In an attempt to determine the solid surface tension components of the solid surfaces FC721, FEP, and PET, by using the Lifshitz-van der Waals/acid-base approach from the measurement of contact angles of different polar and apolar liquids, the solid surface tension components, gamma(s)LW, gamma(S)+ and gamma(S)-, were found to be inconsistent and strongly dependent on the liquids used. Accordingly, these solid surface tension components are not unique material properties of the solid surfaces and the acid-base approach is not applicable for the determination of solid surface tension components from contact angles. In addition, occurrence of negative values for the square root of gamma(S)+ and gamma(S)- suggests questionable physical meaning of the solid surface tension components, gamma(S)+ and gamma(S)-. It is also shown that the inconsistent and negative values of gamma(S)+ and gamma(S)+ are not a consequence of contact angle errors or errors in gamma(L)LW values.