Logical purity
We are left to empirical observation to determine whether there are as many as n individuals in the world. Among “possible” worlds, in the Leibnizian sense, there will be worlds having one, two, three, … individuals. There does not even seem any logical necessity why there should be even one individual1—why, in fact, there should be any world at all.
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1 The primitive propositions in Principia Mathematica are such as to allow the inference that at least one individual exists. But I now view this as a defect in logical purity.