 Schopen is very critical of modern Buddhist studies because of its preference for literary evidence that "in most cases cannot actually be dated and that survives only in very recent manuscript traditions" that have been "heavily edited" and were intended as normative not historical accounts.Schopen believes that the preference for texts over archeology and epigraphy is a mistake and that it is Buddhist epigraphy which are the earliest written sources.Regarding the textual sources, Schopen holds that even the oldest sources such as the Pali canon, "cannot be taken back further than the last quarter of the first century B.C.E, the date of the Alu-vihāra redaction," but that actually it is not until the 5th or 6th centuries CE "that we can know anything definite about the actual contents of this canon."