Stative vs dynamic verbs

(1) ?John is knowing the answer.

The ? indicates oddity, but why does the sentence sound odd? Grammatically, the sentence seems fine if we contrast it with (2) below:

(2) John is painting the house.

Both have the same structure of a present progressive, but why is (2) a possible English sentence but not (1)?

The answer lies in the difference between stative and dynamic verbs.

Stative verbs are verbs that express a state. This state or condition is relatively stable and homogenous through time, and can be conceptualized as being contractable or expandable.

Dynamic verbs, on the other hand, are verbs that describe an action. This action normally involves some change of state and has a limited duration or a well-defined beginning and end.

The difference is an important one.

A dynamic verb in the present progressive, such as painting in sentence (2), can signify an on-going activity coinciding with present time.

A stative verb such as know, on the other hand, cannot normally be marked progressive. Being indefinitely contractable or expandable, it is easily accommodated by the present-time frame:

(3) John knows the answer.

And therefore the progressive aspect is redundant, which explains why sentence (1) is odd.