**We cannot know anything with absolute certainty; maybe even the famous "I think, therefore I am" could be uncertain in some ways, too.** - René Descartes famously [said](http://faculty.winthrop.edu/sinnj/HMXP_102/Readings/Rene_Descartes.pdf) "I think, therefore I am," by which he meant to expound the notion that absolutely everything in the world could be uncertain, yet one can still be certain of one thing: That they are thinking/experiencing the _something_ of this moment. I.e.: Whatever experience one is having in the current moment, to whatever extent, is the sole point of pure certainty; the thinker's existence in each particular moment they feel is the only thing of which one can truly be certain. Anything beyond that---the validity of the external world, the content of the external world, the existence of others---has to be based on some kind of faith. - I sometimes wonder if even this could be doubted just a slight bit. If "I think, therefore I am" means my existence is at the very least whatever the thinking is, it covers everything imaginable; there's no need to know _what_ I am, only _that_ I am. But this knowing _that_ I am---being (_somehow_, but ultimately literally just _being_) the flicker of experience at each moment whose defining characteristic is the only certainty for each current time---requires something to understand itself, itself, because of just that: It has a _defining_ characteristic. What I mean: - There is some kind of existence for us in the fact that we feel something; that feeling might be "all" "we" "are" but we _know it's a state of something_ nonetheless. To me, that _could_ be a small leap beyond: That second part of us knowing that there's a state of somethingness to the idea of us feeling something. This second part seems to require a secondary, super- proposition we, conceivably, almost shouldn't have: Knowing that the "all that we are" is a state of _something_. I could imagine a "purer" world in which we just _were_, without having that element of feeling that, or sometimes what, we are. - Of course, this is precisely what Descartes meant to cover: Any of this "imagining a purer world where, etc." is irrelevant to the singular moment of feeling and thinking that one is somehow existing as or deriving their existence from; one literally just has/is whatever that is, in whatever that way might possibly be, no matter what. I'm only wondering here whether there isn't already an "extra" type of being implicit _in this being_ each time we "are" it. Us knowing and feeling this one certain experience of thinking might already have or require all kinds of extra feelings and thoughts _about_ it to enable it to, for instance, _know_ that it is just a thought or feeling, when it feels that it _is_ that state _of_ "being a state of a thought or feeling in that moment" _in that moment_. Perhaps your feeling of the moment cannot be an isolated occurrence precisely because you feeling it automatically gives you context to layered assumptions, even about the very premise itself. (Many apologies for the obscurity here---it can get quite difficult for me to narrow in on things that sometimes elude language.) - This, then, might mean we can have certain premises we just know---that we come built in knowing, in a sense. Because we are entangled with all this in a way that enables us to even have the thoughts of "I think, therefore I am," there might necessarily have to be something else we know beyond it for it to have ever gotten "it, its own self" out there in such conceptions as "our being that follows from just what we feel in the moment is a _something_ instead of not being a thing at all," if that makes sense. - Or this may ultimately be subsumed within and for each person's singular experience. Ultimately, I do think the famous phrase stands its ground no matter what, so I have to remain mixed here. I can't go all the way to doubt the one certainty of existence as put forth by Descartes, because ultimately it is so excellent and watertight, but I do wonder if it itself can't be questioned in some small way at its foundation.

**I agree that we can't truly know anything with absolute certainty. Theories that have a scientific basis are the closest we can get to a sense of objective knowledge.** - 'Knowing things with absolute certainty' = having no doubts whatsoever about something. It is, in its pure sense, impossible because of [the extremely limited range of human perception] (https://cognitiontoday.com/psychophysics-sensory-and-perceptual-limits-the-human-umwelt/). - Despite this - [science] (https://en.wikiversity.org/wiki/Does_objective_reality_exist%3F) does provide amazingly consistent evidence of objective knowledge. For example - we as good as 'know with absolute certainty' that evolution took place. This is because the theories that we've formulated around it [have stood the test of time] (http://www.bbc.co.uk/earth/story/20150803-how-do-we-know-evolution-is-real). But - as long as any idea of objective and absolute knowledge depends on human perception, it will to some extent be limited and not provide us with an 'absolute certainty'.

**TL;DR -- The problem with this statement is the word "anything."** I am absolutely certain that I have a face. I can see it in the mirror, touch it with my hands, and feel it when it gets punched. I am absolutely certain that I need food to live. When I don't eat, I lose energy. When other people don't eat for long enough, they die. And I am absolutely certain that I do not want to die. And, I am absolutely certain that pain hurts. When I touch a hot stove, it burns. When I get hit by a brick, I go "ow." When I step on a lego, my very soul shatters. ... Point being, if there aren't a *few* things in life that you can be 100% sure about, then you're probably doing something wrong.

**Problem of induction - we can never really know for sure!!** - If I can remember this correctly (it's been a long summer) we can never truly prove anything. Not really anyway. There is the [problem of induction](https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&cad=rja&uact=8&ved=2ahUKEwiHh5SNitfyAhVgRkEAHb0GDq8QFnoECAYQAQ&url=https%3A%2F%2Fplato.stanford.edu%2Fentries%2Finduction-problem%2F&usg=AOvVaw2t6-j7C0UBgll_kC_OiWi0) - science is based off induction which cannot be justified. So science cannot be justified in return. However this is a whole other point. - We may state that metals conduct heat, but how do we know? Because all the metals that we have *found* conduct heat. However there could be metals we haven't found. My point is, how do we *know* that we have found all the metals? - Very simply, we don't. We don't know. So, we can never be 100% sure of anything.

**If this is true, does it mean we can be absolutely certain that we don’t know anything with absolute certainty?** The arguments made before me still have me mixed on this opinion, as there are good points made on both sides. However, I wonder if this statement could ever actually be 100% true. I think @JenReneeGilley brings up a good point about the word “anything”. If we state that we cannot know anything with absolute certainty, doesn’t that imply that we *know for certain* that we cannot know anything with certainty?

I am certain of somethings that are true because the evidence is overwhelming, I depend on it day to day, minute to minute and it has never been contradicted; not once, even for a second. This creates the feeling of 100% certainty within me. I am certain I that i have hands and the hands I am thinking of are mine. I know they are mine as they always respond to me desires and instructions. I can see them do this if i choose to. They are certainly 100% real. My certainty is an emotion I feel without contradicting emotions. Other parts of my body I have less evidence to prove they are mine and exist, as I have seen them less and "feel their movement" rather than can see it as well as feel it, as is the case with my hands. Could I have imagined them? Are they only false memories from some strange dream world. It might be possible to talk me into the idea that my face (which i don't see that often) or my legs (usually under some desk, or walking/moving below) are some computer generated sensation. But the same argument would not sway me with my hands. I concede that scientific evidence, when trying to prove a fact, only gathers evidence that can be interpreted with degrees of certainty. The nature of science is that no matter what the evidence, it is still open to re-interpretation when other evidence arises that seems to contradict the laws previously accepted. But my hands, I am absolutely certain they are mine and exist.