Yes, we can plausibly know at least some things, although whether we can possess absolutely certain knowledge remains disputed. Radical skepticism challenges many knowledge claims, but it does not conclusively establish that knowledge is impossible.
A standard account defines propositional knowledge as justified true belief: a person knows that a proposition is true if they believe it, it is true, and they have adequate justification. Problems arise because perception, memory, testimony, and reasoning may all be mistaken.
The skeptic strengthens this concern by proposing that our experiences could be systematically deceptive. Descartes's dream argument suggests that experiences while dreaming may be indistinguishable from waking experiences. His evil demon hypothesis then imagines a powerful deceiver manipulating even apparently obvious beliefs.
However, doubt itself may reveal one indubitable truth. Descartes argues that if he is doubting, he must exist as a thinking being: cogito, ergo sum ("I think, therefore I am"). Even a deceiver cannot make him think without his existing in some sense.
| Position | Answer to the question | Main issue |
|---|---|---|
| Global skepticism | No knowledge is securely justified | It may be self-undermining if the skeptic claims to know that nothing can be known |
| Foundationalism | Some basic beliefs provide foundations for other knowledge | It must explain why foundational beliefs are trustworthy |
| Fallibilism | Knowledge is possible without absolute certainty | A belief can count as knowledge even though revision remains possible |
The common misconception is that knowledge must equal complete certainty. Fallibilism rejects this: strong evidence and reliable justification may produce knowledge even when error is logically possible. This allows ordinary and scientific knowledge while recognizing human limitations.
In an IB Philosophy response, define knowledge and skepticism before presenting arguments. For an evaluate question, compare the strength of skeptical scenarios with responses such as the cogito or fallibilism, then reach a justified conclusion about whether certainty is necessary for knowledge.
