In a 1942 paper, Dirac claimed that negative energy and negative this quantity are not nonsense and are mathematically well-defined like negative money. For a spin-0 particle, the current of this quantity is equal to (read slowly) h-bar over 2-m-i (15[1])times psi-star-del-psi (15[1])minus psi-del-psi-star. Application of the WKB (-5[1])approximation to a free particle (*) wavefunction gives a nonzero value to this quantity in classically (10[1]-5[1])forbidden regions. Born’s rule set the square norm of (10[2])the (10[1])wavefunction amplitude as this quantity. QBism is (10[2])an (10[1])interpretation of (10[1]-5[1])Quantum Mechanics (10[3])which uses (10[3]-5[1])a subjective Bayesian account of this quantity. (10[1])This quantity (10[1])over (10[1]-5[1])all space (10[1])for a normalized wavefunction is equal to (-5[1])one. For 10 points, identify (-5[1])this quantity that gives the (10[3])chance of observing a particle in (10[1])a (10[1])particular (10[1]0[2])state. ■END■