Alethiology (or Alethology) literally means 'the study of truth', but can more accurately be translated as 'the study of the nature of truth'. It could be argued that this is synonymous with epistemology, the study of knowledge, and that dividing the two is mere semantics, but there is a defintite distinction between the two. Epistemology is the study of absolute or factual truth - or to coin a phrase of 'known knowns'. Alethiology is more deeply concerned with the nature of truth rather than the facts of truth. What is truth, rather than what facts are true.
Of course, this argument is fascinating to me, as up until now I've debated with people from the secular end of the spectrum who claim that Childs is too Christian and thus imports an external ideology into ancient texts.
Seitz has commented on the wide spectrum of disagreement on Childs' approach: from both the left and the right. To quote:
Childs's Biblical Theology may prove to be a book in search of an audience, and for that reason it will be judged by the widest variety of readers as learned but unsatisfactory and by an even smaller audience as the most brilliant proposal for theological exegesis offered in recent memory, but one unlikely to gain the sort of foothold necessary to transform the church in its use of scripture. (1998: 108, 9)