In brief, one aspect of quantum mechanics is that certain observations cannot be predicted absolutely. Instead, there is a range of possible observations, each with a different probability. According to the MWI, each of these possible observations corresponds to a different universe, with some or many of the interpretation's proponents suggesting that these universes are as real as ours. Suppose a six-sided dice is thrown and that the result of the throw corresponds to observable quantum mechanics. All six possible ways the dice can fall correspond to six different universes. In the case of the Schrödinger's cat thought experiment, both outcomes would be "real" in at least one "world".