The Buddha says:
Is there, bhikkhus, any method (pariyaaya), by following which a bhikkhu is apart from belief, apart from preference, apart from hearsay, apart from methodological argument, apart from reflection on theory, apart from speculation, and fully knows thus: "Birth is ended, noble conduct is established, done is what was to be done, there is no more of further becoming" ?

... There is indeed a method ... And what is that method?

Herein, bhikkhus, a bhikkhu, seeing a visible object with the eye, either knows the existence of desire (raga), hatred (dosa), and delusion (moha) within him, thus: 'I inwardly have desire, hatred, and delusion' , or knows the non-existence of desire, hatred, and delusion within him, thus: 'I inwardly do not have desire, hatred, and delusion' . Now, bhikkhus, I ask: As to that knowing the existence or non-existence of desire, hatred, and delusion within him, are these states (dhammaa) to be known (veditabbaa) by belief, or preference, or hearsay, or methodological argument, or reflection on theory?

Surely not, venerable sir.

Are not these states to be known by seeing (disvaa) with wisdom (pa~n~naaya) .

Surely, venerable sir.

Again, as to hearing a sound with the ear ...