 Brouwer [1908] observed that LEM was abstracted from finite situations, then extended without justification to statements about infinite collections. For example, let \(x, y\) range over the natural numbers \(0, 1, 2, \ldots\) and let \(B(y)\) abbreviate \((\primepred(y) \oldand \primepred(y+2)),\) where \(\primepred(y)\) expresses “\(y\) is a prime number.” Then \(\forall y (B(y) \vee \neg B(y))\) holds intuitionistically as well as classically, because in order to determine whether or not a natural number is prime we need only check whether or not it has a divisor strictly between itself and 1. 