John 18:37-38 ESV
Then Pilate said to him, “So you are a king?” Jesus answered, “You say that I am a king. For this purpose I was born and for this purpose I have come into the world—to bear witness to the truth. Everyone who is of the truth listens to my voice.” Pilate said to him, “What is truth?”
After he had said this, he went back outside to the Jews and told them, “I find no guilt in him.
Pilate did not know truth because he did not listen to Jesus. The word is there for all, but not all will listen.
Anyone who asks "what is truth" has not received the truth, even when it is revealed. The darkness of deception obscures the light of truth. One who is left in the dark will remain in the darkness. In the end they will understand the truth, but the truth will not set them free.