  A different version of this picture maintains that invariant reasons derive from the virtues (Crisp 2000). That an action is generous, honest, just, thoughtful, or helpful is always a reason to do it. The invariant core is given by the virtues, therefore, and the variant periphery depends upon that invariant core. This last point is important, because this defence of generalism needs to show why it is that morality requires a basis of invariance. Just to come up with a few invariant reasons is nothing to the point. Those who suppose they can seriously damage particularism by specifying a few (probably fairly complex) invariant reasons do little to show that moral thought depends (as it was put in the Introduction above) on a suitable provision of principles (which we are now understanding as ‘invariant reasons’). The suggestion we are dealing with now does well in this respect. We are offered an invariant core and an account of why there must be such a core if moral thought is to be possible at all.