The article analyses whether it is correct to extrapolate the concept of "meaning in life" developed by Thaddeus Metz to the doctrines of ancient philosophers, including Thomas Aquinas. Is Metz’ concept of "purposes" that make "human life" meaningful analogous to Aquinas’ concept of "ultimate goal of man"? Significant points of Metz’ conception of "meaning in life" in our article are described and compared with Aquinas’ conception of "ultimate goal of man." As it turns out, these conceptions are only superficially similar. (...) In fact, they are profoundly different: (1) Aquinas is talking about the "goal of man", which implies objective teleology incompatible with Metz’ "naturalism", and is not talking about "meaning in life" (and even "purpose of life"); (2) "ultimate goal of man", for Aquinas, is intended to provide salvation and eternal life for man, not to make life "significant" in this world. -/- Thus, Metz and Thomas not only use different terminology, but also address different problems. They deal with different questions, not just give different answers to the same question (about the "meaning in life"). Metz’s extrapolation may be correct, when viewed as a kind of rational reconstruction. However, Metz does not make appropriate reservations and groundlessly unifies heterogeneous problems. The article shows that more historically oriented methodology avoids impropriety in the exercise of rational reconstruction of "meaning in life" in the field of ancient and medieval philosophies. (shrink)