Moshe achieved prophecy through philosophical thought

 Meshech Chochma (Devarim 34:8)…Moshe was constantly involved with philosophical thought concerning G d as can be seen from the book of Job which he wrote (Bava Basra 14b) which is totally philosophical. Shemos Rabbah (1:35) also notes that he tried to determine the reason for the exile in Egypt. Through his analysis he came to the true source and full knowledge to such a degree that he became a prophet.