(i) God is omniscient; therefore, for any change, C, among particulars, God knows the occurrence of C. (ii) If God knows the occurrence of C, then X. (iii) not-X. It is clear that the set of propositions (i)—(iii) is inconsistent. This is the general form of two problems—which I call the ‘problem of change in knowledge’ (PCK) and the ‘problem of change in essence’ (PCE)—for Avicenna concerning God’s knowledge of particulars. No work in the secondary literature has discussed exactly what PCK and PCE are. In this paper, I will clarify exactly what they are.