quantum mechanics says that one cannot say for sure both the location and velocity of a given sub-atomic particle. the only reason we can do such on macro-matter is because we can identify the forces acting upon matter (gravity and the electromagnetic force). Therefore, there are other forces, other than, or including the strong force and the weak force that act upon sub-atomic particles that can be identified and quantified (pardon the pun) that can provide accurate predictions as to the location and velocity of such sub-atomic particles.