According to John Stuart Mill, the biggest difference between modern life and the past is that, in the former, there is a much more individuality and lifestyle choices.

As a liberal, indeed as one of the greatest liberal thinkers of all time, Mill sees it as important for society to tolerate as many different lifestyles as possible and to avoid the crushing conformism that was the attitude of so many of his fellow countrymen in Victorian Britain.

In defending the different lifestyle choices that people make, Mill invokes the harm principle. The harm principle states that we should be free to pursue whatever actions we choose so long as they do not harm others. Harming others is not just wrong according to established convention, it also infringes on their liberty, and this is not conducive to a free society as Mill understands it.

That being the case, modern society should tolerate as many lifestyle choices as are compatible with the exercise of the freedom of others (causing them no harm).