This simple observation is the first law of human knowledge, philosophy. Nearly all arguments and many of the puzzles and perplexities of ordinary philosophy are created by a misunderstanding of the fundamental nature of word meanings and by an improper linking together of words in sentences. Words are merely labels on concepts, but some people sometimes confuse words with things or believe that words are somehow directly related to things. They think if they know the word, they know the thing itself. The third law is that words can never say all about anything and that definitions of words can continue indefinitely.
Epistemology is the study of knowledge.
Knowledge ranges from absolute falseness to absolute truth. There exist probability logics for dealing with this infinite range of truth-values. Imagination possesses the lowest degree of truth-value, mere fantasy. But anything that can be conceived by a human being is possible. Fantasy has the lowest likelihood of any human thought of being true.