LAUSR

We are living in a very strange time that has been dubbed a “post‐truth” world. For example, Chuck Todd, the host of the NBC TV programme Meet the Press, asked Kellyanne Conway, President Trump's counsellor, to clarify the comments by White House Press Secretary Sean Spicer about the size of the audience attending the Trump inauguration ceremony. They disputed the number of attendees as revealed by aerial photographs of the current and previous inaugurations. Eventually, Todd got the interpretation that Spicer had provided “alternative facts.” Such a concept is anathema for those of us with a scientific bent who accept that facts are things that are measurable, reproducible, and have been validated. This does not naïvely assume that facts have absolute values, as shown by the error bars that scientific papers routinely include as a way of quantifying uncertainty around the measurements. It does mean that facts are solid entities that can be used as a basis for rational discussion. For example, facts may be subjected to alternative interpretations about their significance for society without disputing their veracity. However, the more such interpretations deviate from the median, the greater the chance that the propounder belongs to the world of politics rather than the world of science. There is always the potential for the public record to be contaminated by statements purporting to be true, which are simple errors, inadvertent falsehoods, misconceptions, or downright lies. The underlying error may be the same in each case, but the description used will depend upon the intention of the original author; did they make an honest mistake, fall into an understandable misinterpretation, or deliberately set out to mislead? The Internet allows us to be directed to websites presenting the case for an amazing variety of subjects. The veracity of the information displayed on a particular unique resource locator (URL) does not correlate with the slickness of the presentation, so there are no apparent warnings that one may be about to enter a “post‐truth” area or one containing “alternative facts.” The algorithms that drive searches for information are based on the number of earlier searches for the same keywords that have linked to the same URL—a measure of popularity that cannot validate a particular website in terms of factual accuracy appropriate for identifying scientific facts. The same applies to the use of citations to particular articles in the primary scientific literature, as can be illustrated simply. Search for “side effects of MMR vaccine” and you will come across a 1998 publication in the renowned Lancet by Wakefield et al that will have been credited with many citations before it was formally retracted.