The presumption of innocence, sometimes referred to by the Latin expression ei incumbit probatio qui dicit, non qui negat (the burden of proof is on the one who declares, not on one who denies), is the principle that one is considered innocent unless proven guilty.
In many states, presumption of innocence is a legal right of the accused in a criminal trial, and it is an international human right under the UN's Universal Declaration of Human Rights, Article 11. Under the presumption of innocence, the legal burden of proof is thus on the prosecution, which must collect and present compelling evidence to the trier of fact. The trier of fact (a judge or a jury) is thus restrained and ordered by law to consider only actual evidence and testimony presented in court. The prosecution must, in most cases prove that the accused is guilty beyond reasonable doubt. If reasonable doubt remains, the accused must be acquitted.
Under the Justinian Codes and English common law, the accused is presumed innocent in criminal proceedings, and in civil proceedings (like breach of contract) both sides must issue proof.
Some points to consider next time people are screaming for sackings, criminal charges or jail time.... Whether the clinic big hitters choose to acknowledge it or not the burden of proof is on the accuser and the presumption of innocence stands until proven guilty...as some of us have been saying.
Internet speculation and gossip is fine, a suspicion based on historical knowledge of the sport is fine too but when talking about legal ramifications and purple losing jobs, being banned from the sport etc things get serious and you then have to come up with better than 'the sport is dirty so Wiggins and Froome must be to too'...that just doesn't stand up to scrutiny, witness testimony is better, failed tests even more so...that's what most people would consider proof.
If you don't have faith in Wada or the testing system put your energies into changing that, it would be more productive than throwing around videos of riders looking good and making snidey comments about motors or doping when there isn't any proof yet.
Lastly, nobody in their right mind thinks the sport is clean...you only have to watch the recent 100m final to see that an unrepentant twice banned doper can win a race at 35 yrs old to see that the testing is far from perfect...but the cloud over Gatlin shouldn't detract from audiences enjoying the performances of athletes that haven't failed tests and are thus seen as clean, that's where I stand on the matter, as a fan of sport in general I love seeing the extreme end of human performance, if it turns out to be dirty then I'll happily see the offending athlete serve a life ban but if the athlete never fails a test, no journalists ever uncover incriminating stories about them and no witnesses come forward then they're either clean or have beaten the system and the overly skeptical voices of a few internet experts doesn't provide the proof needed to tarnish their efforts.
I'm happy to entertain the more fanciful claims in this forum but I'll also never tire of trotting out the above quote when posters are screaming for heads next time their favourite cycling villain has a good ride, there are always at least two sides to any argument and it's good to have a lively debate about doping, what constitutes evidence as opposed to proof etc and what the legal thresholds are when talking about depriving people of their livelihoods and/or liberty having committed (or been suspected of committing) doping offences.