I develop an argument for the Causal Principle: If x begins uncaused, y would also begin uncaused, which is not the case; therefore, the antecedent is not the case, and reply to objections by Oppy, Almeida, Linford, and others. I refute the claim that x (the initial state of reality: ISOR) begins uncaused as brute fact, and I refute the claim that pre-existing abstract objects provide the required metaphysical grounding. I demonstrate that there isn’t any concrete object that can provide the required grounding because (i) there would not be any causally antecedent condition which would make it the case that x rather than y (e.g. electric fields increasing in strength; energy-conserving changes) begins uncaused, (ii) the properties of x and the properties of y which differentiate between them would be had by them only when they had already begun to exist, and (iii) the circumstance is compatible with the beginning of y. I also defended an alternative Modus Tollens argument which shows that if x (e.g. our spacetime block) begins uncaused, then some other possible spacetime blocks (e.g. y) would also begin uncaused initially and collide with ours, causing massive disruption, which is not the case; therefore, the antecedent is not the case.