The prevailing modern publice thics adopts a lateral perspective based on the interpersonal mutual constraint.It aims at timeless principles,but virtually focuses on the temporal lateral relationship.This perspective fails to capture the diachronic lasting nature of political community,and prevents us from formulating a reasonable conception of social justice due to its presumptions about the agents as adults and normal persons,and its even-Steven moral attitude in the distribution of resources.A vertical dimension of time ought to be introduced which accounts for the socio-economic achievements in terms of social accumulation and develops an ethical justification for the fairdistribution of resources based on some kind of social asset irreducible to individual performances.But this vertical dimension of time neither implies an interpretation of public ethics in the light of inter-generational relationships,nor an attempt to resolve the conceptually questionable problem of inter-generational justice.Its essence lies in a trans-temporal or atemporal perspective in public ethics which is contrary to the timeless lateral thinking.