 The other distinction falling into this third family is very similar to the DR/DN distinction. It also concerns the force, rather than the form, of a practical principle. The DR/DN distinction is in terms of which principles an agent must recognize as binding on her to avoid counting as irrational. A slightly different distinction is the between principles that really are binding on everyone (BN–“binding neutral”), even if one might not accept their authority without thereby counting as irrational, and those that are not (BR–“binding relative”). Drawing the distinction may commit us to the thesis that there is a fairly fundamental appearance/reality distinction to be drawn even with respect to principles of practical reason, so that even an ideally rational agent could, in principle, be mistaken at a given point in time about which principle(s) bind her without thereby counting as irrational. At any rate, it should be clear that this distinction, like the closely aligned DR/DN distinction is quite different from the AR/AN distinction.