How is present knowledge wholly dependent upon past knowledge?
Because the knowledge is in God, the Eternal. We achieve knowledge according to His will:
Quran 2:255:
God: there is no deity save Him, the Living, the Eternal
One. Neither slumber nor sleep overtakes Him. To Him belong whatsoever
is in the heavens and whatsoever is on the earth. Who can intercede
with Him except by His permission? He knows all that is before them
and all that is behind them. They can grasp only that part of His
knowledge which He wills. His throne extends over the heavens and the
earth; and their upholding does not weary Him. He is the Sublime, the
Almighty One!
And He wills:
Quran 96:1-5
Read: In the Name of your Lord who created. (1) Created man from a
clot. (2) Read: And your Lord is the Most Generous. (3) He who taught
by the pen. (4) Taught man what he never knew. (5)
Knowledge of menkind is growing through God:
Quran 2:31
And He taught Adam the names - all of them.
Quran 3:48
And He will teach him writing and wisdom and the Torah and the Gospel.
Quran 3:3-4
He sent down to you the Book with the Truth, confirming what came before it; and He sent down the Torah and the Gospel. (3) Aforetime, as guidance for mankind; and He sent down the Criterion.
A growth of knowledge is there. But the main Islamic philosophy (also Christian philosophy) is that past and present and future are present in God.