Charles Ellicott Commentary Isaiah 40:21

"Have ye not known? have yet not heard? hath it not been told you from the beginning? have ye not understood from the foundations of the earth?" — Isaiah 40:21 (ASV)

Have ye not known? ... —Strictly speaking, the first two verbs are potential futures: Can you not know... We note that the prophet appeals to the primary intuitions of mankind, or, at least, to a primitive revelation, rather than to the commandments of the Decalogue. (Psalms 19:4.)