The Best Way to "Prove" Something...

.. is to do your best to disprove it and fail. Or as the great men said:

• In relation to any experiment we may speak of this hypothesis as the “null hypothesis,” and it should be noted that the null hypothesis is never proved or established, but is possibly disproved, in the course of experimentation. Every experiment may be said to exist only in order to give the facts a chance of disproving the null hypothesis. - R.A.Fisher. The Design of Experiments, Edinburgh: Oliver and Boyd, 1935, p.18.
• In science, 'fact' can only mean 'confirmed to such a degree that it would be perverse to withhold provisional assent.' I suppose that apples might start to rise tomorrow, but the possibility does not merit equal time in physics classrooms. - Stephen Jay Gould
  

That's obvious to some and unsatisfying to others. According to this blogger we should not expect some people to search for the truth because their jobs involve advocacy. Scientists seem to take a harder line on this than business folks

• For a successful technology, reality must take precedence over public relations, for Nature cannot be fooled. - Richard P. Feynman