And likewise, the same holds the more we know about our velocity change in velocity. The less our change in velocity is. And the less we know about our change in x, the less we know about our position. In other words, we can't be very certain about our position and at the same time about our velocity. That's what the uncertainty principle tells us. And this has to do with the duality nature of subatomic particles, electrons and protons, as well as a duality of light.