Good suggestion. That is exactly the place to start. I have given this question some thought when I was having a conversation with Moving Finger at
https://www.physicsforums.com/showthread.php?t=64156&page=9
(if you read this, be aware that PNS = Physical Neurological System = biological body).
The conclusion I reached in that discussion was that while qualifying the term 'knowledge' by saying 'certain knowledge' is redundant, it nonetheless emphasizes the question of what knowledge is. Indeed, it raises the question of whether any knowledge can exist at all if it must be certain. How can anyone be certain about anything? I think it is not possible. So what does 'knowledge' mean if the known "facts" are not certain?
I think the only way out of this is to consider knowledge to be characterized on a scale from, say, 0 to 1, where 0 means it isn't knowledge at all, and 1 means certainty. Then "facts" would fall near the upper end of the spectrum even though none would be exactly on the 1. Thus we could have useful and fairly reliable knowledge without requiring certainty. The foundation would be at least as firm as what we build houses on.
I agree. But I would point out that you have qualified 'knowledge' by restricting it to "human knowledge". It leaves open the question of the existence of a knower other than humans which might have a very different basis for knowledge.
There are a few assumptions buried in this claim. First of all, the meaning of 'we' isn't clear. Of course the tacit meaning is the collection of humans involved in this discussion. But in my view, I don't think the perceiver, in the sense of the conscious awareness of the perceptions, is necessarily confined to the brain. So when we talk about what "we perceive" we might be talking about the information that can be reported by a biological body, or we might be talking about some other entity (my PC or PATK) separate and apart from the body.
Another ambiguous term is 'reality'. Since so many people assume that reality consists of nothing more, or beyond, the physical universe, we are left with no term to describe anything that might exist in addition. So, I would suggest saying, what we humans report perceiving is physical reality. I also suspect that what PC perceives via information from a particular brain on a particular world line is largely a portion of physical reality informed by that particular POV. Further, I suspect that PC may perceive things outside of physical reality even though he/she/it might do so via information from a particular brain (say Les Sleeth's) on a particular world line (say during one of Les's meditation sessions). In short, I'd say that reality is much greater than what is conceived by scientists to be the universe.
Amen! (So to speak) I think that happens in spades. In particular, I think any access to non-physical information as reported by humans is always so distorted and unreliable as to be nearly useless. To wit, all the religions of the Earth and the confusion, error, hostility, devastation, and error they have wrought in trying to interpret their respective revelations.
I agree. Science, and in particular mathematics, has set the standard for deriving knowledge from what we can perceive.
I suppose you might be right. But this wild speculation is still a lot of fun. Moreover, I think that at least some progress can be made strictly by using logic and exploring the implications of some unconventional hypotheses. And, as I keep saying, it seems to me that the implications of assuming the existence of only a single consciousness leads to a framework which not only accommodates all the explanations of science, but also all of the mysterious behavior of human beings as well.
Thanks for your thoughts,
Paul