So the next step here is to provide justification for what is knowledge. How does something become known? Is seeing believing, or knowing, or neither? Can it be neither? It should be information, most certainly. How that information is processed depends on the capabilities of the individual. Perception, however, “is the organization, identification, and interpretation of sensory information in order to represent and understand the environment” - a very apt definition. It is critical to knowledge, but is it all that is necessary for something to become knowledge? Please note that perception in this sense, and sight, are two different things. Sight is used in perception, but something far more important occurs in organizing, identifying and interpreting the sensory information of sight. What occurs tells us our abilities as humans, our limitations. If I see a tree, does that mean I know the tree is there? It depends. I’ve seen trees before that weren’t there. How do I know? Because they were proven to be hallucinations. In a world in which things aren’t what they seem, it isn’t necessarily the world’s fault, but is the limitations of our “sight”.
We see things based on our subjective ability of our sight. Human eyesight is fairly similar from person to person, as say, compared to a snake that sees in infrared. https://en.wikipedia.org/wiki/Infrared_sensing_in_snakes
Who is objectively seeing a tree, a snake, or a human? Of course, neither. There is no reason why the processing of light reflected from an object is more accurate to the identity of object, as opposed to the processing of heat emitting from an object, is to the identity of an object. Even still, we do not base our perception off of sight a lone. We do not even process sight as a sole percept that we can consciously perceive without the other interference from our natural cognitive processes that lead to perception. We may not even know what eyesight is that is unfiltered from all the processes that occur during perception. Not only can the health of our body affect what we “see”, so to speak, or rather perceive, but our biological make up and our experience combines to produce the totality of everything we use in perceiving things with sight. What that can lead to are great variances, unknown variances even in person to person. People can sometimes even, see what they want to see, which can be seen as a form of confirmation bias, in so much as there is “selective perception” as well as even seeing things that aren’t really there because of what our mind might seem normal… or seeing aspects of things that aren’t really there because of many numbers of factors that occur during perception. So why not take what you see even, with a grain of salt? Perhaps its too difficult. Perhaps it must be how you want it to be. Perhaps you aren’t capable? Perhaps you think its not possible. Or perhaps you do.
So is sight alone a qualifier for knowledge? No, it is not. But then again, we never really ever use sight alone. It’s always perception, its always processed, and presented into our consciousness based on unconscious processes that naturally occur.