Divination (from the Latin: divinatio) is the act of discovering the hidden, but more particularly the future, in a supernatural way.
The Etruscans had a complicated polytheistic belief system which considered all visible phenomena of nature to be the manifestation of divine power and will. The gods were believed to influence the human world and to communicate through signs which could be interpreted in order to read the wishes of the gods, and to determine the most favorable course of action.
The Etruscans always consulted their gods before they would decide on any mater. They sought their gods' advice and wishes by studying the flights of birds, examining the markings on the liver of sacrificed animals, and watching the sky for the lightning, whose location and shape was believed to foretell the future or deliver answers to questions.
These signs from the gods were read by a class of professional priests who were well versed in the art of divination and the arcane meaning of symbols and omens. This "science" was later adopted by the Romans and incorporated into their own religious practices.
Some of the methods which the Etruscans used to predict the future or understand the wishes of the gods included:
The direction, pattern and even the timing of the flight of birds allowed Etruscan priests to decode the obscure wishes of the gods and the peer into the future.
The intestines and the liver of the sacrificial animals were examined for any imperfections or unusual markings or shapes. The Etruscan priests believed that the location of these "signs" on a liver corresponded in some mystical way to the dome of the heavens, and so they would first find a marking or blemish of interest and then, using a complicated system, transpose the markings onto a model of the visible heavens. Depending on which constellation or degree of the sky the marking fell would allow the priests to determine the future or other useful information about the gods' views on what was being asked.
Etruscan priests would watch the sky for lightning and carefully note its shape, color and position in the sky. The type of lightning and also where it appeared in the sky was believed to represent a clear message from the gods and the Etruscan priests would read these lightning signs and use them to predict the future.
Today it is nearly impossible for us to understand the level of confidence which the Etruscans placed on divination using these methods. In our modern society, we are used to even the best scientific prediction models not being completely accurate. For example, even with satellites and weather radar, we are not able to fully predict the path of a hurricane or whether it will rain tomorrow. Yet the Etruscans harbored no such doubts or reservations. They believed that the will of the gods was absolutely knowable through these methods of divination, and this there was no aspect of Etruscan life which was not determined by what the priests said these signs meant.
No business deal, no marriage, no war, was undertaken unless the entrails or the flight of birds said that it was good in the eyes of the gods.