WE cannot unknow what we know. Worse still we cannot help but draw conclusions from what knowledge we have.

Those of us who have lived through the scandals of the East German medal machine in the 1970s and 80s; “the world’s dirtiest race” in the 80s; the ejection of Russians from the last Olympics because of “state-sponsored doping” find it hard not to be cynical in this post-Rumsfeldian world.

We cannot unknow that there remains an on-going investigation into the methods of Alberto Salazar, the man under whom Mo Farah has achieved most of his success, inviting speculation that the coach’s expected absence from London this week is because of the level of distraction both know it would generate. We cannot unknow that Farah offered a defence that many found implausible when claiming that the reason he had missed a dope test was that he had not heard his door bell being rung.

We cannot unknow that officials of the World Anti-Doping Agency reported that Jamaica, homeland of Usain Bolt, the greatest sprinter of all-time, failed to operate anti-doping procedures in the build-up to the London Olympics.

What we consequently think we know represents sufficient circumstantial evidence for many to be convinced that there remains cause for concern. Others, many of whom would prefer not to know what the rest of us know, are meanwhile incensed by the very notion that any doubt should be cast over the purity of the two great heroes of this generation of track athletes.

So, to what we know for certain.

We know Mo Farah – four-time Olympic, five-time World and five-time European gold medallist – is a man blessed with a formidable combination of East African genes and western world resources at a time when the acquisition of medals has become the most important sporting priority of the British political classes.

We know, too, that Usain Bolt – eight-time Olympic and 11-time World Championship gold medallist – is the first man of such height to find a way of getting his legs moving quickly enough to prevent his rivals from becoming uncatchable in the first 60 metres of 100m races.

Just as there is powerful circumstantial evidence to raise questions, so there is a compelling case to be made that these men, who have both repeatedly proclaimed their commitment to “clean” competition, are true champions in every sense.

History has told us that it is as foolish to cling dogmatically to either argument and the vast majority of sports lovers can merely hope that any suspicion is merely built upon ill-founded hypothesis at best and conspiracy theory at worst.

That it remains – and remains wholly plausible after such a lengthy opportunity to subject these men to the fullest possible scrutiny– is deeply sad, but we rely upon the notion of innocence until proven guilty.

For all that, we cannot unknow how little incentive there is in a brand-driven sporting world for the various authorities to assist in the process of investigating their superstars.