or Why I am not an Archaeologist. Cal Watkins presents the case for me:
The evidence that archaeology can provide is limited to material remains. But human culture is not confined to material artifacts. The reconstruction of vocabulary can offer a fuller, more interesting view of the culture of a prehistoric people than archaeology precisely because it includes nonmaterial culture. Consider the case of religion. To form an idea of the religion of a people, archaeologists proceed by inference, examining temples, sanctuaries, idols, votive objects, funerary offerings, and other material remains. But these may not be forthcoming; archaeology is, for example, of little or no utility in understanding the religion of the ancient Hebrews. Yet, for the Indo-European-speaking society, we can reconstruct with certainty the word for “god,” *deiw-os, and the two-word name of the chief deity of the pantheon, *dyeu-piter, Greek Zeus pater, and Luvian Tatis Tiwaz). The forms *dyeu- and *deiw-os are both derivatives of a root dyeu-, meaning “to shine,” which appears in the word for “day” in numerous languages (Latin dies; but English DAY is from a different root). The notion of deity was therefore linked to the notion of the bright sky. The second element of the name of the chief god, *dyeu-phter-, is the general Indo-European word for FATHER, used not in the sense of father as parent but with the meaning of the adult male who is head of the household, the sense of Latin pater familias. For the Indo-Europeans the society of the gods was conceived in the image of their own society as patriarchal. The reconstructed words *deiw-os and *dyeu-phter- alone tell us more about the conceptual world of the Indo-Europeans than a roomful of graven images.
That is from his excellent introduction to the American Heritage Dictionary's Appendix of Indo-European roots.