We experience the world as a series of observations. Predicting those seems to be fundamentally impossible.
Of course that still leaves room for an omniscient being that never collapses the wave function and just deals in probabilities. But then your predicitions sound like "there's a 99.978% probability you will be hit by a car on tuesday at 10:04 am." with the remaining 0.022% accounting for quantum flactuations adding up to produce a different result. Whether you call that "all knowing" and whether that proves that nothing is random sounds like an interesting philosophical question.
Of course that still leaves room for an omniscient being that never collapses the wave function and just deals in probabilities. But then your predicitions sound like "there's a 99.978% probability you will be hit by a car on tuesday at 10:04 am." with the remaining 0.022% accounting for quantum flactuations adding up to produce a different result. Whether you call that "all knowing" and whether that proves that nothing is random sounds like an interesting philosophical question.