Another challenge for temporal neutrality may be posed by those who deny the commonsense view there is an enduring self or ego that persists through time while being wholly present at each moment. For the alternative is to see personal identity as a mere construction of sorts, perhaps consisting in nothing more than the right sorts of physical and psychological connections between various temporal parts, or momentary time-slices of a person. In that case, it may seem that what I am, at the most fundamental level, is not a whole temporally-extended person at all, but just a momentary time-slice. The relation my momentary self bears to my future selves then rather resembles the relation my person bears to other - more or less similar - persons. However, most of us think that it may be quite rational to be personally biased, in the sense of favouring some persons (e.g. ourselves and those close to us) over others. So why is it not likewise rationally permissible to favour some momentary time-slices (e.g. our present moment, and those close to us-now) over others?
I grant the underlying metaphysical picture, and will remain neutral on whether full-blown personal neutrality is rationally required. So I agree that if one were to psychologically self-identify with one’s momentary time-slice only, then bias against later time-slices could reasonably follow. For in such a case, one would arguably no longer be a person with a future at all. This is implied by the following endorsement condition (EC) on the construction of personal identity:
(EC) Any temporal proper part of a person must (at least implicitly) endorse its incorporation into the temporally-extended whole.
The sort of implicit endorsement I have in mind is satisfied by conceiving of oneself as a temporally-extended person, for example identifying with the subject of one’s memories, anticipating future experiences, etc. We may imagine someone - call her Mini - who, upon rejecting endurantism about the self, goes on to purge herself of all such thoughts. By failing to imaginatively project herself beyond the confines of her present moment or otherwise consent to incorporation into a temporally extended whole, Mini’s person would extend no further than the time-slice. The subsequent time-slices will of course bear various relations to her, being continuous in many notable respects, but they no more comprise a unified person than do people with similar interests automatically comprise a club. Persons, on this view, are voluntary associations.
Mini is not biased against her future, then, because she has no future. We do better to describe the situation as one in which she is biased against the people who later inhabit her body. If we reject the strict requirements of personal neutrality, then we may consider Mini to be reasonable in her bias. But it is not fundamentally temporal bias. It is just an unusual case of personal bias.