The cat paradox a little about paradoxes more about Schrodinger's cat what is probability? concrete objects classes of concrete objects abstract objects the key principle Einstein-Podolsky-Rosen's (EPR's) paradox angular momentum and spin Bohm's paradox polarization of photons aspect's experiment a short stop for reflections properties of concrete human beings mutual understanding an individual and society social sciences, utopias and doctrines how reliable is a poll? probabilities revisited states and beyond what is quantum physics? the Schrodinger equation - its origin and meaning what is a particle? Is it a corpuscle, a wave, or both? the double-slit Gedankenexperiment - what does it prove? Wheeler's delayed choice experiment a brief discussion of the Heisenberg's uncertainty principle is the world real? the mystery of the photon.