344 Are the Androids Dreaming Yet? bad. If we measure something in the quantum world, it always yields a classical result — in this case the magnitudes of spin are 1, 0 and 1. (Minus one squared is one.) We need to imagine measuring the spin of a particle along three axes; x, y and z. Hold your hand up and make a shape that looks like the one in the following picture. You might remember it from science classes; it was used to help you understand Fleming’s left-hand rule. For our purposes it does not matter which hand you use; it is just the shape that matters. I am going to use my left hand for sentimental reasons. Now, imagine the palm of your hand is the measuring apparatus: your index finger the x axis, your middle finger, y and your thumb, z. At any moment you can move your hand to point in any direction and take a measurement. We will have to round up or down. Quantum mechanics is named ‘quantum because ail the readings must be whole numbers. You will never see 10% spin in x, 90% in y and 85% in z; just ones, and zeros. The measurements for a Boson will always be 1,0,1 in some order. This is known as the ‘101’ rule. Now, we ask the question: does a particle have a definite spin before we take a measurement? The instinctive answer is yes, and this way of viewing things is known as realism. It seems obvious that even if we did not make a measurement, the particle would still have its spin; we just wouldn't know which type. Einstein explained realism by saying “T like Kochen Specker HOUSE_OVERSIGHT_016034