Some argue that the Urim and Thummim in the Old Testament were simply a device used to get a "yes" or "no" answer. However, modern scholarship supports the view that they were more than that, and that the oracle using such received detailed revelation. The most scholarly work on the Urim and Tummim is that of Cornelis van Dam, The Urim and Thummim: A Means of Ancient Revelation in Ancient Israel (Eisenbrauns, 1997; reprinted in paperback in 2015). Jeff Lindsay has a very good summary of this volume on his Mormanity blog, Cornelis Van Dam on the Urim and Thummim
In the Eerdmans Dictionary of the Bible (2000), the entry on the Urim and Thummim, authored by Thomas B. Dozeman, summarises modern scholarship thusly:
URIM
(Heb. ʾûrîm)
AND THUMMIM
(tûmmîm)
Most likely divining stones used by priests to inquire judgments from God. They are first mentioned in Deut. 33:8 as belonging to the Levites in general, arising from their zealous devotion to God above family. As a consequence the Levites acquire three functions: they transmit divine law to Israel, burn incense, and sacrifice on the altar. The function of conveying divine judgments through teaching may be associated with the Urim and Thummim.
Priestly writers limit the use of the Urim and Thummim to the high priest. In Exod. 28:30 the Urim and Thummim are part of the special garments of the high priest, attached to the breastplate in a pouch. When the high priest wore the Urim and the Thummim in the inner sanctuary before God, he was not only representing the people before the deity, but actually seeking a divine judgment on their behalf. The details of the inquiry are not provided. If the Urim and Thummim were stones, then the ritual may have resembled the casting of lots, in which questions were posed to God requiring a “yes” or “no” answer.
The story of the choice of Joshua to succeed Moses in Num. 27:12-23 provides an illustration of how the Urim and Thummim functioned in relationship to the high priest. Here God informs Moses of his impending death and Moses requests a successor. God selects Joshua. But for this selection to be official, Joshua must be presented before Eleazar, the high priest, who must “inquire for him [Joshua] by the decision of the Urim before the Lord” (Num. 27:21). The brief statement by Saul in 1 Sam. 14:41 provides a glimpse into how the Urim and Thummim functioned as a casting of lots. In this story Saul requests Urim to designate guilt in himself and Jonathan and Thummim to designate guilt in the people of Israel. The Urim and Thummim are also mentioned in Ezra 2:63 = Neh. 7:65 without explanation or comment.
So, the Urim and Thummim did not produce only “yes” or “no” answers, but more detailed revelations, too. Such is consistent with the historical Latter-day Saint view of the nature of the Urim and Thummim which significantly predates modern scholarship that overturned the “yes” or “no” only thesis.
