"By what you see": The visible Form (as-Surah al-Mar'iyyah).

"And by what you do not see": The Pre-eternal (al-Qadim) which senses do not perceive, and which is not conditioned by motion or stillness. And this is a proof of what we have explained.

We observe in existing things many matters that are contrary to how they appear: Among them is the mirage we see in the middle of the day when the heat intensifies; we do not doubt that it is water, yet it is contrary to that.

We look at the mountains while we are in a vast land, and we see them as if they are close to the sky, yet they are contrary to that. And we look at the sea, and we see as if the furthest point our sight falls upon is attached to the sky, yet it is contrary to that.

In existing things, there are matters observed contrary to their reality. Likewise is what appeared of [Divine] Power. Thus, the discourse is established, and the argument is proven regarding the validity of what we have presented. We shall clarify the evidence that has appeared in the Book of Foundations (Kitab al-Usus) regarding this meaning, if Allah the Almighty wills.