Free Will 335 We could liken photons knowing three pieces of information to children in a playground choosing to wear either hats, scarfs or gloves in some combination: hats for vertical, gloves for 120 degrees and scarfs for 240 degrees. There are eight choices for each child; nothing, hat, gloves, scarf, hat and scarf, hat and gloves, scarf and gloves, or all three. Bell asked how often we would see two measurements agree. Look at the illustration and you can see when this happens. If a child was wearing all the clothes then if you check any pair, say gloves and scarfs you will always get a yes. If one of the children is wearing none of their winter clothes, you will always get a no for any pair you check. In these two cases, we are always sure to get agreement. For all the other cases, only one in three of the tests will agree. So Bell said that any time you have something with three hidden variables, there is at least a one in three chance that the measurements you make will agree, since six of the tests are one in three and the other two are certain. Due to Heisenberg’s Uncertainty Principle we can only look at one piece of clothing at a time. But, there is a trick. If there are identical twins among the children — who always dress the same way in our analogy - we can look at the gloves of one twin and the hat of another. Because they are twins if the first twin is wearing a hat we know the second one is too, without looking. We have a trick to measure two things at once. When the test is done on twin photons only one in four, one quarter, agree. So there is a problem with the children analogy. It turns out photons don't wear gloves, hats, and scarfs. There are no hidden variables. A photon does not know what it will do before you measure it and can only decide on the fly at the point of measurement. This means quantum particles are not there when they are not being observed. Observing them does appear to make them real. If the hidden variables, the gloves