In many physics divulgation books I've read, this seems to be a commonly accepted point of view (I'm making this quote up, as I don't remember the exact words, but this should give you an idea): > [Heisenberg's uncertainty principle](http://en.wikipedia.org/wiki/Uncertainty_principle) is not a result of our lack of proper measurement tools. The fact that we can't precisely know both the position and momentum of an elementary particle is, indeed, a property of the particle itself. It is an intrinsic property of the Universe we live in. Then this video came out: [Heisenberg's Microscope - Sixty Symbols][1] (skip to [2:38][2], if you're already familiar with the uncertainty principle). So, correct me if I'm wrong, what we may claim according to the video is: > the only way to measure an elementary particle is to make it interact with another elementary particle: it is therefore **incorrect** to say that an elementary particle **doesn't have** a well defined momentum/position before we make our measurement. We cannot access this data (momentum/position) without changing it, therefore it is **correct** to say that our ignorance about this data is not an intrinsic property of the Universe (but, rather, an important limit of how we can measure it). Please tell me **how** can both of the highlighted paragraphs be true or how they should be corrected. [1]: https://www.youtube.com/watch?v=dgoA_jmGIcA [2]: http://youtu.be/dgoA_jmGIcA?t=2m38s