The word nihilism is a noun. It is a philosophical term meaning extreme skepticism.

Jeffrey P. Whitman has written:

'The power and value of philosophical skepticism' -- subject(s): Knowledge, Theory of, Skepticism, Theory of Knowledge

One philosophical method that specifically addresses falsity in its various forms is the method of skepticism. Skepticism questions the validity and certainty of knowledge claims, examining the possibility of falsity in beliefs and perceptions to arrive at a more nuanced understanding of truth. This method encourages critical thinking and inquiry into the nature of truth and reality.

Metaphysical certitude refers to the highest degree of certainty one can have about metaphysical or philosophical propositions. It is reached when no possibility of doubt or error remains about a particular truth or concept within the realm of metaphysics. It represents a level of conviction that transcends skepticism or skepticism.

Skepticism maintains that knowledge is impossible to achieve and truth is impossible for man to understand.