Tafsir of An-Najm 53:35

The particle fa (so) in the words of the Exalted, "so he sees," is for causation relative to what precedes it. That is: Does he possess the knowledge of the unseen, so that by virtue of that, he knows that his companion will bear on the Day of Resurrection what he fears for him?

It is said: He sees that what he heard of the Qur’an is falsehood. Al-Kalbi said: The meaning is, has a Qur'an been revealed to him, so he sees that what he has done is the truth? Whichever the case, "sees" here is from heart-based vision (ru’ya qalbiyya). It is also permitted that it be from visual sight (ru’ya basariyya), meaning: he perceives what is hidden from others, from that which is of the unseen.