I.

The most commented passage of Aquinas's Summa Theologiae is undoubtedly the well-known one (I, 2, 3) which contains the so-called ‘Five Ways’ — five famous proofs of the existence of God.^{Footnote 1} The fourth proof, however, seems to have been less commented on than the others and is often considered somewhat apart. Here is the argument of the Fourth Way:

Christopher Martin says: ‘I don't think I understand the Fourth Way, and have even less confidence in my ability to make it out as an argument that proves the existence of God’. He adds: ‘I console myself by the consideration that I am in good company: both Kenny and Geach seem to give up on the Fourth Way’.^{Footnote 3} Peter Geach finds the argument ‘odd and obscure for a modern reader’^{Footnote 4} which is not an unequivocally damning verdict. Anthony Kenny speaks of ‘absurdity,^{Footnote 5}’ which is surely a clear condemnation. Both authors seem to assume that the difficulty or even the supposed flaw in the argument could be due to its latent Neoplatonism.

For anyone who claims to say anything about the Fourth Way, these negative judgments about it by such famous commentators are obviously as intimidating as Aquinas's text itself. I would like to show first that the argument of the Fourth Way appeals to a certain use of language which is not uncommon. I'm not sure that this argument invokes (as is sometimes claimed), a sophisticated metaphysical theory such as Neoplatonism. At the very least, the reasoning of the Fourth Way need not be viewed as an argument reserved for Neoplatonists. Rather, it could be taken to employ a quite commonsensical way of thinking.

Secondly, I will try to give some credit to the idea that it would have been possible for Aquinas to add beauty to the brief list of these three properties, true, good, and noble, from which Aquinas claims that we can give meaning to the term ‘God’ in the affirmation that ‘God exists’. The Fourth Way could then be understood as, let's say, an ‘Aesthetic argument’ for the existence of God. We could pass from beautiful things (things that we say are beautiful, using the predicate ‘beautiful’) — or, more exactly, from more or less beautiful things, to what we call ‘God’.

II.

Paul Weingartner recently proposed a formal reconstruction of the Fourth Way which tends to suggest that it does not suffer from logical flaws and that its argument, if one accepts the premises, is perfectly conclusive.^{Footnote 6} But it is not my project here to assess the logical merits of the Fourth Way. I am even temped to think that it is not so important to check if the Way proves the existence of God in the way that a theorem is proven. It seems to me possible, even preferable, to think that Aquinas offers the Fourth Way as an explanation about what meaning is given to the statement ‘God exists’ by those who believe it is true and claim it to be true (people such as the young Dominicans who were the first recipients of the Fourth Way). In my view, the Five Ways as a whole are not proofs, in the sense that anyone understanding the premises would be absolutely bound to accept the conclusion or would be crazy not to. The Five Ways are explanations intended to indicate what the one who says that God exists is talking about. Of course, the explanations should not be irrational (or logically foolish), and they have to be understood by an open-minded person.

Imagine this situation. Someone uses the word ‘God’. She is told, ‘But what do you mean by God?’ She responds with the explanations found in the Five Ways. And she says: ‘This is what we call God’, according to each of these ways to speak about ‘God’. The Five Ways are then ways to give a meaning to the term ‘God’, as Christians and even some non-Christians do. Herbert McCabe said that ‘to assert that God exists is to claim the right and need to carry on an activity’.^{Footnote 7} It is an activity of wondering about God, especially about the way we can talk about Him, and also to ask questions about the world as it is, about us, about what all things lead to, about the way it is better to live, etc. All these topics are ones with which the Summa Theologiae is concerned. McCabe adds that ‘a belief in God — in the sense of a belief in the validity of the kind of radical question to which God would be the answer — is a part of human flourishing and … one who closes himself off from it is to that extent deficient’.^{Footnote 8} If it is a question of determining how one can have this belief, we are above all led to say what it is we call ‘God’.^{Footnote 9} And the Five Ways do this. But what is so special about the Fourth one?

III.

In the Fourth Way, as in the other Ways, what is first pointed out is an observation that everyone is supposed to be able to make. This observation in no way presupposes knowing Neoplatonic metaphysics. On the other hand, it does suppose mastering the use of certain scalar predicates, those which admit degrees. One must be able to make an evaluative description of reality: to make it in terms of what is better or worse. In the argument of the Fourth Way, we are told that if we use predicates such as ‘good’, ‘true’, and ‘noble’, it is on the assumption that things can be said to be more or less F because they ‘approximate in various ways to what is most F’. I will suggest adding ‘beautiful’ among these F-predicates, even if Aquinas does not cite this predicate in the Fourth Way.

Several commentators do not dispute that we make the observations of which Aquinas speaks. Nor do they contest our mastery of the use of some scalar predicates. But they do ask what could justify going from ‘some things are more or less F’ to ‘there is something that is fully F’. Why, if one thing is greener than another, should there be the greenest thing there is? Again, if some things are more good, true, or noble than others, why should there also be something fully all three? It is the same query when it comes to ‘more beautiful’ and ‘the most beautiful of all things’. Moreover, if some things exist more than others, why should something have to be the most existent one, a Maximal being, the cause of all that is? Aquinas seems to offer no argument to justify such an extraordinary conclusion, or if he tries, it is often suggested today that the argument is very feeble.^{Footnote 10}

Is Aquinas's argument really such a failure? Here, following Peter Geach, is roughly what Aquinas seems to suggest: ‘If any perfection occurs in a thing only to a degree, this requires a real distinction between the individual instance of the perfection and the degree to which that perfection is found’. So, ‘what accounts for the actual degree to which the perfection occurs — i.e., on Aquinas's view, accounts of the esse of that perfection — must be something outside the thing that has the perfection to that limited degree’. It must be ‘something possessing perfections not to a degree but without limit — God, who is “infinite in all perfections” as the Penny Catechism says’.^{Footnote 11}

Geach's reference to the Penny Catechism may signify that the reasoning at work in the Fourth Way is not just that of a professional metaphysician or a scholar of Neoplatonism. It is what an ordinary Christian can engage in or at least repeat. It could even be (why not?) an ordinary piece of reasoning for one who believes in God: she observes perfections in things, admits that they are there only to a certain degree, and thinks that something must not simply have these perfections, but be these perfections. Then, if all things in the world exist only to some degree because they are more or less perfect (being limited, temporal, contingent, etc.), there is a being whose fullness of being is absolute.

However, an objector might say: ‘Be serious, that's not an ordinary thought at all! That's even the worst possible example of metaphysics, the Neoplatonic one. It is obscure (with its notion of degrees of existence) and far-fetched (with strange reasoning)! What Aquinas says in the Fourth Way therefore rests on a very disputable presupposition: if something is more F than another thing, then there must be what is more F than anything else! One understands quite well why among the Five Ways, the Fourth is often the least respected. Whether inspired by Plato or Aristotle, this reasoning is by no means ordinary, and it is simply very bad’.

However, I do not believe that the objector is right here. Let's change the example. Alfred asks how long a certain piece of furniture is. One answers that it is one meter long, or almost. But Paul asks how close exactly it is to a meter. A tape measure is then used. But Alfred replies that we still need to know if the tape measure is one meter long. He is told that the tape measure width is exactly the same as the standard meter preserved in the Pavillon de Breteuil, in the city of Sèvres, near Paris. As Wittgenstein said: ‘There is one thing of which one can say neither that it is one meter long, nor that it is not one meter long, and that is the standard meter in Paris’. Wittgenstein adds that ‘this is, of course, not to ascribe any extraordinary property to it, but only to mark its peculiar role in the language-game of measuring with a meter-rule’.^{Footnote 12} Then, if you say of something that it measures more or less a meter, you thereby suppose that there is something that makes a meter absolutely a meter, fully a meter: it is the standard meter. But the standard meter is not a meter long, but the meter itself.^{Footnote 13}

In the same way, when you say something is good, you therefore assume that something is fully good, or rather that it is Goodness itself. God is not good; God is Goodness. Perhaps Aquinas relies on a whole philosophical (Neoplatonist) tradition, the one that seems to fascinate some commentators and to annoy other ones. Perhaps, as is often suggested, he has in mind the notion of ‘transcendentals’. But when Aquinas says, ‘the truest things are the things most fully in being’, is he not engaging in the same kind of reasoning as we do when it comes to the standard meter? There is something, which is not only what possesses a certain predicate that we observe in things, but is, in act or realized, what we designate by this predicate. Things can be more or less good, true, noble, and beautiful. But there is also what is perfectly good, true, noble, beautiful. And if we can speak of things which exist more or less, does it not follow that there is something which is existence or being itself, something that ‘we call God’?

Of course, God is not somewhere in the sky in the same way that the standard meter is materially in the Pavillon de Breteuil.^{Footnote 14} And there are many good reasons for saying so, in particular that God is not a material thing. But to go from our scalar use of good, true, and noble, and beautiful, to God as not simply good, true, and beautiful, but as goodness, truth, and beauty itself, is no more far-fetched than to say that there is a standard meter. However, to doubt that there is one would be excessive or even stupid!

IV.

It is important to notice that not all predicates are scalar — ‘being born in Brittany’, for example is not scalar since you cannot be more or less born there. And among the scalar predicates, only some are likely to allow for the reasoning of the Fourth Way. It would not, for example, make sense to use a predicate like ‘repugnant’ in the reasoning of the Fourth Way. The observation from which we start in this reasoning derives from our capacity to choose the right predicates and to see that in the world some things really are more or less valuable. One then must be able to apprehend the real value of things: their moral value (goodness), their epistemic value (truth) and their social value (nobility). We must also be able to apprehend the aesthetic value of an object, a situation, or an attitude. The reasoning of the Fourth Way is only possible for those who are attentive and even sensible to values. The world around us is not evaluatively neutral. Things are worth more or worth less.

There are still two conditions for the reasoning of the Fourth Way. First, it is necessary that the predicates ‘true’, ‘good’, or ‘beautiful’ are attributed objectively. (And therefore, that the value given to things, to people, to situations, to attitudes, is not a projection, but concerns many properties that they possess.) All modern aesthetics, especially after Kant, goes against this condition, and it could be ‘odd and obscure for a modern reader’, as Geach says. But that is not a reason to reject it.

Secondly, the scalar predicates do not just designate an actual property of an object X as belonging to some kind — the beauty of a horse as a horse, for example. It has also to mean a beauty which is not that of something in a determined kind: beauty as the real source of all beauty, independently of any kind. Nothing could even be imperfectly beautiful without falling short of what is beautiful absolutely and independently of any kind.

‘Beautiful’ would therefore be a predicative adjective rather than an attributive adjective, to use the distinction promoted by Peter Geach.^{Footnote 15} If the predicate ‘beautiful’ were systematically attributive, beauty would exclusively be the best aesthetic realization of a thing according to the kind of thing it is. (‘Big’ is typically attributive: a big mouse is small compared to a small elephant, and it is not possible to split ‘a big mouse’ into ‘it is a mouse’, and ‘it is big’.) It would exist for each kind of thing a standard of its beauty, and nothing could be perfectly beautiful, or Beauty itself. About attributive beauty, a scholastic philosopher would say ‘beauty secundum quid’, I suppose. The predicate ‘green’ is predicative: using it does not imply that we are talking about a kind of things characterized by their greenness. And, if we are reasoning as in the Fourth Way, speaking of ‘beauty’ we transcend generic membership, as in the case of green. This, perhaps, is a reason to say that ‘beauty’ is a transcendental,^{Footnote 16} ‘beauty simpliciter’. Used then in a predicative way, ‘beautiful’ means a beauty which is not only the one we attribute to things according to their kinds, but something that transcends all beauty of some kinds.

The right question would then be: Where could this beauty, understood as an excess which signifies a degree of perfection in the thing, come from? Aquinas answers in a passage from his Commentary on Dionysius's ‘On the Divine Names’.

The attribution of beauty consists first in noting the excellence of a thing with regard to certain characteristics, integrity, proportion, and clarity, that it possesses. It also consists in identifying the genus or kind to which what we call beautiful belongs. Aquinas and many other scholastics claim (or suggest) that (attributive) beauty supervenes^{Footnote 18} on these physical properties: integrity, proportion, and clarity or splendor.^{Footnote 19} But it only seems to make sense if we know what kind of thing we are talking about: for integrity, proportionality and splendor do seem to depend on the sort of thing that we observe. There is a beauty of each thing in its kind, linked to this attributive use of ‘beautiful’, just as there is a goodness also linked to what it is to be ‘a good X’ or ‘a good Y’. But there is also the predicative use I already talked about. In this use, outside of any kind, we mean not only most beautiful, but super beautiful. And this use means ‘God’ as the one without which nothing would be beautiful, ‘the fountain of all beauty’. In this use, then, beautiful is internally connected to the very nature of God, through the identification of beauty as an attribute or perfection of God.

It is important here to insist on Aquinas's method. It does not proceed by an appeal to a subjective experience of beauty so that the meaning of ‘beautiful’ is explained as a modern philosopher would. Aquinas indicates how we use certain predicates or qualifiers, such as ‘the most beautiful’ (pulcherrimus) and as ‘super beautiful’ (superpulchrum), to characterize something that is not only real, but the most real. As it is a question of correctly using a predicate, what then matters also is our belonging to a language community, in which this predicate while being in use makes sense. And isn't this community of language that which is appealed to in speaking of what ‘we call God?’, as said in the Fourth Way? ‘We’ includes those who are able to use in a certain (right) way the predicates ‘good’, ‘true’, and also ‘beautiful’. These people understand the attributive, evaluative, even superlative use of these predicates. But they also include a use, linked to the previous one, but which this time is predicative, and can then be absolute. To reason as in the Fourth Way with the predicate ‘beautiful’ is to recognize the importance and even value of the religious use of language, when we say of God that He is beautiful. This religious use is learned in the liturgical life and in prayer:

V.

So, I now offer three remarks about beauty. The first concerns a central theme in the understanding of Aquinas's thought: analogy. The second will relate the question of the analogical attribution of beauty to God as plenitude of being with what fully realizes what we are. I mean the virtues. The third concerns the ‘mystical’ meaning that, under certain conditions, it is possible to give to the term ‘beautiful’.

(1) It has often been noticed — and we already know this from Plato in Hippias Major — that we would be hard pressed to find what all beautiful things have in common. And it sometimes leads to the consideration that beauty is not one of these things.^{Footnote 21}

Surely, there is no univocal common standard to which everything we call beautiful refers. (No more than for good, when one says that ‘The cheese is good’, and ‘This person is good’.) But ‘beautiful’ is not equivocal either; we are indeed saying something about what we say is beautiful: we are focusing upon a perfection. The reasoning of the Fourth Way therefore presupposes an analogical theory of meaning, the same one which is developed in question 13 of the Prima Pars of the Summa Theologiae:

It is the whole meaning of the Fourth Way to say that in a predicative use of certain predicates one can signify a perfection, not simply according to a standard given by a corporeal reality, or even a human reality, of any kind, but to mean a plenitude of being; and that it is what makes sense when we say ‘God exists’. I will add that ‘beautiful’ always has an analogical use: a literal, but not univocal, meaning. It is precisely because we know how to use analogical predicates that things in this world can be truly called beautiful. They are beautiful each in their own way, in an attributive way. But also, there is a use of ‘beauty’ that gives a sense to a formula like ‘the beauty of God’, which cannot be attributive since ‘God’ is not a category, with criteria of beauty for all the gods. And note that what matters, therefore, in the observation of beautiful things, leading to giving meaning to what we call God, is not so much an aesthetic experience (what modern philosophers thought it was), as a linguistic competence: a mastery of the analogical use of the term ‘beautiful’, like other terms, ‘true’, ‘good’. (And certainly, certain conditions, linguistic and social, are to be met for this mastery to appear.)

(2) Peter Geach says:

The beauty of things in the world, whether these things are naturally occurring things or artefacts, is related to an excellence of those who apprehend it; and they are better, by apprehending it, according to their own nature as rational beings. ‘Beautiful’ is thus a property that depends on a response. The beauty of things is the occasion of the best realization (or flourishing) of our nature.

The Fourth Way begins then with an observation which presupposes certain dispositions in the person who reads it. This person has to be able to identify certain things as good, true or noble; and that is why she also has to use intelligibly these scalar predicates which express degrees in being. It supposes our attention to what is of value and to what has, in this sense, more being. And what makes this attention possible are our virtues.

A virtue could be defined as ‘an excellence in being for the good’.^{Footnote 24} A virtue causes our desire to be ordered to that which has value. In doing so, the virtues best realize the kind of being we are, rational beings. Certainly, the one who makes this observation about what has value could also be akratic: she may not fully have the virtues. But the one who is sensible to value could not be akolastos. She could not have ‘a corrupt mind’, to borrow an expression used by Elizabeth Anscombe^{Footnote 25} when she characterizes, following Aristotle, someone completely indifferent to all value and perfection. To apprehend beauty is already to be better; and then to be more the sort of being characterized by rationality. We are better by apprehending what is better or beautiful. And being better, we exist more, and we are closer to what (or who) makes all things beautiful when they are, and to what God, who makes them to be. In this sense, a virtue could also be defined as ‘an excellence to be for the beautiful’, and then to be for God. Thus, the apprehension of these properties which in things signify the existence of Truth, Goodness, and Beauty, requires of us an increase, through the exercise of the virtues, in being at the higher degree the sort of being we are.

(3) Then, under certain conditions, ‘beautiful’ has what could be called a ‘mystical’ meaning; it connects us to God. This mystical meaning is not at all irrational since its apprehension presupposes and even consists in the best realization of our rational being through the virtues. It includes a certain quality of our response to beauty and the true existence of a perfection which is not of and in this world, but without which nothing would be beautiful (nor even would exist).

That is what, I think, Herbert McCabe talks about when he says that Aquinas, ‘in what is sometimes misunderstood as his dryly rational approach, even in his arguments for the existence of God, … is in fact engaged in, and inviting the reader to be engaged in, a mystical exploration, which is not at all the same thing as a mystical experience’.^{Footnote 26} By ‘mystical meaning’, I do not mean a rare experience reserved for a few people. It is even something quite common! Someone asks herself why she says a landscape is beautiful, why she says music is beautiful. Of course, her questioning can deviate if she has taken too seriously modern philosophers who invoke a subjective experience (some mental state in which a ‘subject’ finds herself, as Kant says, in a quite mysterious relation with her own mind). Or alternatively, her questioning can also deviate if it invokes exclusively social conventions, cultural practices, without relation to what things really are. Our use of ‘beautiful’ would then in no way correspond to the real qualities of what is said to be beautiful. But suppose we are not diverted by some modern and fashionable theories from thinking (a) that we apprehend a real property of what one says to be beautiful, (b) that it is a perfection at a certain degree, and (c) that there is something that causes the beauty of beautiful things, and whatever other perfection they have, even their being, understood as a perfection. Wouldn't we come to think that it is even what we call ‘God?’ We could speak of a mystical meaning for all those who are capable of an analogical use of ‘beautiful’. And this use is acquired in the life of a community, the People of God, when they pray and engage in the liturgical life — at least when it has given them the means of a liturgical life allowing them to follow the Fourth Way.

This is why the argument of the Fourth Way does not concern so much the most technical metaphysics, doped with Neoplatonism. It is rather what happens in the life of an ordinary Christian, when she walks in the countryside, observes the flowers of the fields and the birds of the forests, listens to music, reads poems. And, eventually, when she appreciates the beauties of the liturgy. Beauty in everything that is related to the Christian life is then crucial for the possibility of the mystical meaning of ‘beauty’ — I mean the beauty of religious buildings, hymns, prayers, liturgical vestments, of the liturgy itself. Today, commentators of Aquinas are more interested than before in his poems, particularly in the liturgy for the feast of Corpus Christi. These texts fit very well in terms of the mystical significance of beauty, and the way we could understand the Fourth Way.

As a compass allows us to turn to the north, beauty turns us to God as the source of all beauty. But that still supposes that we are a compass that works well; it means that we exercise virtues, and then excel in the apprehension of the beauty of things around us and of its mystical meaning.

VI.

An aesthetic way to God has certainly not been totally neglected in recent theology.^{Footnote 27} But it does not proceed by following the process of the Fourth Way and by attributing a ‘mystical meaning’ (without ‘mysticism’) to the predicate ‘beautiful’.

To explain what may have happened so that this Thomist view of the use of ‘beautiful’ was no longer followed, I will add something along the line of that offered by Elizabeth Anscombe, in her famous paper ‘Modern Moral Philosophy’. She claims:

Let's then move from the notion of law to that of beauty. The use of the term ‘beautiful’ was deeply linked to the existence of God as ‘a fountain of all beauty’. Aquinas's Commentary on Dionysius's ‘On the Divine Names’ explains why. But this mystical meaning of ‘beautiful’ has been lost in the same way that, for Anscombe, a certain meaning of the word ‘obligation’ has been lost. For Anscombe, the notion of law was retained, but the divine legislator dismissed. In the same way, we still use the predicate ‘beauty’, but without mystical meaning, and so without ‘reference’ to the source of all beauty. The term ‘beauty’ has been secularized, thanks to modern philosophers (the same roughly as those of whom Anscombe speaks in her famous paper). The desacralization of beauty is mainly a linguistic change. Philosophers tried to find aesthetic standards somewhere other than in God when it comes to the use of ‘beauty’. Especially, following Kant, they thought to find beauty in the supposed particularity of an aesthetic experience.

It is at least still possible to offer another perspective, inspired by the Fourth Way. We see the beauty of the things around us, whether natural or artefactual. This can form a basis for making sense of what we call ‘God’ in the formula ‘God exists’. If we are asked what we mean by saying that ‘God exists’, we could claim that we are saying that certain things are beautiful. And from there, we can add that it makes sense to say that ‘God exists’. If our interlocutors do not find this convincing, isn't that because something has happened concerning the analogical and mystical use of the word ‘beautiful’?

In the same way that Anscombe is credited with having restored all its importance to a philosophy of the virtues, is it also perhaps, by examining the virtues in what one can call our aesthetic life,^{Footnote 29} that a philosophy of beauty could regain its lost meaning?^{Footnote 30}