If the locus classicus of eclecticism was Diogenes Laertius' Lives of the Eminent Philosophers, the locus modernus was the Introduction to Stoic Philosophy (1604) of Justus Lipsius (1547–1606), who argued that the method of critical choosing or "election" was superior to the dogmas of particular schools and represented the true road to truth. From the second quarter of the seventeenth century the term and concept of eclectic philosophy gained currency, as did the associated idea of the liberty of philosophizing (libertas philosophandi) —that is, the freedom to choose between philosophical schools, or indeed a philosophy beyond the schools. Gerardus Johannes Vossius (Gerrit Jansz Vos; 1577–1649) served philosophical apprenticeships in various schools—Aristotelians, Platonists, Stoics, and Epicureans—and concluded, "Clearly, I have become an eclectic." Later he defended eclecticism (secta electiva … sive electrix) as a permanent condition of philosophizing and urged, "How would it be in the future if we should be not Ionic philosophers, or Italians, Eleatics, Platonists, or Peripatetics, not Stoics, Epicureans, Skeptics, or any other such sects, but all of these?" (De philosophia et philosophorum sectis, 1658; Philosophy and the schools of philosophy).
The recognized founder of the eclectic school (eclectica philosophia; Wahl-Philosophie [Selective philosophy]) in Germany was Christian Thomasius (1655–1728), for whom, as for Vossius, philosophy was a collective enterprise not reducible to the teaching of one author or separable from learned tradition and succession of teachers. "I call eclectic philosophy," Thomasius wrote in his Introductio ad philosophiam aulicam (Einleitung zur Hof-Philosophie [Introduction to court philosophy]) in 1688, "not what depends on the teaching of an individual or on the acceptance of the words of a master, but whatever can be known from the teaching and writing of any person on the basis not of authority but of convincing arguments." For Thomasius the key to understanding was the alliance between history and philosophy. "History and philosophy are the two eyes of wisdom," he argued. "If one is missing, then one has only half vision" (einäugy).
Other adherents to eclecticism included J. C. Sturm, J. F. Buddeus, C. A. Heumann, Nicolas Gundling, J. G. Heineccius, Ephraim Gerhard, Arnold Wesenfeld, J. J. Brucker, and their students in many dissertations written in the late seventeenth and early eighteenth centuries in theology, mathematics, and medicine as well as philosophy. Eclecticism was a method of separating truth from opinion and falsehood, science from superstition, and so a process of intellectual enlightenment and human progress. As Heineccius concludes in his Elementa philosophiae rationalis et moralis (1756; Elements of rational and moral philosophy), "one should not seek truth by oneself, nor accept or reject everything written by ancients and moderns, and so no other method of philosophizing is more reasonable than the Eclectic Method."
Eclecticism was thus given new life in early modern times, appearing at the confluence of several intellectual movements: the revival of ancient and patristic learning, evangelical religious reform, the "liberty of philosophizing," and the adoption of critical history as the basis for understanding.
The most lasting consequence of eclectic philosophy was the emergence of a new discipline, the history of philosophy, beginning with Georg Horn and Thomas Stanley (History of Philosophy, 1655) and culminating in the first journal dedicated to the history of philosophy, the Acta Philosophorum by C. A. Heumann and the survey of J. J. Brucker (Historia critica philosophiae, 1742–1744; Critical history of philosophy), which set the canon for the modern history of philosophy and which was the basis for Diderot's entry in the French Encyclopédie.