Along with Gerard Philips, Charles Moeller and many others from other disciplines (Delhaye, R. Aubert, Coppens, Onclin...), Gustave Thils (1909-2000) is basically the fruit of Cardinal Mercier's concern for the intellectual and spiritual preparation of the diocesan clergy of Brussels (Mechelen) and for the intellectual and Christian revival of the University of Louvain.

Thils was trained in the diocese of Brussels, in its minor and major seminaries; and in Louvain, where he did his Degrees and his thesis , doctoral (1935) and habilitation (1937), on The Notes of the Church in Apologetics since the Reformation, showing the changes they had undergone as they moved from patristics and the Creed (one, holy, catholic and apostolic) to the confessional controversy with Lutheranism. It was one of the classic themes of the subject apologetics. And this subject was the first one he taught when he was asked to be a professor at seminar (1937-1949). He was also one of the most appreciated spiritual directors of that seminar, then with more than two hundred candidates. He then became professor of Fundamental Theology in Louvain (1947-1976). 

Thils was characterized by being thoroughly informed on the subjects he had to teach or wanted to introduce. He was not satisfied with the usual manuals. In each case, he composed a history and a thematic overview. And since, especially in the seminar, he was involved in several subjects, he soon produced a set of very informative works. This earned him an early reputation and was quoted throughout the theological area of the French language . Until almost the end of his long life, he maintained his ability to write clearly and synthesize well. And he was widely translated. 

The spirituality talks of seminar became a synthesis of priestly spirituality, The Diocesan Priesthood ( 1942-1946), later expanded in Christian Holiness. Compendium of Ascetical Theology and, later, in Existence and Holiness in Jesus Christ (1982). They continue to be inspirational and with a lay spirituality. 

Some courses on virtue morality at seminar gave rise to the interesting essay Current Trends in Moral Theology (1940). The thematic expansions of Apologetics and Fundamental Theology (and of his thesis ) led him to synthesize a celebrated History of the Ecumenical Movement (1955). And, bringing it all together, to a Current Orientations of Theology (1958). It also led him to study historically the role of the primacy in the Church, in La infalibilidad pontificia ( 1969) and El primado pontificio ( 1972). And, always in the line of Fundamental Theology, to introduce himself into the world of religions, Purposes and Problems of the Theology of Non-Christian Religions (1966). And, seeing them coming, Syncretism or Catholicity? ( 1967). And this is only a small selection of his books, to which must be added many articles and a great many reviews and reviews. He wasted no time. 

But his most recognised contribution was his early Theology of Terrestrial Realities(Théologie des réalités terrestres ( Desclée 1946, edition for which we will quote). This was later accompanied by other complementary essays, such as Transcendence and Incarnation (1950), and Theology and Social Reality (1963). 

He was original because he approached topic systematically, and with sensitivity to the way of thinking of professionals and workers, whom he knew because he led groups and gave courses. 

When it came to the Council (1962-1965) and especially in the work on Gaudium et spes, he was counted on. Apart from the fact that he was a companion of other Lovanians such as Gerard Philip and Charles Moeller, who had a great influence on the final form and the essay of Lumen Gentium and other documents (they were all good Latinists). He gave good commentaries on the progress of the Council and several of its documents. And he worked in the Secretariat for Christian Union. 

The medieval world has disappeared. Christianity (the Church) is no longer given an official place in the constitution of states. But how can Christians be disinterested in the temporal city, do they not have their mission statement and vocation there, especially the laity? What is to be done, without falling into clericalism? 

"Give to God what is God's and to Caesar what is Caesar's". From agreement, but shouldn't there be a theology, a thought-out faith, which serves to train future priests to enlighten Christians? Could it be left to Marxism alone to interpret "temporal realities" and their progress? 

As he explains in the prologue, this reflection justifies this B essay in two volumes. The first, Preludes, sets out the topic in depth, and the second is devoted to the Theology of History (1939), which we will comment on later. As always, Thils makes a great map of topic, which is, in itself, a contribution.

It is divided into four parts. The first three are the preparation and framing of the questions; the fourth is an outline of a Christian judgement of the main "earthly realities". It takes into account Maritain's essay (Integral Humanism, 1936), on the Christian role in a society that is no longer officially Christian; and a article by the Jesuit Montcheuil, Christian Life and Temporal Action (1943), as well as other writings that express the concern to be present in the shaping of the new world. 

He begins by pointing out that Christian philosophers, theologians and sociologists "form a very homogeneous chorus to demand from theological science indications about the value of the world, of the universe of human societies, of civilisation" (14). Catholics, Protestants and Orthodox (Boulgakov, Berdiaev). Even quotation to Donoso Cortes: "A civilisation is always the reflection of a theology". 

The second part provides theological elements of judgement, entering into the oppositions and paradoxes: God and the world, the sacred and spiritual and the profane, the spirit and the subject, the flesh and the spirit. It takes meditation and a lot of nuance to bring things into focus. 

The third part sample the great movement from God's creation, with the mystery of sin and redemption, to the consummation in Christ, through the work of the Holy Spirit. This is where these realities must be framed. 

There is God's creative design for human action in the world (which prolongs his creation), there is sin that deforms, and redemptive action that heals, and there is eschatological and transcendent tension towards the end: one cannot make a world that remains closed in on itself. 

And in this framework, Gustave Thils is convinced that the action of the Holy Spirit in the world is not limited to the inner sanctification of individuals and the liturgical action of the Church, but embraces the whole of creation wounded by sin. Christians must participate in this movement from their place in the world. 

The fourth part, called "simple sketches", which is the longest, applies all that has been seen to some great earthly realities: the constitution of societies, culture and civilisation, technology, the arts and the human work . In each case it is a question of understanding their place in the extension of God's creative action, of thinking about how they are affected by sin, healed by redemption and directed by the Spirit towards the glory of God. 

For example, on work. Relying on St Thomas, he says that every work participates in the divine action, in his causality, and is an extension of his creation. The creative aspect underlines that the human being is the image of God. Certainly, he is touched by sin, but work is not a consequence of sin, it is only a consequence of its painful aspect. And precisely for this reason, it can also have a redemptive aspect. "To restore a society, culture or art is to transfigure it according to the Holy Spirit: this is not just a promise, it is actually realised. [...] That is why the human activity that transmits redemption to the earthly world is, by the same token, a redemptive activity" (191). 

"Uniting all the forms of earthly redemptive activities and uniting them with the theological and theocentric activities of the interior life will give a fairly complete view of what the 'Christian life' as a whole is, with all the universality it possesses in God and in the Spirit" (194). It is necessary to flee both from a "humanisation of Christianity which turns it into a force of moralisation [...] and from a total disembodiment of Christianity by a one-sided insistence on a grace which would not mingle at all with the world in order to penetrate and transform it. [...] It is necessary to think in the light of Christ the treatise on Christian anthropology, the reform of which will perhaps be the greatest work of the twentieth century" (198). These are the last words. 

Twelve years later, in his Current Orientations in Theology (1958), he summarised topic. "We are no longer in the times when the idea of perfection was linked to that of 'monasticism' or 'convent' [...]. The laity are immersed in the temporal and tied to earthly tasks. Their duty of state - which is the first means of sanctification - leads them to give visible attention and vital interest to development of the profane world [...]. This world, in a precarious and transitory way, is the place in which they must sanctify themselves" (quoted from Troquel, Buenos Aires 1959, 133). Orientations are needed to "consider this world with the eyes of revelation, helping them to adapt their gaze to God's gaze". " A theology of temporal realities can help to understand the end of the temporal work and to fulfil it" by knowing how the image of God is realised in the world. "In the last analysis it is a 'Christian anthropology'", but "integral", not reduced to the description of the soul and the interior role of grace. " If our theological anthropology had been 'integral', there would never have been the problem of the theology of temporal realities" (135). 

He expanded by collecting bibliography that had grown up. First the "theology of everyday life", where he quotation Jesus Urteaga(The divine value of the human), Mouroux, Scheler, C. S. Lewis. Then on the body (Mouroux, Poucel), the work (Haessle, Chenu), the family and society (Dubarle, Journet); also art and technology. 

As we have said, the second volume of the Theology of Earthly Realities is dedicated to the Theology of History (1949) and to the eschatological aspect, that is, it asks whether human action in the world and its progress have any relation to the establishment of the Kingdom of God now and at the end of time (the new heavens and the new earth). 

Histories of theology tend to divide authors into "eschatologists" and "incarnationists". "Eschatologists" (Daniélou, Bouyer) would be those who centre the meaning of history on the spirituality and life of the Church, the rest being ancillary or even, in a different Degree, subsumed to the "world" as a reality opposed to salvation. "Incarnationists" (Thils, Chenu and later Metz and liberation theology) would be those who give transcendent and eschatological value to human realities, where they understand that the Kingdom is initiated. They differ and, in fact, Daniélou criticised Thils as "too optimistic". But the question, so rich and complex, is not well reflected in such a simple bipartite division.

Gaudium et spes, which devotes a chapter to human action in the world (nn. 33-39), prudently echoes all this in n. 33: "A careful distinction must be made between temporal progress and the growth of Christ's kingdom", but the former can help and "is of great interest to the kingdom of God". Moreover, "the goods of human dignity, fraternal union and freedom; in a word, all the excellent fruits of nature and of our efforts, after the Spirit of the Lord has spread them over the earth and agreement with his command, we shall find them again", transfigured in the consummation of Christ.
Christ.