The Agnostic believes that the existence of God cannot be proved or disproved simply because this is beyond material phenomena.
Agnosticism is not opposed to a personal faith in a greater power. However, it does not force the human society to follow right or wrong based upon religious rules and rituals.
The logic applied to prove right and wrong starts and ends in the material world. Water flows from higher level to lower level. The opposite is impossible in the material world.
“A person dreamt of a monster last night.” Logic will fail to prove this information. No one other than the person will know if it is true.