The argument from antiquity (argumentum ad antiquitatem)...you've all probably heard it or been on the receiving end of it in religious discussions - the church has always believed this/done it this way, therefore it is right and true! A commenter on my recent post on relics suggested that because the church had always venerated relics, the practice was legitimate, and it was up to objectors - like me! - to prove otherwise. However, we don't need to go down the evidentiary path to dispose of the argument for relics from the supposed antiquity of their veneration. The argument from antiquity has a superficial appeal, particularly because most Christians have an innate respect for tradition; indeed, even Lutheranism is known as 'the conservative Reformation' because it kept so much of the liturgical and theological tradition of Western medieval Christianity intact (how the Lutheran confessors measured and sifted tradition is a subject for another post). But in actuality the appeal to antiquity is an informal logical fallacy which proves nothing and should not be used in argumentation.
There are two difficulties with it as it relates to the question of relics: 1) the empirical difficulty of proving the antiquity and universality of the veneration of relics (the New Testament, which all parties to the discussion agree is authoritative, does not mention the practice, so we may reasonably assume that at some point it was an innovation, just as was the veneration of images - this is actually where the burden of proof enters in to this discussion); and 2) the logical difficulty that the antiquity of a practice simply does not prove its truth or goodness (otherwise we might all still happily be sacrificing our children to Molech!). Even the church fathers themselves knew to avoid this fallacy; as Cyprian once wrote, "custom without truth is simply the antiquity of error".
Without institution by the Lord, or apostolic authorisation (and it is really differences in how dominical and apostolic authority are conceived which are behind this discussion), churches which use relics as 'sacramentals' and display them or carry them about for the purpose of veneration, or who claim to heal and bless by them are simply arrogating to themselves an authority which belongs to God alone. God has given the church the means of proclaiming and distributing his grace - his Word, the rite of Baptism and the Lord's Supper, all clearly attested to in scripture. Are they incapable of effecting grace and salvation, that the church should feel the need to invent more?