PESCH, TILLMANN. - Jesuit, brother of the preceding, philosopher, born in Cologne on 10 February 1836, died at Valkenburg on 18 October 1899.
Having entered the Society of Jesus in 1852 and been ordained a priest in 1866, he taught philosophy to his confreres at Maria Laach (1867–69). From the outset, he distinguished himself by his love and esteem for Aristotelian-Scholastic philosophy, which at that time was considered outdated both in content and method; he conceived of a restoration of Christian philosophy in Germany through an effective defense and exposition of medieval philosophy, enriched and adapted to the achievements of modern science. Indeed, he played a major role in the renewal, initiated by Fr. Kleutgen (q.v.), of Catholic philosophy, contributing even before the encyclical *Aeterni Patris* (q.v.) to the return to the fundamental theories of Scholasticism, in accordance with the will of Leo XIII. After a brief interval devoted to priestly ministry (1870–1872), he went to Tervueren (Belgium) to work on the periodical *Stimmen aus Maria Laach* and began publishing the supplementary series *Ergänzungshefte*. From 1876 to 1884, while continuing his work as a writer, he again taught philosophy at Blüenberg, Exaeten, and Valkenburg.
In addition to numerous articles in *Stimmen* defending medieval philosophy, he composed for the *Ergänzungshefte* series, against Kantian theories: *Die moderne Wissenschaft betrachtet in ihrer Grundfeste* (Freiburg im Br. 1876); *Haltlosigkeit der modernen Wissenschaft, eine Kritik der Kant'schen Vermunftkritik* (ibid. 1879); *Das Weltphänomen. Eine erkenntnistheoretische Studie* (ibid. 1881). Meanwhile, he developed the plan for a complete course in philosophy, under the title *Philosophia lacensis*, beginning the series with *Institutiones philosophiae naturalis* (*Cosmogonia* [2 vols., ibid. 1880; 2nd ed., ibid. 1887]), which earned him membership in the Academy of St. Thomas in Bologna. This was followed by: *Institutiones logicae* (3 vols., ibid. 1888–90; new ed. edited by Fr. C. Frick, *Institutiones logicae et ontologiae*, 2 vols., ibid. 1914–19); *Institutiones psychologiae* (3 vols., ibid. 1886–98). Another notable publication is *Die grossen Welträtsel. Philosophie der Natur allen Naturfreunden dargeboten* (2 vols., ibid. 1883–84; 3rd ed., ibid. 1907), in which he refutes, with the aid of all the sciences, the manifold aberrations then prevalent of materialism, atheism, and monism. Against Lutheranism, on the occasion of the centennial celebrations of Luther in 1883, he published a concise apologetic work under the pseudonym “Gottlieb”: *Briefe aus Hamburg* (2 vols., ibid. 1883–89; 5th ed., ibid. 1905), a defense of the Church against the assertions of seven notable adversaries of the divinity of Christ; this later formed Vol. I of the work *Christ oder Antichrist*, to which he added as Vol. II *Der Krach von Wittenberg* (ibid. 1890; 2nd ed. 1894). In the ascetical field, he wrote *Das religiöse Leben* (ibid. 1878; 23rd ed., ibid. 1922), a small book of prayers and advice for educated men, and *Christliche Lebensphilosophie* (ibid. 1895; 22nd ed. 1923). He also founded the apologetic collection *Flugschriften zur Lehr und Wehr*, which was distributed in more than a million copies.