What? Since when is science a court of law? New scientific hypotheses aren't assumed to be false before they're proven true, the assumption depends on the experiment and background knowledge (and perhaps the gumption of the experimenter). New scientific theories aren't assumed false before they're proven true, nor are scientific laws assumed to be false before you can point to something and say, 'aha! it is true after all!' To become a theory or law in the first place requires many observations or calculations of an aspect of our universe, and then also ensuring that these results don't come about by some other means.
But all of this is subject to new ideas and new interpretations. It used to be thought true that the atom was the smallest particle in the universe. It used to be thought true that the sun orbited the Earth. It used to be thought true that the species of the Earth were placed here fully formed and evolved to their final states. All of this has been since proven otherwise by later information, but for a time these were scientific truths.
And finally, have you observed the Big Bang? Have you really been unable to know both the speed and position of an electron or are you just not trying hard enough? Observation has never been an absolute necessity for science, calculation and proving the negative are just as much a part of the scientific method as physical observation.