The famous Prussian philosopher Emmanuel Kant (1724-1804) has left a personal testimony of an honest and hard-working person. More sympathetic and social than a badly chosen anecdotal record has sometimes shown. Of humble and Protestant origin, and with an intellectual commitment and a moral seriousness that he never renounced, although he lost faith in Christian revelation and perhaps in God. Some fragments of his Opus postumum (ed. 1882, 1938) may give that feeling, which is difficult to assess.
Kant's enlightenment
He is the most representative illustrated and, at the same time, the least, because the others are neither so deep nor so serious. And he was not a Freemason. And besides, there are many Catholic ilustrados (Mayans, Feijóo, Jovellanos...). But he defined What is illustration (1784), summarizing it in the motto "dare to know". (sapere aude). This meant becoming intellectually adult and freeing oneself from tutors and tutelage (and also from Prussian and Protestant state censorship) to think on one's own and to seek knowledge in all authentic sources. This ideal could be assumed and was assumed by Catholics in all natural knowledge. Aware, however, that we need God's revelation in order to know the depths of the created world and of ourselves, and also to save ourselves in Christ.
But Kant, like many of his time and ours, did not trust the Christian historical testimonies. And so he wanted to detach the Christian religion from its historical foundations (Jesus Christ) and thus composed Religion within the limits of reason (1792). Reducing Christianity to a morality without dogma, and having wide repercussions in the Protestant (Schleiermacher) and Catholic (modernism) worlds.
It is said that, just as Catholic thought depends on Aristotle Christianized by St. Thomas, Protestant thought depends on Kant Christianized by Schleiermacher (1768-1834). The difference is that to St. Thomas The vocabulary of Aristotle helps him to think and formulate well the Trinity and the Incarnation, while for Schleiermacher, the agnosticism of Kant forces him to convert the Christian mysteries into brilliant metaphors. All that remains is the human conscience before the absolute and Christ as the ultimate realization (at least for the moment) of that position. And the commandment of neighborly love as an aspiration to universal brotherhood, which is what the Protestant liberalism that follows Schleiermacher will summarize as follows The essence of Christianity (1901, Harnack).
But the Catholic Guardini will remind you that The essence of Christianity (ed. 1923, 1928) is a person and not an idea, Jesus Christ. That this Jesus Christ is The Lord (1937), Son of God, with whom we are united by the Holy Spirit. And that all this is celebrated, lived and expressed in the sacramental liturgy of the Church (The spirit of the liturgy, 1918).
The Critique of Pure Reason
In Kant's philosophical background two traditions collide: on the one hand the rationalist tradition of Spinoza and Leibnitz, but above all that of Christian Wolff (1679-1754), today almost unknown, but author of an encyclopedic philosophical work with all the specialties and metaphysics, centered on God, the world and the soul. Kant did not know directly neither the medieval scholastic nor the classical Greek tradition (he did not read Greek). Therefore, his Critique of Pure Reason (ed. 1781, 1787)above all, it is critical of Wolff's rationalist method and his metaphysics.
This clashes with English empiricism, especially that of Hume (1711-1776), with its radical distinction between the experience of the senses (empirical) and the logic of notions, which give rise to two types of evidence (Mater of fact / Relation of ideas). And his critique of key notions such as that of "substance" (notion of the ontological subject), which includes the self and the soul, and that of the "causality". For Hume, one cannot turn a bundle of experiences of the self united by memory into a subject (a soul) and neither can an empirical and habitual succession into a true "rational causation" where the idea of one thing logically compels another. To this is added Newton's physics that discovers necessary behaviors in the universe with mathematical laws. But how can there be a necessary behavior in the universe? "necessary" in an empirical world?
Kant will deduce that the forms and ideas that reality cannot give, because it is empirical, are held and put by our faculties: sensibility (which puts space and time), intelligence (which holds and puts causality and the other Kantian categories) and reason (pure) which handles the ideas of soul (self), world and God, as a way of coherently uniting all internal experience (soul), external (world) and the relation between both (God). This means (and this is what Kant says) that the external experience puts the "matter" of knowledge, and our faculties give it "form". Thus, what is intelligent is set by our spirit and it is not possible to discern what lies beyond. This is not recognized by Kant, but later idealism will take it to the extreme (Fichte and Hegel).
Catholic reactions
– Supernatural Critique of pure reason immediately aroused a powerful reaction in Catholic circles, especially among Thomists. Often intelligent, sometimes inelegant. It was probably the milieu that devoted the most attention to it, aware of what is at stake. Although Kant's immediate reference is Wolff's metaphysics (and that produces some distortions), the whole of classical metaphysics (and the theory of knowledge) is affected. This effort even gave rise to a subject in the curriculum, called, as the case may be, Epistemology, Critique of Knowledge or Theory of Knowledge.
The Thomistic tradition, with all its scholastic logical arsenal, had finer instruments of analysis than those used by Kant, although Kantian analyses also sometimes overwhelmed them. With a certain ignorantia elenchiKant reproposes the immensely debated scholastic problem of universals. That is, how is it possible for us to obtain universal notions from the concrete experience of reality. This requires a very good understanding of abstraction and separation, and induction, operations of knowledge very much studied by scholasticism. Also, the "entities of reason" (such as space and time) that have a real basis and can be mentally separated from reality, but they are not things, nor are they prior forms of knowledge.
The Jesuit Benedict Stattler published a Anti-Kantin two volumes, as early as 1788. After that, there have been many more. It is worth noting the attention paid to it by Jaime Balmes in his Fundamental Philosophy (1849), and Maurice Blondel in their Notes on Kant (in The idealistic illusion(1898), and Roger Vernaux, in his commentary on the three critiques (1982) and other works (such as his Kantian vocabulary). Also the Catholic writers of the great histories of philosophy, who dedicate important and serene critiques to him. Teófilo Urdánoz, for example, devotes 55 pages of his History of philosophy (IV) to the Critique of pure reasonand Copleston almost 100 (VI). Of course, Kant has made the Catholic world think a lot.
The Critique of Practical Reason
As well as the Critique of pure reason ends up in a certain (though perhaps productive) tongue twister and in a vicious circle (because there is no way of knowing what we can know), the Critique of Practical Reason (1788)is an interesting experiment of what pure reason can establish autonomously in morality. Of course, it should be said at the outset that morality cannot be deduced entirely by reason, because in part it is drawn from experience (for example, sexual or economic morality) and there are also intuitions that make us perceive that something hits or does not hit, or that there is a duty of humanity or that we are going to do harm. But Kant tends to disregard what appears to be "sentimentality"because it intends to be entirely rational and autonomous in discovering the universal rules of action. This is its merit and, at the same time, its limit.
As the first categorical imperative (something self-evident and self-imposed), it will state: "Act in such a way that the maxim of your will may always be valid at the same time as the principle of a universal legislation.". A valid and interesting principle in the abstract, although in its practical implementation in the consciousness it demands a scope and an effort that in many cases is impossible: how to deduce all daily behavior from there. A second principle, which appears in the Basis of the Metaphysics of morals (1785), is: "Man, and in general every rational being, exists as an end in himself, not only as a means to whatever uses of this or that will; he must in all his actions, not only those directed to himself, but those directed to other rational beings, always be considered at the same time as an end." (A 65).
For this felicitous formulation alone, Kant deserves a great place in the history of ethics. John Paul II, when thinking about the foundations of sexual morality, relied heavily on this maxim to distinguish what can be a disrespectful use of another person, or, put positively, so that sexual life is always dignified, just and beautiful treatment between people (Love and responsibility, 1960). And it gave rise to what the then Karol Wojtyla, professor of morals, called "personalistic norm". To the Kantian consideration, he added that the true dignity of the human being as a child of God demands not only respect but also the commandment of love. Every person, because of his personal dignity, deserves to be loved.
There is another striking aspect to the Kantian attempt at a rational and autonomous morality. These are the "three postulates of practical reason".. For Kant principles necessary for morality to function, but undemonstrable: the existence of freedom, the immortality of the soul and God himself. If there is no freedom, there is no morality. If there is no God, it is not possible to harmonize happiness and virtue, and to guarantee the success of justice with due retribution. This also demands the immortality of the soul open to a perfection here impossible. This recalls Benedict XVI's commentary on the foundations of political life, which need to be etsi Deus daretur, as if God existed. Rational morality can also only work etsi Deus daretur.
Finally, the reference that Kant makes in different places to the "radical evil". The evidence, so contrary to adult and autonomous rationality, that human beings, with astonishing frequency and with full lucidity, do not do what they know they should do or do what they know they should not do: St. Paul's experience in Romans 7 ("I do not do the good I want to do, but the evil I do not want to do."How to understand it? And, even more, how to solve it?
The transcendental Thomism of Marechal (and Rahner)
The Jesuit Joseph Marechal (1878-1944) was a professor at the Jesuit house in Louvain (1919-1935), devoted much attention to Kant and reflected this in the five volumes of his work The starting point of metaphysics (1922-1947) published by Gredos in one volume, and translated among others by A. Millán Puelles. Especially in the IV volume (French ed.), Maréchal paid attention to the Kantian theme of conditions a priori or conditions of possibility of knowledge.
Karl Rahner (1904-1984), always attentive to the latest in the intellectual panorama, took some notions and vocabulary from Maréchal's transcendental Thomism. Above all, the "conditions of possibility". His fundamental theology is based on this, because he thinks that human understanding is created with conditions of possibility that make it capable of revelation and, to that extent, are a kind of revelation. "athematic" already implicit in the understanding itself. And it is what makes all men to be, in a certain way "anonymous Christians". The criticism that will be made is that the understanding itself, such as it is, is already capable of knowing the revelation that is given to it in a way that is adequate to the human way of understanding, "with deeds and words" (Dei verbum). All human beings are "anonymous Christians"not because they already are, but because they are called to be.
Thus, in many ways, Kant has made Catholic philosophers and theologians think and work hard, even if it is difficult to make a general assessment of the results because of the immense breadth and complexity of the topics.
