Rohan’s coffee with a friend was not a success. They had not seen each other for almost a year, but afterwards Rohan came home upset and angry. Their conversation had turned to the pandemic and to one issue in particular – vaccination. Rohan was fully vaccinated months ago while Sylvie has resisted, and in their discussion it became clear that they were at odds. Rohan argued that the vaccine offered a wonderfully effective way of reducing illness and worse. Sylvie suggested that vaccination is actually dangerous, possibly killing more people than it saved. 

Conflicts between friends can prove awkward but, as in this instance, their differences were soon put aside. However, what happened next was horrible and lasting. From an armchair at the far end of the room, Pierre, Sylvie’s husband, who had overheard the conversation, embarked on a loud anti-vaxx tirade directed against Rohan and her beliefs. She calmly countered his assertions but he spoke over her and, in a diatribe based largely on theories of conspiracy, he dismissed her claims one by one. A rational debate was out of the question. 

Hours later, Rohan, who was still seething, told me how she found it unbelievable that a teacher and scientist like Pierre could interpret the data in the way he did. How could he get things so wrong?

In response to her question I suggested that the difference in their two approaches might be explained by what I see as the ‘flagpole’ phenomenon whereby two sides can interpret apparently similar data differently. 

As a student, and later a young doctor, I was fascinated by how diagnoses were made. I watched as patients were admitted to hospital as ‘blank sheets’ and, in next to no time, had a defined condition on which to base their treatment. Those in charge – by tradition a team headed by a consultant whose say was final – used a standardised approach to make a decision based ultimately on how they interpreted the patient’s story and then integrated this with what they found on examination and later with the results of tests.

Hundreds, if not thousands of facts are sieved and a first step is to decide which findings most strongly point to a diagnosis. So, for example, when one patient described her illness, amongst other things she mentioned feeling sick and having tingling fingers but to the doctors the more pertinent part of her story, to which they give higher priority, was her shortness of breath and severe chest pain. With these two cardinal features a provisional diagnosis of heart attack (myocardial infarction) was flagged up. Once this particular flagpole was raised the team tried to confirm its position by asking her more questions, by re-examining her and by undertaking more tests. If everything remained consistent when integrated around the flagpole, then the original diagnosis would stand. If, however there were findings that didn’t fit, the working hypothesis would have to be modified or even abandoned. 

In all this, using the same process, a second clinical team with different insights and experiences might initially flag up an altogether different illness; for them the chest pain and shortness of breath might have been caused by a blood clot lodging in the lungs. For a third team the same features might have lead to a psychiatric condition. 

In each instance the teams saw the ‘facts’ from their own perspective and integrated them accordingly. Usually, however, differences in the diagnosis would be resolved with sophisticated and targeted tests which in my early medical days were difficult to come by. Creating a flagpole round which theories are declared and differences explored is the bread and butter of medicine.

In many ways, these principles, whereby individuals or groups select information in order to make a diagnosis, also operate in science and politics. Interestingly, in these instances, the flagpole may also become a bastion for adherents as zealots compete with opponents and detractors of other theories. 

Critically, scientific and political paradigms attract further research and analysis with those results that fit being integrated into the notional flagpole. Importantly, whatever its strengths, the paradigm will one day ‘fall’ when new information does not fit so making the original theory no longer tenable. Newton’s classical theory of gravity was, after all, superseded by Einstein’s position. 

One problem when creating a flagpole is that some people rely on evidence that is unreliable, even bogus. Moreover, some theory creators, such as those behind the anti-vaxx campaign, are not concerned about the validity of their sources; all that is sought is ‘evidence’ that strengthens their position.

The way in which medical, scientific or even political theories are developed through varying interpretations of data, inevitably leads to differences of opinion. Such differences, which should be recognised, are best resolved amicably, but this can be difficult if adherents are keen to proselytise. 

The illustration shows a picture of a rioter in France claiming, or so it would seem, that vaccines against the Coronavirus don’t work and give only a false sense of security.

For helping me write this blog I would like to thank Paul, Rohan and Vivien.