
Some Libertarians in the US and elsewhere certainly seem to think so, and refuse to wear them. But we are not Libertarians, and as Liberals it is easy enough for us to justify asking others to wear masks by drawing on two principles described by John Stuart Mill.
In On Liberty Mill explores his political philosophy and expounds on the Harm Principle:
That the only purpose for which power can be rightfully exercised over any member of a civilized community, against his will, is to prevent harm to others.
In other words, the potential for harm can outweigh the loss of liberty.
In Utilitarianism Mill develops this from an ethical point of view and outlines the Greatest Happiness Principle:
… actions are right in proportion as they tend to promote happiness, wrong as they tend to produce the reverse of happiness. By happiness is intended pleasure, and the absence of pain; by unhappiness, pain, and the privation of pleasure.
Whenever we, as a party, debate policy that might impact on our liberties, members tend to use one or other of these principles as justification for their position. For example, discussions some years ago about whether to ban smoking in public inside spaces often invoked the harm principle – smoking can cause physical damage to people nearby who are not smoking, including the people who work there. On the other hand, the powers adopted should be minimal, that is set at the lowest level to be effective, which is why we support outdoor smoker’s areas, where the harm is limited to the smokers themselves.