We use the present simple to talk about things and situations that are generally true

Stative verbs
Some verbs are not usually used in the continuous. They are called stative verbs, and are: verbs which describe thoughts, feelings and senses: think, know, believe, agree, remember,
forget, understand, like, love, hate, mind, prefer, want, see, hear, smell, taste. So we do not say: I’m knowing the answer or She isn’t understanding anything. We say: I know the answer. She doesn’t understand anything.
We use can with sense verbs. We do not say: I’m not hearing you. or I don’t hear you.
We say: I can’t hear you.
some other verbs which describe what things (and people) are, what they are like, and
what they possess: be, have, need, own, involve, depend on, seem, look, sound, smell, taste, weigh. So we do not say: I am being hungry. or This soup is tasting nice. We say: I am hungry.
This soup tastes nice.
But some of these stative verbs can be used in the continuous sense. Compare She’s tasting the soup (her action) and The soup tastes good (what the soup is like), and What are you thinking about? (what are your thoughts?) and What do you think? (what is your opinion?).

1.1In English grammar, a word class is a set of words that display the same formal properties, especially their inflections and distribution. The term "word class" is similar to the more traditional term, part of speech. It is also variously called grammatical category, lexical category, and syntactic category (although these terms are not wholly or universally synonymous).The two major families of word classes are lexical (or open or form) classes (nouns, verbs, adjectives, adverbs) and function (or closed or structure) classes (determiners, particles, prepositions, and others).

"When linguists began to look closely at English grammatical structure in the 1940s and 1950s, they encountered so many problems of identification and definition that the term part of speech soon fell out of favor, word class being introduced instead. Word classes are equivalent to parts of speech, but defined according to strict linguistic criteria."(David Crystal, The Cambridge Encyclopedia of the English Language, 2nd ed. Cambridge University Press, 2003)
"There is no single correct way of analyzing words into word classes...Grammarians disagree about the boundaries between the word classes (see gradience), and it is not always clear whether to lump subcategories together or to split them. For example, in some
Grammars, pronouns are classed as nouns, whereas in other frameworks...they are treated as a separate word class."(Bas Aarts, Sylvia Chalker, Edmund Weiner, The Oxford Dictionary of English Grammar, 2nd ed. Oxford University Press, 2014)