I think I understand this only up to a point. 1. Photon spin is quantized to be +1 or -1 and these represent left- and right-hand circular polarization. 2. A photon can have a superposition of 2 spin states in any proportion. 3. Having probability amplitude of 0.5 of spin 1 and 0.5 of spin -1 yields linear polarization, and the orientation depends on the phase angle between the two. 4. Here is my question: Suppose I let a photon with vertical linear polarization (obtained from a vertical linear polarizer) pass through another vertical linear polarizer. What is the transmission probability? Classical reasoning says 1.0. But if the photon can REALLY have only spin 1 or -1, the transmission probability is only 0.5 in either case and therefore 0.5 overall. I suspect the problem is with the word 'really' because we are not allowed to ask about objective reality. But please explain and, if possible, without ket signs or matrices.