prerogatives.6 When this happens, man no longer masters nature in order better to realize the truth of his own person, but his domination becomes an end in itself, the unifying principle of all natural and social relations. To speak the language of a more recent philosophy, we could say that what then prevails and imposes itself is “instrumental reason.” Along the same line as that indicated by De Trinitate, St. Thomas Aquinas stresses further the possibility of conciliation, in a hierarchical and