Reasons, identity, and future people › Concern for ourselves and others

The third part asks how a reductionist understanding should affect prudence and morality. If a separately existing ego is not what unifies a life, one proposed justification for an absolute boundary around self-interest loses support. That leaves room to reconsider the weight of psychological relationships and the significance of distinctions within and between lives.

This is a challenge to a justification of exclusive self-concern, rather than a proof that all special concern is irrational. Projects, attachments and commitments can supply reasons that do not depend on a further metaphysical fact. A person can continue to plan for old age while rejecting the claim that a simple persisting substance explains why those plans matter.

Parfit also describes changes in his own attitude toward death associated with reductionism. That is a philosophical and personal reflection, not evidence that adopting the view reliably reduces fear. A reader may find the view consoling, unsettling or unpersuasive. None of those reactions alone determines whether the account is true.

The distinction protects the inquiry from becoming advice it cannot support. An abstract identity argument does not tell someone to abandon relationships or disregard their future welfare. Its value is in making the grounds of concern available for examination. The ethical conclusions need the same care as the metaphysical claims on which they draw.