eyes. It can be “observed” with a camera, a sensor, a radiation detector, etc. Then when we look at the image from the device in whatever form it takes, we make an indirect observation. 
    In either case, we don't see swirling masses of vibrating energy, even though that is what is there. We see a person, a dog, a tree, a rock. We see the material objects that we are so familiar with. And what we see is determined more by what we expect and what we believe than what is actually there. We learned at an early age that nodes of a certain size, frequency, and energy level had a certain meaning. But it is all just the interpretation by our brain. And our brain can be fooled.
    When Columbus first landed in North America, most of the natives were unable to see his ships! They may have been aware to some degree that there was something there, a disturbance in the water, a strange energy; but they had never seen ships so their brains had no way of translating the node of energy into an object so it was simply invisible to them! Then the Native American shaman or witch doctor, whose knowledge of spirit allowed him to see better that the others, described the ships to them since he could see them. Once they had been described, the rest of the natives were able to see the ships as if they had suddenly appeared out of nowhere!
    So before we make any rash statements about knowing everything, nothing left to learn, if it existed we would know about it, it can't be real if I can't see it, etc. consider those Native Americans and then realize that there are probably many energy nodes around you right now that you don't see because you have never been told about them and don't expect to see them, or you were told when you reached a certain age that they were imaginary so you should stop seeing them, whether they are there or not.