The historical Buddha refrained from answering many of his students’ metaphysical questions, such as whether a self exists or not, whether an enlightened being continues to exist after death or not, or if the world is eternal or not. This is often referred to as the silence of the Buddha. The Buddha said he was silent on these questions because they didn’t lead to liberation, but instead were a distraction.
The Buddha illustrated his position in the parable of a woman who has been hit by a poisoned arrow. The woman is taken to a doctor, who wants to remove the arrow at once. But the wounded woman cries out, “The arrow shall not be pulled out until I know who the man is who shot me, to what family he belongs, if he is big, small, or of medium build, and if his skin is black, brown or white.” Just as the woman wounded by the arrow would have died before she got the answer to her questions, so the student would be laid low by the suffering of the world before solving these metaphysical questions.
—Paraphrased from the “Silence of the Buddha” entry in The Encyclopedia of Eastern Philosophy and Religion