Zimmer (1990a) points out that the inference that the horse was known to the Indo-Europeans is primarily based on such poetic formulas as 'swift hors… - Stefan Zimmer

It is therefore historically irresponsible for the linguist to speak of 'Proto-Indo-European' in the 4th millen- nium, and linguistically meaningless for the archaeologist to argue about 'Proto-Indo-Europeans' living somewhere before ca 2500 B.C.

It must be stressed, and cannot be said often enough, that whatever date is given for 'PIE,' it is necessarily no more than pure speculation.

Every attempt, then, to give absolute dates for 'Proto-Indo-European' (or dates for alleged different stages of'PIE') is either based on the speculative identification of an archaeological culture with the speakers of the 'language of the PIE's' (e.g. Gimbutas, Renfrew, Mallory) or on what may be called 'intelligent guesses,' deliberations of probability and feelings of appropriateness (e.g. Meid, Gamkrelidze-Ivanov)" (372). ... "The first type of proposal is usually contested by fellow archaeologists and doubted by linguists, the second, being purely subjective because objective arguments simply do not exist, is bound to remain noncommittal. As is easily to be seen, many dates of both types have found their way to an often far too skeptical public.