How is anything known

However, it seems to become infinitely pun intended problematic if one thinks about it deeply enough. For instance, if one knows with absolute certainty that one does not know anything with absolute certainty, then one must also know with absolute certainty that one knows with absolute certainty that one does not know anything with absolute certainty. I think that one knows where I am going with this. It could be extended ad infinitum.

If one, however, accepts that one does not know with absolute certainty that one does not know anything with absolute certainty, is it still self-refuting or contradictory. My point is, our perception is limited by what we can see two-dimensional image of a narrow range of photons , hear short range acoustical signals , feel, smell, and process with our inherently ambiguous and limited language. So, in effect we are limited to reasoning about models that we make of the world.

That is how most of science works anyways, and the goal is to expand the model to make it as close to the real world as possible, while still allowing us to reason properly.

Yes it is possible, but then that part of your life becomes dependent on that assertion. This is why there are axioms and logic which survive over time: they simply become the status quo which is defended for various reasons: ultimately for either practicality or aesthetics.

Beyond that one can only know of one's existence. Because to know anything means to exist. That is the starting point, the basis for philosophy. I believe this is where the ugly but necessary bridge between Continental Philosophy and Analytic Philosophy is very necessary.

Although, given a set of axioms, prove rigorously the existence of certain truths, we explicitly rely upon the ontologies presented within the axioms in order to make any claims to truthfulness. Take for example what Eliran writes:. How do we know that we have this bag? We rely explicitly upon a world of phenomena, limited to our own perception, and uncertain of the extension of that perception to any sense of universality. There is an implicit ontology of "having", related ultimately to the "being" of these black marbles.

There is a Cartesian instability to that existence, but we cannot rely on God's willing hand to move things back into place like Descartes did. Rather, we must move to the assumption that the bag does exist, but keep in mind that this assumption works not in any universal sense but rather in our own "lifeworld" this is from Husserl's Crisis of the European Sciences.

We cannot know that these black marbles exist in any universal sense, but we can observe that in our world, that they do exist. This is not relativism - this is bracketing universality not to the world, but to all experiences of the world. Thus, that we draw only black marbles does not serve as a universal truth because can we know with certainty of the a priori world outside of our experience? This is kind of leading all up to Habermasian communicative rationality, but I'll leave you to research the topic though I don't recommend it particularly as a model for political-moral norms, it works perfectly well as a model for scientific rationality.

Why does the human make these errors in logical deduction? Is it not simple, if given a set of axioms, that the conclusions may follow beautifully into place? On any particular occasion a person either makes an error or doesn't make an error. And errors arise from false ideas about what's going on or from mistakes about some particular fact.

They don't arise randomly and don't arise just from deduction. A better question is "How is it possible to create knowledge given that we might be mistaken about anything we think is true? Knowledge is information that solves problems. Knowledge is not guaranteed to be true or probably true or anything like that. We create knowledge by conjecture and criticism. We notice a problem, something about our current ideas that seems worth fixing.

We then guess about how to fix the problem. We subject the guesses to criticism. Does the guess solve the problem we intended to solve? Does it conflict with other ideas and if so should the new idea or the old one be discarded?

Does it conflict with experimental results? You keep criticising the guesses until only is left and then look for problems with that guess. For that matter the local part of the Universe might be a statistical fluke that popped into existence 1 millisecond ago, so that your apparent memories etc.

The chance of something like this happening is fantastically low, but not zero, hence you can't ever be absolutely sure about anything. In the Bayesian interpretation of probability , probability represents subjective belief. But a bayesian reasoner in the real world must consider the possibility of errors, deception, or even crazy hypotheses like false memories. It must attach probabilities to all beliefs, and consider all hypotheses. Humans are certainly not perfect.

We make mistakes all the time. Can you really be sure about things in mathematics? Well published mathematical research is shown to have errors all the time. Everything is probabilistic. Nothing, not even math, can claim to be infinite certainty. How certain are you that 51 is a prime number? P1: If, we can claim that things in the universe are a certain way with absolute certainty, then we must have complete knowledge of the thing.

P2: If we have complete knowledge of a thing, we have to have complete knowledge of the universe in order to understand the thing completely. All proofs or arguments deductive or otherwise are finite; if they weren't, the conclusion could never be reached.

They rely on premises, and those premises, forming the basis for the argument, are unproven. You could create a proof of those premises; but that new proof would in turn itself rely on unproven premises.

So the problem is inescapable. Ultimately, all deductive reasoning depends on premises that aren't deductively proven. Arguments often also rely on auxiliary premises that aren't explicitly present. They are background assumptions.

Premises fall into three categories: arbitrary premises, like those chosen for an abstract formal system; provisional or working premises; and self-evident truths. Since arbitrary premises are stipulated, and provisional premises are uncertain, we can move on to the directly apprehended, or self-evident, truth.

This could be something experienced, like consciousness, or it could be something relying on intuition or some other form of understanding. Sometimes, however, things taken to be "obvious" or self-evident are dependent on auxiliary premises that needn't be true, or are otherwise only provisionally true.

Provisional truths can be changed to provisional falsehoods and vice-versa by additional data, for example. The problem is complicated by two additional, often overlooked factors: the circularity of definition; and the fact that statements only have truth values if they are sufficiently well-defined.

In order for a statement to be well-defined, each individual term must be well-defined. Also, of course, the words must be put together in a meaningful way. Every dictionary, no matter how technical or comprehensive, contains a finite number of terms. So, every definition, using terms in the dictionary, must point to other terms in the dictionary, which in turn point to other terms in the dictionary. Eventually, some of the definitions must point back, circularly to terms original or intermediate that one is trying to define.

The true meaning comes from personal associations or apprehensions attached to terms. For example, "red" means something to me not because it is defined as a mixture of other colors or as certain wavelengths of light, but because I have seen objects to which the term has been applied.

As for truth values, they can't be assigned to obvious nonsense. But what about statements that seem to be talking about something, but involve fuzzy conceptualizations or poorly defined terms, or contradictory elements?

Geometric points are said to have no spatial extension yet somehow occupy and indicate position within space. Real numbers contain a never-ending series of digits that are nevertheless said to form completed entities in their "entirety". If there is space between them they aren't touching. And if there isn't space between them they must be spatially coincident, which is to say they must partially occupy the same space simultaneously.

Except that because of quantum fuzziness, objects made of atoms with orbiting electrons don't have clear borders. And because of special relativity, simultaneity means something different to observers in different frames.

And time is subject to quantum uncertainties. And mathematically precise position ultimately comes down to geometric points, which are nothings pretending to be somethings. Sign up to join this community.

The best answers are voted up and rise to the top. Stack Overflow for Teams — Collaborate and share knowledge with a private group. Create a free Team What is Teams? Learn more. Is it possible to know anything with certainty?

Ask Question. Asked 8 years, 1 month ago. Active 4 years, 6 months ago. All are subject to deterioration; all reintroduce the past into the present; and all are subject to the interactive effect of deterioration and reintroduction. Memory in particular is the most vulnerable because it is a biological system and therefore less stable than for example, a photograph.

Photography however, although being less obviously vulnerable, is subject to developing technology and the prevailing perceptions within that technology. It is easy to date photographs within a reasonable span of time. Photography, unlike memory, is external to the self and therefore is also part of the substance of the material world. None of them will hold their form beyond a very limited period, and they will then be subject to the vicissitudes of historical interpretation.

The probability of a simple world producing sophisticated thinkers is vanishingly small. So the world is complicated. A being that is sophisticated enough to think about these things will be fragile enough to need a good idea of what is going on in order to survive in a complicated world thermodynamics. Now, either this thinking and being is independent of the physical world or it is not. Unforetunately, philosophers can generate rational accounts and justifications to order.

So we philosophers have the stone by which true belief may be transmuted into knowledge, but it is unreliable. Finally, if the physical world does not exist then I did not read the question in Philosophy Now.

Descartes thought he had a definite certainty in the cogito — what could be more certain than the existence of the self? In truth, all we can have certainty of is that there is something.

We are constantly bombarded with the certainty that something exists. With every glance, sniff or touch we are obviously and indubitably aware of the existence of something — indeed the fact is forced upon us. If you had to relay the request, you could substitute one phrase for the other without the person being disappointed by the eventual choice of book. Generally, an unspecified thing is a thing with no specified type or kind, and thus could be said to be a thing of any kind — ie, anything.

Therefore something and anything are logically equivalent. So, if the existence of something is certain, then the existence of anything is also certain, and therefore we can know that there is anything as long as it is not nothing — even if we do not know what anything is.

The only way I can know anything is by the knowledge given to me by someone or something else. This can happen by learning from my parents, my society, everything I come into contact with from the day I was born until the day I die. This is why two human beings who live in a completely different part of the world like the USA and a remote village in Africa have completely different knowledge about everything and anything.

All the knowledge that we have was giving to us by someone else. Therefore our knowledge can never be truly objective. Is it no coincidence that we are all become our parents. People never know things, they only subscribe to hypotheses with more or less commitment.

It would seem that to assert that x exists is to subscribe to a theory involving x. Given the possibility that I am a Martian Sandmole dreaming this while in my burrow, I have to ask what precisely the x could or must be that is experiencing. For any possible x there will be some degree of commitment to it as being the correct value.