Joe: Liberals argue that…
Joe: Liberals argue that private charities will not be sufficient. That’s an empirical question, and it’s one that would be hard to answer short of actually trying it.
These premises aren’t sufficient to make the liberal case for the welfare state against libertarian objections, unless you add the further premise (or a more rigorous formulation thereof):
If voluntary charity isn’t sufficient to provide for autonomy, then people can legitimately be coerced into making up the difference.
But that’s not an empirical claim, and it doesn’t just fall out of a “respect for autonomy,” either: after all, it involves sacrificing at least one person’s autonomy, putatively to bolster another person’s autonomy; and it involves sacrificing one form of autonomy, putatively to bolster another form. Libertarians could very well regard charity as a duty, and could hold, empirically, that voluntary charity won’t in fact be “sufficient” (by whatever standards) for everyone to count as having lived up to that duty. The only thing they would need to maintain, to remain consistently libertarian, is that you also have a duty not to coerce anybody to make it “sufficient.”