Morals are  just social standards, local social constructs.  Ethical philosophy aims to construct a model purporting to transcend such local artifice.  One possible source for such a model would be examination of the diverse social contracts in use.  The simplest way to use those sources to produce a transcendent model would be to look at what is universal, or at least strongly prevalent.  You would end up with something like the golden rule.  Nearly every standard says not to have double standards, but there are exceptions such as standards that propose different standards for different classes.  If the golden rule is a universal standard, then societies using such hierarchies of moralities violate the even higher morality of what most societies do.  This ignores the question of whether we are basing our privileging of the golden rule on how many distinct societies use or on how much population lives in those societies.  Are we voting by nation count or head count?  Are we including only the present, only the present and past or do we count the future as well?  

We can't actually assume the golden rule is a transcendent standard on the basis of its popularity because we can't even derive a way to determine popularity much less derive popularity itself.  What is clear is that the whole project of deriving a transcendent moral standard is to be able to judge not individuals but societies.  To say which kinds of moral standards vary from the norm in acceptable ways and which don't.  And the assumption of such an endeavor is that higher moral systems have authority over lower moral systems in some way.  Just as the rules for individuals in one caste differing from the rules for another caste presumes there is a higher rules system that assigns caste, similarly the kind of rules system established by any society can be judged with relation to a more global system for judging rules systems, and the feature of having a hierarchy of different moral systems within the society is one thing we know the metamorality will reject as a violation of metamorality.  But here's the thing.  Allowing any moral system to vary in any way is itself the establishment of a hierarchy of moralities.  It is assigning people a caste depending on what society they live in.  Such a metamoral system banning caste systems is itself a caste system and thus frowning on multistandard moral codes cannot be a feature of the metamoral system we are trying to generate.  Rather it must be a feature of the metamoral code that it judges a society good if it does recognize that different moral codes apply situationally.  The universal standard is that standards cannot be universal.  Therefore this one disproves itself also because it is itself a universal standard.

The only metamoral code that can be self consistent is one disallowing variant moral codes completely.  If there is a transcendent right and wrong it must disregard more local moral standards as having any place at all or else it must spell out organizing principles that insure there are never any conflicts (which makes them all part of one moral code that allows no variation).  A simple and arbitrary code, one admitting of no divergence is one such code. Such a code cannot be called a metamoral code, or transcendent code, because it doesn't in fact allow other codes, it's just a code that is in conflict with all other possible codes and thus it is inherently immoral.  The only complex or non arbitrary type of metamoral code that would qualify is a hierarchy of moral codes in which the top level moral code makes fewer and simpler demands and allows subordinate codes to add additional demands and complexity provided they don't contradict or subtract from more global standards.  In conclusion, a metamoral code must have a consistent organizing principle that incorporates variations between other moral codes into one larger moral code without conflict.  Such a metamoral code could be (but wouldn't necessarily be) self consistent because it could itself be a fully complying part of an even higher moral code. The devil is in the details, I suppose, but the takeaway is that a good metamoral code is capable of harmony with other codes (of whatever level) to the extent they are also capable of such harmony.  And that is the transcendent metametamoral code.  Prefer order over conflict.  

Theoconsequentialism is such an orderly code.  Its highest moral standard is compliance with the highest moral standards.  And it provides a way of ordering moral standards: popularity.  And it takes all times into account by positing that they are subsumed in the choices of the present population because they inspire it to exactly the right degree.  This assumption of perfectly adjusted amounts of inspiration is not empirically justified, but something like it is a necessary part of any complete metamoral system.  Alternatives include disregarding the past or present or future or any combination thereof, but they are equally arbitrary.  A metamoral code merely has to offer some solution to the question, it doesn't have to make any particular choice.   All that matters is how orderly and harmonious it is, and while alternatives may meet the minimum standard, theoconsequentialism offers the best possible way of optimizing order.  There is no better way of knowing the will of past and future people than to ask present people.  They can tell us what tradition says and they can project what the future may need.  How could we more privilege any other source?  Elite scholars?  Chosen how?  By other elite scholars?  Well that's less arbitrary.  Not.  

Being human gives a person a part of God's message to us.  We each have one letter on our shirt, and standing together we spell out the words of a message.  The letter on your shirt could even be a blank space between words, and you would count, for those are needed too.   Right and wrong is dictated by the totality of that message we spell out, not any one letter or word of it.  And it is constantly changing, as it should.  People come and go with different letters on them, so the message changes.  

No higher source of morality is possible.  If this is wrong, then it can logically be no more wrong than any other.