The Theological Roots of Thought Experiments in the Middle Ages

Prompted by a fruitful exchange on the Facebook, here’s some historical notes on the roots of thought experiments.

Perhaps the most important event in the history of thought experiments comes in the surprising form of a condemnation of a specific style of natural philosophy – the Condemnation of 1277, issued by Etienne Templar. This condemnation had as its focus a number of Aristotelian propositions, all of which were taken to impugn on the power of God to do whatever He wanted (so long as it didn’t involve a logical contradiction), which included God’s inability to create multiple and different worlds from the actual world, the necessity of all things that happen in the actual world, and constraints on God’s ability to move the heavens in a rectilinear way.

An immediate consequence of the Condemnation was a focus on God’s power for ‘natural impossibilities’ – events with conditions that were impossible from within the received Aristotelian physics. Out of this focus developed two senses of the hypothetical: one concerned with defending Aristotle, the other with moving past him.

The former can be most clearly illustrated by Albert of Saxony:

‘In the fourteenth century, for example, Albert of Saxony, an influential scholastic arts master and natural philosopher, assumed the truth of the eternity of the world and also the existence of a fixed quantity of matter in the world. From these assumptions, he concluded that over an infinite time, this limited quantity of matter would have to furnish bodies for an infinite number of souls. In the course of an eternal period of time, the same matter might serve as the human body of a number of different souls. On the day of resurrection, however, when every soul receives its own material body, a finite quantity of matter would have to receive an infinite number of souls. This was a heretical state of affairs, because one body – indeed every body – would have to receive more than one soul. Albert’s response to this dilemma was typical for natural philosophers who had to contend with theological restrictions. He explains that “the natural philosopher is not much concerned with this argument because when he assumes the eternity of the world, he denies the resurrection of the dead.” Albert simply dropped the inconvenient theological consequences from his discussion but retained the eternity of the world for the sake of the argument. By such appeals and devices, medieval natural philosophers could assume the truth of almost any condemned proposition, provided that they did not proclaim it to be categorically or philosophically true.’ (Edward Grant, ‘The Foundations of Modern Science in the Middle Ages’, p. 80-81)

The more significant sense of the hypothetical, however, turned on God’s power to do anything short of a logical contradiction. This had the effect of encouraging speculation about the world and the way it could be, even though it was ‘naturally impossible’ given Aristotelian physics. The key point to note here isn’t that Aristotle was overthrown or subverted. By using God’s power as a vehicle for speculative natural philosophy, an important meta-counterfactual began to come into view: that the world could coherently be conceived in non-Aristotelian terms. Counterfactuals ‘according to the imagination’ soon became a hallmark of late medieval thought:

‘Natural philosophers actually devised an expression to epitomize this approach when they referred to such counterfactuals as secundum imaginationem, that is, “according to the imagination. The Condemnation of 1277 played a significant role in generating counterfactuals. Many of the condemned articles compelled the acknowledgement of God’s absolute power to do whatever he pleased short of a logical contradiction. Examples of counterfactuals that were derived from the Condemnation of 1277 include the possibility of other worlds, vacua within and beyond our world, and the possibility that God might move our world with a rectilinear motion. In each of these examples, medieval natural philosophers sought to derive consequences within an assumed framework of Aristotelian physics, even though what they initially assumed was impossible in Aristotle’s system. What emerged were a series of interesting speculations, or, as we might say, thought experiments, in which certain Aristotelian principles were challenged and, to some extent, subverted.’ (p. 147-148)

From these counterfactuals emerged new conceptualizations of the world, many of which would be inherited by the early moderns and which would give impetus to the scientific revolution. By clearing the space for non-Aristotelian concepts of the world to be coherently conceived, the groundwork was laid for the assumptions that would drive the scientific revolution:

‘A significant natural impossibility that derived from the condemnation of 1277 involved Article 49, which made it mandatory after 1277 to concede that God could move the world rectilinearly, despite the vacuum that might be left behind. More than an echo of this imaginary manifestation of God’s absolute power reverberated through the seventeenth century. When Gassendi declared that “it is not the case that if God were to move the World from its present location, that space would follow accordingly and move along with it,” he was using the supernatural motion of the world as a convenient support for his belief in the absolute immobility of infinite space. As spokesman for Isaac Newton, Samuel Clarke (1675-1729), in his dispute with Leibniz, also defended the existence of absolute space when he argued that “if space was nothing but the order of things coexisting [as Leibniz maintained]; it would follow that if God should remove the whole material world entire, with any swiftness whatsoever; yet it would still always continue in the same place.” Finally, the power of counterfactuals is nowhere more impressively illustrated than in the principle of inertia, which Newton proclaimed as the first law of motion in The Mathematical Principles of Natural Philosophy (1687): “Every body continues [or perseveres] in its state of rest, or of uniform motion in a right line, unless it is compelled to change that state by forces impressed upon it.”  In medieval intellectual culture, where observation and experiment played negligible roles, counterfactuals were a powerful tool, because they emphasized metaphysics, logic and theology, the very subjects in which medieval natural philosophers excelled.’ (197)


Notes on the Analogy of Being, Barth and Torrance

– T.F. Torrance bases most of his theology on the fact that the Word can’t be divorced from God’s act or being. Torrance also very forcefully rejects any system of theology or philosophy that purports to arrive at God based on study of nature. Torrance rejects it on the grounds that such a system would be independent of any actual knowledge of God as revealed in the Incarnation. However, if the Word became flesh, and it was through the Word that the world came into being, and the intelligibility of creation comes through the Word, couldn’t it be argued that a study of nature is, in a way, a study of God through the Word? Maybe. Maybe not.

– Torrance and Barth both tend to see the goal of natural theology as arriving at God – once you accept the arguments, or the arguments convince you, that’s it – you’re there. But a study of the history of natural theology reveals two things: that God, whether in Scholasticism, Patristic thought, Reformed thought, etc, is never something that can be simply arrived at but something we are continually striving to. Second, natural theology is less about reaching God than it is about exploring the reality of God. Perhaps this is an oversimplification but I see this as an accurate diagnosis of the pathos behind these views.

– A mistake that I see Torrance and Barth making is taking apophatic theology to be a positive statement of what can be ascribed to God (‘nothing’) when apophatic theology is in fact a limitation of what can be positively ascribed to God. It also recognizes humility in theology – the limitations of the human mind. However, as Pelikan notes, this same limitation is also a freedom – it frees the mind to explore the reality of God within the boundaries of apophatic theology. The analogy of being, as well, serves as a boundary:

‘And to this extent, it bears an analogy to the kind of natural theology that Barth rejected. Again, however, anticipating our response to Barth in the final section, the ultimate point of the analogia entis is precisely to humble all natural (and even all supernatural) knowledge of God, to deconstruct every closed system (whether philosophical or theological), in short, to break to pieces every conceptual idol, and to insist that all our knowledge of God, no matter how exalted by grace, is ‘patchwork’ (cf. 1Cor 13:12)—a knowledge in ‘images and likenesses’ that break and fail and thereby point to a God who is beyond comparison, indeed, ‘beyond all analogy’.

– What Barth and Torrance both acutely realize is the effect of mans fallen condition in knowing God – the heart is turned inwards upon itself (as well as the mind) and so any natural revelation can be darkened in a flash, and turned into an idol. This is all too often what happens.

Note on God as Sustaining Cause

From a Facebook comment:
By ‘sustaining the universe’ is meant that God upholds the universe in *being* at every instant, such that if his sustaining activity ceased for even an instant everything would cease to exist. This is an idea common to pretty much every theological tradition, from Thomism to Calvinism. Medieval philosophers worked out some incredible theories of celestial motion, mechanics and kinetics, none of which involved God directly intervening.

So no, it does not mean that God physically intervenes, in say, the orbits of the planets – contra Newton, who asserted that God did in fact intervene to keep the planetary orbits consistent. In fact, his entire program of physics was theological, with time and space being the divine sensorium, or how God was presented to the world/universe/whatever. Newton’s formulation of laws are very theological, in fact, and represent a radical departure from the Aristotlean conception of ‘laws of nature’ which was more concerned with immanent teleology.

Now, with regard to intervention of the divine kind, the classical picture holds to what is usually called primary causality:

‘Providence works at the level of what Aquinas would call primary causality: that is, it is so transcendent of the operation of secondary causes- which is to say, finite and contingent causes immanent to the real of created things…’ (David Bentley Hart, ‘The Doors of the Sea’)

Hence, the natural order of things doesn’t simply run off its own steam, a la deism. The primary cause of things is the source of the secondary causes (secondary causes being what we normally think of causes, gravity, human agency, etc) but also transcendent of it. The difference between this and deism is pretty big. God as the sustaining cause of all that is, then, refers to both his upholding of all existence as well as the grounding of all secondary causes in him.

Thinking About Natural Theology

In the previous post I laid out the basic Barthian line of thought on natural theology – here is T.F. Torrance to break it down a bit further:

‘So it is with natural theology: brought within the embrace of positive theology and developed as a complex of rational structures arising in our actual knowledge of God it becomes “natural” in a new way, natural to its proper object, God in self-revealing interaction with us in space and time. Natural theolog then constitutes the epistemological “geometry” as it were, within the fabric of “revealed theology” as it apprehended and articulated within the objectivites and intelligibilites of the space-time medium through which God has made himself known to us. As such, however, natural theology has no independent status but is the pliant conceptual instrument which Christian theology uses in unfolding and expressing the concept of real knowledge of God through modes of human thought and speech hat are made rigorously appropriate to his self-revelation to mankind.’ (T.F. Torrance, ‘Reality and Scientific Theology’, p. 39)

Right. So basically what Torrance is saying that natural theology, insofar as it will bring us to real, intimate, relational knowledge of the living God, has to be based in actual concrete Christian experience. Apart from actual communion with God, natural theology (in Torrance’s view) is both the product of and leads to a harmful deism. So, then, contrary to the bulk of natural theology as classically understood, natural theology isn’t a preamble to faith but depends on faith to be any kind of meaningful enterprise

More Natural Theology

It seems that the question of natural theology is one of epistemology, specifically epistemological method. No one denies that the heavens declare the glory of God, etc – the question is can/how one to know of God through nature. Here I think it’s important to get a line on exactly what one means by ‘natural’. I take ‘natural’ to refer to human nature before the fall – this was our ‘natural’ state. I would take a Bonhoeffer-esque line in this regards – which means I would hold that, contra (say) Aquinas, our natural state, our created state, did not include knowledge of good and evil – our knowledge of good/evil is a product of our fallen nature which comes as a result of Adam and Eve’s eating of the fruit in the Garden. To quote a friend (this was in reference to natural law, but the principle applies here since it relates to how one comes to know the good):

‘He writes His laws upon the heart not because after the fall Knowledge of Good/Knowledge of Evil was now a delectable, nutritious, and healthy adjunct to the Tree of Life, but because He is in our very being, drawing us, such that if anything we do is good it was itself wrought in God (Jn. 3:19-21), “for in Him we live and move and have our being” (Acts 17:28).’

This has to do with epistemological method – how does one come to know truths in theology? For Aquinas, foundationalism is in play – one can arrive at certain truths (aspects of the natural law tradition as exemplified in Aquinas) via pure reason apart from faith – to quote paraphrase Pope Benedict, certain truths of morality can be arrived at by reason alone apart from faith. I would hold with Bonhoeffer that such a position is mistaken, and that apart from the presence of God truth as such cannot be arrived at by pure reason.

Conceiving of God

It’s not uncommon in the philosophy/theology/philosophy of religion world to come across the phrase, ‘how we conceive of God’ or ‘our conception of God’, or any number of variances on that theme. Is God, however, someone we simply conceive of? Is God someone we arrive at in thought?

I go back and forth on this issue – broadly it’s basically debate over the validity of natural theology. Can we get by reason from nature or the world to God? I generally lean towards a no – because I don’t think that God is something that we approach via our intellect alone, though one cannot be a Christian and deny the place of human reason.

I would say that no, God is not someone we conceive of – if our god is a god that we conceive of and not a God who makes Himself known to us then what have is not God but simply our own construct.

Insofar as we genuinely seek God, He will meet us along any road we travel as we seek Him – if we seek Him on the road of science, He will meet us there. If we seek Him on another road, He will meet us there – but we must genuinely seek. This is the ‘burden of seeking’ that Christianity has, as well as the promise it gives. One cannot simply treat God as an intellectual exercise.

Torrance on Natural Theology

“Torrance explicitly critiques the notion of analogia entis – the idea, especially associated with Thomas Aquinas, that there exists some intrinsic likeness between creator and creation arising from the creative action of God. The fact that there exists some form of correspondence between the creator and creation is not due to an inherent relation of likeness, but to the free and gracious decision of God that some such correspondence shall exist. We are thus dealing with an analogia gratiae rather than an analogia entis. There is no intrinsic capacity on the part of nature to convey God, nor is the created element as such part of the content of revelation. For Torrance, revelation must be understood to be self-revelation of God.

“It will thus be clear that Torrance considers a ‘natural theology’ which regards itself as independent of God’s self-revealation as a serious challenge to Christian theology. Natural theology has a place under the aegis of revelation, not outside it. In its improper mode, a ‘natural theology’ is an approach to theology which leads to the introduction of ‘natural’ or ‘commonsense’ concepts into theology without first establishing the warrant for doing so on the basis of revelation. In this sense of the term, Barth was entirely justified in critiquing natural theology…

“In this sense, ‘natural theology’ must be regarded as a serious threat to responsible Christian theology.” (190)

“It will be clear that Torrance’s careful discussion of the manner in which the creation can be said to have revelatory potential opens the way to some very significant developments. Torrance insists that creation can only be held to ‘reveal’ God from the standpoint of faith. Nevertheless, to one who has responded to revelation (and thus who recognizes nature as God’s creation, rather than an autonomous and self-created entity), the creation now has potential to point to the creator. The theologian who is thus a natural scientist (or vice versa) is thus in a position to make some critically important correlations. While the neutral observer of the natural cannot, according to Torrance, gain meaningful knowledge of God, another observer, aided by divine revelation, will come to very different conclusions.” (192) Alister McGrath, Thomas F. Torrance: An Intellectual Biography (Edinburgh: T & T Clark, 1999).

(The above quotes were read and taken from

The text above shows in a broad sense the main point of contention in the debate on the validity of natural theology, and expounds a bit on the issue of a ‘point of contact’ that I delved into in a previous post. Obviously, Torrance doesn’t hold that there is such an inherent or ready-made point of contact, and as such apart from faith, nature cannot reveal God. Someone of say a Thomistic frame of mind would deny this point. This is, in my mind, one of the few areas in theology where both sides have equally powerful and persuasive arguments.

For my part, as I noted in an earlier post, I generally end up favoring the Barthian position (sometimes more in spirit than in actual fact), while not going as far as Barth in a wholesale rejection of natural theology. Again, as noted before, philosopher/physicist Fr. Stanley Jaki presents a concept of natural theology that I find myself agreeing with. His position is as strong as Torrance or Barth’s– I would be interested in what Torrance would have to say to someone like Jaki. I actually imagine that as being one of the most fascinating conversations one could listen in on. (For those not familiar with Jaki:      )

More Thoughts on Natural Theology, Science, and God

‘The fall had cosmic relevance, but not in the sense of destroying the investigability of a rationally ordered contingent nature.’ (Stanley Jaki, ‘The Roads of Science and the Ways to God,’ p.135)

The above quote I take to be true – we are capable of investigating the physical reality in which we live. The question of natural theology, however, is whether or not such inquiry can, apart from revelation, lead us to God.

Theologically, I think the answer is a firm ‘no’. While the heavens declare the glory of God, they are not God. St. Paul makes the point in his letter to the Romans that because of mankind’s propensity for sin (the heart turned inwards upon itself, to borrow language from the Reformation) such inquiry instead of leading man to God leads man to worship creation instead of God and to the denial of God. Man’s natural knowledge of God (to borrow from Calvin, his sensus divinatis) which would lead to a knowledge of and relationship with God under ideal circumstances, has been damaged by sin:

‘…Aquinas suggested that in response to the faint whispers of the sensus divinatis, humans might respond by positing an ultimate natural principle. That is, the sensus divinatis might be the cause of our belief in laws of nature. Scientists often speak as if natural laws – like the law of gravity – cause objects to behave in a certain way; yet natural laws…are merely our descriptions of the way objects behave. Perhaps this is an example of Paul’s words, “They exchanged the truth of God for a lie, and worshipped and served created things rather than the Creator.” Like all idols, these laws might simply be placeholders for God.” (Mitch Stokes, ‘A Shot of Faith to the Head,’ p. 53-54)

The point being made is that natural theology, apart from revelation, given the inward turning of the heart upon itself from sin, cannot lead us to God – to paraphrase Kierkegaard, the truth must come from outside man.

This is not to suggest that God cannot work through a study of nature to effect someone’s salvation – it is to make the point that a purely natural theology apart from revelation cannot lead one to a knowledge of and relationship with God. Science can be a road that leads to the way to God, but it cannot be the way to God, simply because God is not a scientific principle to be arrived at via reasoning but rather a Presence which must be sought with all the heart, soul and mind.

Thoughts on Natural Theology

Natural theology is what we can determine about God apart from any revelation. Historically there has been some intense debate over the place of natural theology in the Christian tradition – does it even make sense to try and come to any conclusion about God without revelation, by our reason alone? Is it even possible?

Thomas Aquinas, typically regarded as the high point of natural theology, would affirm that it is possible to come to conclusions about God via reason alone apart from revelation. Aquinas’s reasoning, broadly, falls under the ‘analogis entis’, or analogy of being, which roughly means using our own existence as an analogy to understand God’s being. From our own existence, we work towards an understanding of God’s existence.:

‘In 1934, the Swiss theologian Emil Brunner published a work entitled ‘Nature and Grace’. In this work, he argued that “the task of our theological generation is to find a way back to a legitimate natural theology.” Brunner located this approach in the doctrine of creation, specifically in imago Dei, the “image of God”. Human nature is constituted in such a way that there is an analogy with the being of God. Despite the sinfulness of human nature, the ability to discern God in nature remains. Sinful human beings remain able to recognize God in nature and in the events of history, and to be aware of their guilt before God. There is thus a “point of contact” for divine revelation within human nature.”

In effect, Brunner is arguing that human nature is constituted in such a way that there is a ready-made point of contact for divine revelation. Revelation addresses a human nature which already has some idea of what revelation is about. (Alister McGrath, ‘Christian Theology: An Introduction’, p. 191-192)

Karl Barth violently opposed this idea – and historically, the Reformed tradition in general has rejected natural theology of this kind, though not as angrily as Barth did. For Barth, the ravages of sin destroy any ‘point of contact’ present in humanity. ‘The Holy Spirit needs no point of contact other than that which that same Spirit establishes’, was Barth’s reply. In a word: Nein!

Brunner presents a fairly powerful argument here, though, which demands an equally powerful rebuttal. Thomas Torrance argued along Barthian lines against such a natural theology:

‘…all rational explanation must presuppose a basic continuity here between man and God, but that is just what the atonement reveals to be our wanting by the very fact that God Himself had to descend into our bottomless pit of evil and guilt in order to construct continuity between us and God.’ (T.F. Torrance, ‘Atonement: The Person and Work of Christ,’ p. 4)

The contention here, to simplify, is this: can God be known from nature by human reason, or, to argue from a more Barthian-Torrancean (and I would say orthodox) perspective, can God absolutely not be known from nature?

As a side-note, Fr. Stanley Jaki, who is quoted enough here that hopefully the few readers I have are somewhat familiar with his thoughts, brings an interesting perspective on natural theology and science that I’ll also take a look at in the near future.