Quote"To know, is to know that you know nothing. That is the meaning of true knowledge."
This is a contradiction on its face and all the way down. It is a complete refutation of knowledge as such. The concept "nothing" denotes an absence - in this case, an absence of knowledge, of all knowledge. In order to have language, we need to form concepts and assign words to them, e.g. "know" "you" "nothing" etc. If our concepts are based on observable facts in reality, we call that knowledge (as opposed to faith). If you know nothing, your mind is a blank, a zero, a vacuum, and you have no means of stating that you know nothing.
As to the original question, yes, although the phrase "true knowledge" is a redundancy. Knowledge comes from using our perceptual faculty to observe the world around us, and then integrating what we see into concepts. Sight, touch, hearing, smell, taste... Think of what would happen, what the state of a child's mind would be, if he could not see? He would never be able to form a visual concept, such as the color "red" or even the concept of "color".
Now what happens to a child who is
completely senseless? Some one who is deaf, blind, who can't taste, who can't smell, and has no tactile sensation?
He would have no means, no method of experiencing the world. He might have automatic processes, such as a pulse, and breath, but he would not be able to feel either. His mind would be like a vacuum; ready to be filled at the first sensation he experiences, but unable to experience or to think anything. From the simplest thought to the most complex abstraction, observation of the world via the senses is required.
