Sayeth Senator Rand Paul, defending a supposed liberty interest of anti-vaxxers to choose to risk public health with diseases carried by their children. The idea may appear to embody a certain common sense, that government shouldn't take control of something previously left alone by government. As typically expressed by American conservatives in general, Repubicans in particular and especially by Libertarians like Senator Paul, it means that government shouldn't ever regulate anything.
The past, of course, is the best teacher about how people ought to shape their societies going forward, but mostly about how not to do things and what doesn't work very well, in terms of General Welfare. To illustrate that more clearly, take the remark by Senator Paul, made the title of this post. Senator Paul's comment makes the point that mandatory child vaccination regulations are a relatively modern innovation, since the first discovery of vaccines. However true, such a point means nothing if conditions existing in history have now changed.
But, for most of the history of vaccines, medical science was otherwise nowhere near as complex or advanced, as today. Once, hardly any significantly immune-compromised people would be encountered in public institutions and places; they typically died quickly (i.e. GOP healthcare plan). Today, such patients are among us everywhere, always. Because many of them cannot be immunized, the rest of us become obliged to avoid carrying disease in public, where vaccines permit us to do so. In this case history teaches us that things have changed, so something different is called for than before. Traditional values, family values, strict construction and other code words and phrases make appeals to history as empty and harmful as Senator Paul's simpleminded argument. No one has the liberty to harm their neighbor and that is exactly what the anti-vaxxers and their enablers are demanding.