That's the Heisenberg Uncertainty Principle. He's talking about the observer effect, which is a different thing entirely. If you want some background on it, goo

That's the Heisenberg Uncertainty Principle. He's talking about the observer effect, which is a different thing entirely. If you want some background on it, google the double slit experiment. This isn't an endorsement of Campbell's claims above, of course, just some clarity on what he's talking about.