Saint Thomas Aquinas was right after all, and his Second Way to prove God exists does work. The existence of the First Cause can be demonstrated, and this being can be shown to be God. Just by itself, this one argument of the five turns out to be enough, at least in principle.
For his argument can be reconstructed in terms of "dynamic punch" (or "active energy"), reactivity, and spontaneity. As soon as this is done, the point becomes obvious to anyone who thinks it through. Yet here, as always in philosophy, one must ask the right questions. Otherwise, the attempt to think it through will only lead one astray by going down the wrong path. What, then, should be asked here? Nothing can ever happen in a world where there is only pure passivity. What would have to be added to enable things to happen? In particular, would adding just the power to react be enough, if that were truly and strictly all that were added? Or would there have to be some full spontaneity somewhere to provide the dynamic punch? These concerns are what must be explored here.
In this essay, these considerations are organized under five main headings.
On the Existence of the First Cause
On the Most Popular Objection to This Argument
On the Status of the First Cause
On an Objection Derived from Modern Physics
On the Other More Serious Issues and Questions
Someone with little or no background in philosophy may do well to omit the third, fourth, and fifth of these sections, at least on the first reading.
(From here, you can skip directly to the list
of linked sites.)
(Alternatively, you can go to the bibliographic note first.)
This is the easy part. A world void of dynamic punch is a world in which nothing happens. Since things do happen, there is dynamic punch in the world. But why is this so, or how does this work? Nothing can cause itself to happen or activate itself to work, for nothing can be prior to itself. At least, this is so except insofar as something is already activated or energized in some way. (Only someone who is already partly awake, and not too sick or exhausted, can force himself to come fully awake.) Again, nothing can be prior to itself, and so what nothing can do is to "fire itself up" from point zero. Nor can anything really give to itself any powers or capabilities that it does not already have in some way. (In real life, "pulling oneself up by one's own bootstraps" is at best a metaphor.)
Even so, things happen even apart from the exercise of pure spontaneity. Yet a thing that is more or less inert can still convey dynamic punch by way of reacting to what happens to itself. For example, a domino can knock over another domino in reacting to having itself been knocked. But any series of reactions, however long, is purely derivative and refers back to some exercise of genuine spontaneity to initiate the series. To say there was never any such exercise is to deny the basis for what is happening here and now. As Thomas said, it is like saying there is only the series of instrumental causes, with no principal agent. For that is what it means to say something works only because it is itself reacting.
Of course, there could be various exercises of partial spontaneity on the part of lesser agents who are themselves reacting. For example, living beings may be said to be this way. Again, given that there is free choice of the will, a human agent who engaged in such choice would be doing exactly this. But since these agents are themselves reacting, the same problem exists concerning the causal impacts upon those agents to which they are reacting. Therefore, one must finally come to an agent whose action is absolutely primary and who thus acts with full spontaneity, free from any conditions or prompting. This agent, then, is the uncaused cause, which turns out to be God.
"Well, but perhaps the lesser things can mutually provide for each other, somewhat as the sides of an arch support each other. In that case, the world of lesser things as a whole (taken as a total system) might be sufficient unto itself. Perhaps the need for a transcendent deity can be eliminated on that basis." The answer is that the comparison is crude and inexact. The ability to act purely spontaneously, in the sense of exercising primary initiative, cannot be built up from the ability to react. To be sure, there are cases in which a whole may be truly said to have attributes that its parts lack, but this is not one of those cases. For here, the total system is a system of reactions and interactions, not something on a higher level. The basic weakness remains in what the system as a whole is and how it works. Alternatively, if the world as a whole were to be on the higher level required, then it would itself have to have the character and status of the First Cause. But this proposal is clearly false, as will be explored further later on.
People imagine that, by making the chain of causes reach back to infinity, they can somehow evade the force of this argument. "The series goes back forever, and so the need for something to start it is eliminated." This objection may be good against some versions of the argument. But Saint Thomas was fully aware of this consideration and found it to be beside the point. For Aquinas argued, specifically and explicitly, that the world could (in principle) have existed forever. In fact, the world began to exist, but that need not have been so. If the world had existed forever, it would still be wholly dependent on God to exist. It would still not have existed of itself. The world would still be created as being made to exist by God. The priority of God over the world of lesser things is a priority of status, of what is original over what is derivative. Indeed, since God is not subject to time, and so is not "in" time, one might well say there is no temporal priority of God to the world.
God is the First Cause as being the primary source of all, apart from any question of standing at the beginning of the series. To say A causes B is to say there is B in virtue of A, so that B depends on A and is derivative from A. One must think in terms of dynamic punch" (or "active energy"), reactivity, and spontaneity, instead of thinking about what follows what in time. (Of course, if it should turn out that the world did begin instead of going back forever, then the point would be all the easier to see. But that would be only an "added extra.")
What makes the point hard to see is that the series of events and the chain of causes do run together in many cases. The answer is to look at a case where they come apart. Once this has been done, the difference between causal dependency and temporal succession can be explored more fully. In principle, this could be done by discussing the issues and questions of simultaneous, or perhaps even retroactive, causation. However, there is a very plain example ready to hand, derived from Saint Thomas.
The processes of generation and reproduction among (human) animals on Earth occur and are repeated through the centuries. There is an obvious way in which the later members of the series are derived from the earlier members. In principle, the series could go back forever. (Whether there could be a "completed infinity" is a serious question in itself, but it is beside the point here.) However, what has to be observed is that the "motive power" for all this comes from the Sun in the sky and not through the series from earlier members to later members. Therefore, there is no need for an original act at the beginning of the series to make the whole thing go. But this is so only because the basis to go is constantly supplied from outside the whole series.
In general, what can reach back forever is the series of events (considered in terms of temporal priority). What cannot reach back forever is the chain of causes (considered as supplying the dependency). Things happen in virtue of the agency that supplies the dependency, even though things happen by means of serial causation. Could there be an infinite regress within the chain of causes? No, of course not. For that kind of regress really would eliminate the original basis that supplies the need or provides for the dependency. This is the point of Saint Thomas's thesis that only an "incidental" ordering among causes, but not an "essential" ordering, can reach back forever. Thus, in the example given, the work of supplying motive power works just the same whether A is the father of B, or B is the father of A. On the other hand, the relation of the beings on Earth to the Sun is not reversible in the same way.
Now, people see that one domino is knocked over by another, which was itself knocked over by another, and so on back. Then, having seen this, they imagine that the series could go back forever. Yes, indeed so, as a series of events, but not as a chain of causes. The domino that does the knocking is merely instrumental relative to the hand that pushed. From the standpoint of the domino that gets knocked, all the others are intermediate between itself and the hand. Being knocked resulted from the original act, and everything else happens in virtue of that act. If the act were removed, nothing would happen, or else things would happen in virtue of nothing. But given that the real world works by dynamic punch, the right answer is that nothing would happen.
What does happen with people's thinking is that they confuse the case where the motive power comes from outside the series (such as the generations of reproduction based on sunshine) with the case where the chain of causes runs through the series (such as the dominoes). Alternatively (or perhaps in addition), they confuse the series of events with the chain of causes. Based on these confusions, they imagine that the chain of causes could go back forever. But this is a serious error that will not stand once the confusions are resolved.
"But why should the two cases be so different? After all, even with the living beings and the Sun, there is an obvious way in which the later are derived from the earlier. Why not here also?" The difference is that the earlier people do not drive the later to act in the same way that the earlier dominoes drive the later dominoes to fall. As Aquinas said, a man begets simply as a man and not as the son of another man. But a domino knocks another, not simply as a domino, but as having been knocked by another domino. The domino that knocks another is itself reacting to being knocked. But the man who begets is not reacting to the earlier series in the same way.
At the present day, there is an exotic application of these points about infinite series versus infinite regress. Stephen Hawking has proposed a tricky gimmick for the structure of time, so that there would be no need for any beginning. Time does not reach back forever, but there is also no point zero. The idea is, with no beginning, there would then be no need for any First Cause.
Now, perhaps time has that structure, or maybe not. But even if it did, that would not help. There would still be causal dependency in the world, and so there would still be the need for some primary basis to support the dependency. This basis would simply have to be outside the whole series, as Aquinas said.
Of course, the idea might be that the process of the world would loop back on itself, swallow its own tail so to speak, and thus be self sustaining. The problem is, this would be an exotic version of having the effect cause the cause. But that is clearly impossible. Once again, there is the series of events, and there is the chain of causes. The series of events might perhaps loop back on itself (as has been proposed), but the chain of causes could not. For then there would be the structure of what is derivative or dependent, but with no primary basis to support it.
(From here, you can still skip to the bibliographic note or the list of linked sites.)
Yet there may still seem to be an objection. For, even at best, what has really been proved? "Even given that there is some First Cause, it does not follow that there is God. For it does not follow either that there is just one such cause, or that this being has the other attributes ordinarily ascribed to God."
The answer to this objection depends on analyzing what is involved in having full spontaneity, free from any conditions or prompting. Everything else can be gotten out of this one basic fact. The way to think of it is that the First Cause has all the autonomy, capabilities, and richness entailed in absolute spontaneity and freedom from conditions. This one point is the whole answer. All the rest is merely the working out of details or the tracing through of implications.
This point can also be viewed from another angle. Where something is the primary basis for things to happen and results to occur within a given realm, that thing will then have total dominion over that realm in virtue of its primacy. This is clear enough where the primacy is within some limited area or context. Where the primacy is unlimited and unrestricted, the basic principle will still apply. In that case, however, the total dominion will extend over all that is or can be. Again, this kind of dominion may be limited or restricted where such primacy is exercised over things that are already given, apart from the action of the primary basis. But, where nothing is already given or presupposed, this basis for limitation and restriction is not present. The prime agent's dominion can then reach across the whole realm of being. (This is very clear at least as regards other things that are subject to being made or produced.) Now, much of what is traditionally ascribed to God is just the formal specification of what this total dominion of God is, how it works, why it exists, and what it entails.
On the other side, there is a very simple way to approach it. Traditional thinkers ascribe various "grandiose things" to God. Now, what (if anything) is the alternative to doing this? If these lofty claims did not apply to God, what then? Would that prospect involve "dragging down" God from the exalted status and character involved in being the First Cause? If so, then that very fact is proof enough that these traditional ideas are true of God after all.
This being cannot depend on anything else or need to receive anything from anything else in order to do what it does. Thus, it exists and has its capabilities of itself, from within itself alone, as well as acting from within itself alone. Again, this being cannot be subject to being made or produced. In fact, it is above and beyond the whole order of arising and perishing, as will become clear. It exists just in virtue of being the very thing that it is. (People speak of this being as “self caused,” and rightly so, but this means simply that it exists through its own nature, or by its own power. It does not mean that this being brings itself into existence from not existing.) Therefore, this being is above being merely contingent in any way, and so it is necessary.
Also, this being is void of passive receptivity as regards its existence, its capabilities, and its activity. Now, this kind of passive receptivity is what Saint Thomas called "passive potency" and what in ordinary English might be called "mere potentiality." The idea of potentiality was developed by Aristotle, and at least strongly foreshadowed by Plato, to answer Parmenides and show why there can be things that are "subject to multiplicity and change." Aquinas took the analysis further and argued that potentiality is the basis for things to be limited or restricted (which is the basis for being subject to multiplicity and change).
Thus, Aquinas said an angel (which is a pure spirit) must receive existence from God, and it is limited on this basis. An angel is made to exist as the kind or species of thing that it is, but then it is limited by this very fact of its own specific nature. Only God rules freely over all kinds. Again, a material being is even more deeply limited, for in addition to receiving existence, its specific character must also be received within matter, just as the shape of the cookie cutter is received by the dough. In these ways, being limited is derived from needing to receive. (Or, more properly, limitation results from receiving according to terms and conditions that impose some restriction.)
So then, the being that is the First Cause, being free from mere potentiality as regards its existence, is thereby free from being limited or restricted as regards its existence. But since the basis for something to exist is the basis for the thing to be what it is, the character of this being is also established apart from any basis of limitation or restriction. It is what Saint Thomas called Pure Act, where the word "act" indicates both actuality and active energy at once. For Aquinas considered that to be actual is something like to be activated (or, as is often said, "actuated") to exist in real life. But the First Cause is actual of itself, as pure active energy. Therefore, this being that is Pure Act (which is the First Cause) turns out to be necessary and infinite.
This result, in turn, has serious consequences, of which the most obvious are that this being is indeed not subject to multiplicity and change. First of all, it follows that this being is above time and change. For there is no basis to develop or receive different attributes at different times. Nor is there any weakness within it whereby it might lapse or fail and change in that way, since it is pure active energy. (Along this line, it cannot perish, nor indeed it can it arise.) Moreover, it is false to say that, since this being is profoundly active, it must be constantly in motion and flux. The activity of this being has to be much more like standing perfectly still instead.
Second, this being is "perfect" as enjoying all the richness of the whole order of being. This is what it is for something to be Pure Act in the sense explained. All the positive "value" that can possibly exist, or that anything can possibly enjoy, must pertain to this being somehow. Of course, how this works must be very different from how lesser beings have what perfection they have. Among lesser beings, having one perfection excludes having another. The being that is the First Cause must have all these perfections in some appropriate (superior) mode.
Third, from the necessity and infinitude of this being, there follows that there is just one such being. (As Plato might say, this being is also not subject to multiplicity.) For there is at most one absolute in any field or system. (To illustrate this point, there is at most one sovereign ruler in a given state.) This point may perhaps be viewed more clearly from the other side. Only where something is less than absolute can there be more than one such thing in a given field or system, for to be absolute is to dominate the whole "region." Again, as William James pointed out, having there be "ultimate pluralism" (instead of having there be just the One Thing, the "block universe,") is more or less the same as having there be things with both limited liabilities and limited powers. Clearly, the being that is Pure Act (which is the First Cause) is the absolute being. Therefore, there is just one such being.
But this way of showing the point is merely suggestive and illustrative. It can also be developed more strictly (which Aquinas did). The questions to ask are, what is involved in having things be numerically separate from each other, what is involved in having things be equal, and what is involved in having things match each other? Insofar as things are truly equal, they match exactly in the respects in which they are equal. Insofar as things match, they do not differ from each other. But when things are numerically separate, they have to be differentiated in some way (as having different attributes, or being at different places, or existing through different times, or whatever). Now, an absolute being has all the fullness of the whole order of being. If something else were separate from it and yet also absolute, it would be equal to it. But then what would differentiate these two (alleged) beings to make them be numerically separate from each other? There is nothing left beyond the whole order of being. So then, the claim that there are two such beings breaks down, and there is at most one.
Fourth, this being is not just one thing among others. Therefore, it is not one more thing in the world. But also, this being is not the world as a whole, nor does it even include the world of things within itself. It must be completely above and beyond the world. Otherwise, if lesser things really belonged to its inner life and character, there would be an impossible situation. For either the finitude and contingency of lesser things would "reach up" into this being (which would destroy it from being what it is), or else this being's necessity and infinitude would "reach down" into the lesser things (which would destroy them from being what they are). Necessity and infinitude on the one side do not mix with contingency and limitation on the other. It is like trying to combine bright light and dark shadows. Again, even if lesser things were to be an "outgrowth" of this being in any way, instead of just having the lesser things "swallowed up" within this being, its necessity and infinitude would still reach down into these things and destroy them.
By the same token, and for the same reason, the absolute being is "simple," not as being "whittled down" or lacking in any way, but only as not being any kind of composite or collective. Unless this were so, there would be the same impossible situation that would exist if the First Cause included the ordinary things of the world within itself. All that belongs to the Pure Act partakes of its necessity and infinitude. But where there is no contingency, there is no possibility (even in principle) of dividing up something, for such division would destroy it (by making it cease to be what it is). So, in the present case, it is false or meaningless to speak of separate elements or principles as making up this being. (It is false or meaningless to speak of "pieces" or "ingredients" where something is deeply unified beyond all possibility of division or of extracting any pieces or ingredients back out again.) Again, where there is no finitude, there is no multiplicity, and so there is no basis for elements or principles to be separate from each other. (Only where the pieces or ingredients are limited can there be more than one of them.) Therefore, there is no composition or collectivity within this being, and so it is "simple."
God is free from all weakness and limitation. Thus, He is free from the weaknesses and limitations involved in containing matter or in displaying material attributes. This is so even though God contains all the positive value of material bodies, for He comprehends this positive value only in some superior mode.
To contain matter is to include potentiality, for that is what matter is. To have size and shape, bodily form and figure, is to be only so much and no more, which is to be limited. Also, it is both to be composite (as having distinct parts) and to include potentiality (as being in principle divisible). But potentiality, composition, and limitation are all contrary to the nature of God. Therefore, this being is spiritual in the sense of being superior to what can fit into matter.
Along this line, God is not dead, inert, or static as though He were lacking or limited. God is overflowing superabundance, and He is this way as His own positive functioning. Again, His functioning is active and energetic, given that He is the First Cause. Moreover, given that God is free of passive receptivity, His functioning is not based on being made to work. Instead, this functioning is from within Himself alone. On that basis, God is living, as Aquinas said. This vital functioning is actively maintained, for that is what it is to have vital functioning as opposed to being passive or inert. But this active maintenance is not as though there were any deadness within God to be overcome. Given His simplicity, there is only vital functioning within Him. Once more, it is perhaps best to think of God as pure active energy.
Yet God is static in the sense of being changeless. But, once again, this is so more as standing still is some sort of positive activity and not as being dead or inert. God is above change as being free from weakness or imperfection. To be static in this way is in fact wholly positive, with nothing negative about it.
There is, then, some one being that is the First Cause and that stands above and beyond the whole world of ordinary things. In addition, this being works by intellect and will. This point follows from its pure spontaneity. Only conscious acts of deliberate choice can even claim to be purely spontaneous. All else is clearly within the realm of "push and pull" causation. This point comes out clearly with the old problem about free choice of the will. Material processes, and most mental processes as well, are clearly within the realm of "push and pull" causation. Even if something were to be deeply and irreducibly random, this would be only a complication within the basic system of such causation. For there would at least be no question with mere randomness of rising above "pushing and pulling" to any higher level. Nothing rises to any higher level, unless conscious acts of deliberate choice do so. (Radioactive decay is problematic in some ways, but it is clearly within the realm of "push and pull" causation, just like any other material process. E. g., atoms must be formed, and then these must be combined into lumps with their various half lives, et cetera. All these things are within the world of "push and pull.")
Here is a shorter way to say it. Given free choice of the will, a person can avoid being "automatic" and display genuine spontaneity. Now, is this based on the working of "nitty gritty" biochemistry? No, of course not. Is it even based on acting out emotions, habits, impulses, and instincts? Again, no, of course not. If such freedom exists at all, it is based on stopping, thinking, deciding on that basis, and then acting on the decision. But all this is exactly what makes up a conscious act of deliberate choice.
But once again, this way of showing the point is merely suggestive and illustrative. What is given is that the First Cause is above all “push and pull” causation. For it is above the whole system of pushing and pulling as being above and beyond the whole system of finite things. Now, what does this fact entail about conscious choice? To approach it from the other side, what exactly is it that “blind” processes lack?
Well, what does it mean to say a process is “blind?” It means that one event follows another apart from any reference to the character or rationale of the process as a whole. Instead of being derived from any consideration of the process as a whole, the process works by natural functioning. Thus, all such processes are “push and pull” only.
The alternative to this is that consideration of the process is the basis. The complete version of this is that this very act of consideration shall also consider itself in relation to the rest of the process. This function of having an act include reflection back on itself is distinctively intellectual. Then again, the function of acting out intellectual understanding is volition. Thus, the First Cause is cognitive and voluntary.
Is the First Cause also morally good, as Saint Thomas believed? Yes, of course it is, and the proof is almost trivial. As Aquinas said, this being enjoys absolute perfection, and so it enjoys full perfection of intellect and will. Therefore, it appreciates and chooses the right order of life. But this is just what it is to be morally good.
This point can also be illustrated from the opposite angle. Can God commit evil? No, of course not. For evil is the failure of what should be. (The classic slogan is that “evil is the privation of due good.”) Thus, as Aquinas said, to commit evil is to fail of some perfection, and so God cannot commit evil.
Yet this assurance might seem to be kind of worthless unless one could also be sure that this goodness is at least strongly analogous to the goodness of finite beings. (Otherwise, to say God is good could be too much like saying God is “I know not what.”) In fact, this too is clearly so. This being enjoys all the value and perfection any being can have, but in a superior mode. The other side of this fact is that finite beings are like lesser versions, inferior copies or reflections, of what the First Cause is. Along this line, the perfection of intellect and will that a finite being can enjoy is like a lesser version of what the First Cause enjoys.
Quite clearly, much remains to be said. Many questions remain. But perhaps enough has been developed to show that these remaining questions about the First Cause will turn out to be in fact questions about God and His relation to creatures.
According to quantum physics, there may be random flickers or bursts within a vacuum. So, perhaps some such flicker or burst is what originally set the process of the world into motion, in which case there is no need for any transcendent deity as the First Cause.
The answer to this proposal, so far from being new, has both the traditional version from the school of Aquinas and also a modern version that has already been developed. The traditional answer is, as has been said, “real metaphysical nothingness is a lot emptier than empty space.” The easy way to see this point is to observe that even empty space is geometrically orderly, and order is a kind of positive something. The modern answer is essentially similar. A vacuum may be a dynamic quantum system, but then it is a positive something by that very fact. For it has its own processes, laws, and attributes. With both versions, to start with a vacuum in empty space is not at all to start from point zero, contrary to what is often imagined.
The processes that run at the quantum level even in a vacuum are just that, processes. They exemplify laws and involve causal functioning. Thus, they involve causal dependency, just like the processes among ordinary objects observable by human subjects. There is then the same need to provide for the dependency, which function must ultimately be traced back to the real First Cause.
In fact, what really comes out of quantum physics is simply that, once a quantum system is set up and activated, it can then produce results through its own functioning. The question of being set up and activated is what is important in this context. From there, the functioning may be random in the sense of being unpredictable even in principle. But this conclusion does not begin to obstruct the Second Way. For this proof is about the basic concern over causal dependency. The question about predictability is a further concern down the line.
In order to make this argument work, one who follows Aquinas needs a very rich notion of cause. Causation is "making to be" in the sense that the cause makes there be the result. Efficient causation is the production of the result, or the activation (or "actuation") from being merely possible or potential into accomplished fact. Thus, the efficient cause is what brings about the result to be effectively realized as actual. Divine creation is then the ultimate version of efficient causation.
Now, this idea is very rich indeed. Some thinkers find it too rich. People have tried to make do with weaker analyses of efficient cause. Indeed, some have even gone so far as to say that there is no "making" of results. There is only the bare fact that things happen according to orderly patterns, with no question of being "made" to do so (whatever that may mean). These challenges turn out to be very hard to answer. Perhaps, in the end, it will turn out to be impossible to make do without the rich notion derived from Aristotle and Saint Thomas Aquinas. But it is extremely difficult to show this to be so, let alone to answer the more sophisticated reasons people have for calling it into question.
In fact, this problem about analyzing efficient cause is part of a cluster or complex of problems. Problems about the analysis of efficient cause, of change and becoming, of what it is for something to be actual, of necessity and contingency, and of what it is for things to have and exercise powers or capabilities are all combined. All these go together into a "package deal." The right answers to these questions are very much issues of ongoing philosophical debate.
Here is the short way to say it. There is the analysis of the basic nature and structure of reality that Saint Thomas took over from his predecessors and developed further. Given this analysis, one must certainly reach the same conclusion and affirm God. But whether this analysis is right is perhaps the great question of philosophy.
(Only works available online to be read are noted here.)
The basic argument is developed in his Summa Theologica (pt. 1, qu. 2, art. 3), but also in the Summa Contra Gentiles (bk. 1, ch. 13, par. 33). Elsewhere in the Summa Theologica is the argument that the world could have existed forever, although it did not in fact and would still have been created by God even if it had (pt. 1, qu. 46, art. 2). His underlying analysis of what it is to be actual pops up in many places, but the first natural and obvious place to look is in the treatise On Being and Essence. (Chapters 4 and 5 of this treatise are especially relevant to the present topics, although they are even more relevant to the Third Way.)
et al.: Readings for Philosophers and Catholics
From the Jacques Maritain Center at the University of Notre Dame, this collection is less than a full library but has a rich supply (in hypertext). First and foremost, there is the Summa Contra Gentiles. There are also several relevant articles from the old 1917 Catholic Encyclopedia. There are also many other items, as well as links.
Thomas Aquinas's Works in English
From this religious community of Dominican friars (which is what Aquinas was) comes this rich load of texts.
This library includes many goods (in plain text or zip). There is the Summa Theologica, split up into large chunks. One of these chunks includes the proof with the Five Ways (Questions 1-36 of the First Part). Also among the documents in their library, there is a very brief statement of the argument ("PROBLEMS OF THE FIRST CAUSE" by Fr. William Most). For its length, this document is a remarkably good elementary introduction.
From the Department of the Classics at Tufts University, here is a great load of goods (with both Greek and Latin authors and resources for them), including Plato and Aristotle.
From Paul Halsall (doctoral graduate and former Web designer in the History department of Fordham University) comes this page. There are links to sources onsite, to external sources, to other sourcebooks on the site, and to a help page. This sourcebook is reasonably well indexed, with links to important sections and supplements. There are two pages in the folder that are chiefly relevant here. One is entitled "end of the classical world" (for some of Aquinas's early predecessors). The other page is entitled "intellectual life" (for the later times, beginning in the ninth century).
From this University Professor at Georgetown University comes this load of texts from, and essays on, late antiquity, including Augustine and Boethius. These can be valuable for understanding the history behind Aquinas. (Augustine's Confessions may be a good place for a novice to begin picking up background.)
From the Yale Lectures of Gyula Kilma at Fordham University, this piece treats the Second and Third Ways together, as well as Anselm and natural theology in general. It is very good for gaining theoretical understanding, but it is clearly advanced.
Theism: Lecture Notes
From Robert Koons of the University of Texas at Austin, this is a rich load of material. There are some points to criticize, but on the whole, this site is truly worthy. Professor Koons shows the overlap of the Second Way with the First and especially the Third. But then, they do overlap in fact. Some of the notes are directed to other concerns, and some of the notes are directed to more advanced or technical concerns. But three are very good for more or less elementary reading (although not for complete novices) and will be cited separately here.
Notes and Handouts from Alfred J. Freddoso at the University of
This list has many valuable items. Three will be separately noted here.
A sketchy outline only, but still useful, from Ancient and Medieval Philosophy (somewhat advanced).
Another sketchy outline, from Introduction to Philosophy (slightly milder).
on St. Thomas Aquinas, Summa Contra Gentiles I
A more extended (and not too advanced) treatment, from Philosophical Reflections on Christian Belief.
(This one is good for the basic concepts and apparatus, as well as further consequences, but it skimps on the central argument.)
Thomas Aquinas: "The Dumb Ox"
In this work, G. K. Chesterton displayed the gift for turning heavy content into light reading. This literary biography has been recognized as a serious contribution. It is a good elementary introduction to Saint Thomas's thought as well as his life. This work is especially good for a novice who is really starting from point zero. This posting is plain text, but an html version is also available at this site. **There is one point some modern readers may find hard. Some of Chesterton's remarks about other cultures and other religions may be very regrettable. But even in the worst case, these stereotypes should be taken only as showing the truth about Saint Thomas by way of contrast. Whether his views of the other cultures and religions are truly fair to those people should be left aside in this context.**
to the Summa
Like Aquinas before him, Father Farrell was a Dominican. His Companion is perhaps a little soft on some points, but it is a fairly decent semipopular presentation. In particular, chapter 2 of the first volume develops all five ways, including the second, and goes into the underlying concepts and apparatus. Subsequent chapters develop further consequences of the basic argument.
First Cause Argument
From Peter Kreeft comes this brief statement, which treats the First, Third, and Fourth Ways as well as the Second. It is very good on the question of why an infinite regress will not work.
on Scotus on Causal Series
From Edward Feser comes this explanation of why there has to be a first cause, which turns out to be the (Divine) First Cause, and why the attempt to make do with an infinite series and no First Cause ends up with a vicious infinite regress. Like both Kreeft and the present author, Feser points out that what is needed is something primary to support the dependencies among things in the world, not necessarily a first member of the series.
Defense of the Cosmological Argument
This statement of the argument has become something of a modern classic. (The present author is also indebted to this essay.) It is chiefly concerned with the Third Way, but there is enough spillover onto the Second Way to make it well worth including. (This piece is in pdf.)
Even someone who is opposed to the religion Saint Thomas followed might still travel the Second Way, purely on the strength of the philosophical argument. The proof is, Rousseau did just that. This article explores the version of the proof Rousseau developed.
Vacuum Versus Real Metaphysical Nothingness
This article explores a careful statement of the answer to this concern, chiefly the modern answer, but traditional ideas are also discussed. This article is itself a commentary on this book review. Apart from both of these things, there is also this piece here, which discusses quantum functioning along with other concerns about creation and modern physics.
From Joseph Magee (doctoral graduate of, and former Webmaster at, the Center for Thomistic Studies) comes this rich load of essays and commentaries, as well as texts and links. The going here is perhaps slightly stiff for beginners, yet it may be reasonably mild (at least relative to what can be expected, given the inherent difficulty of the topics and the limitations of postings on the Internet). Someone with one or two courses in philosophy might well try it. The essays and commentaries are good enough to justify some measure of having to crack one's brains. This site is truly worthy.
the Principles of Nature
This work was translated by the late Gerard Campbell, formerly Professor at St. Jerome's University. In this work, Aquinas analyzes the processes of change and of coming to be, including the four types of causation that he takes over from Aristotle. But it is not for beginners.
Logic and Philosophy
(There is also a No Frames Version available.)
From Paul Vincent Spade of Indiana University, this offering has items to download and a list of people with email addresses (and sometimes homepages), as well as various links.
Labyrinth: Resources for Medieval Studies
From Georgetown University comes this Web folder full of linked lists to delight medievalists.
Completed 04/22/1999 by David McGraw
Revised Version (Not Posted) 07/07/2002
Further Revised 04/02/2007
External Links Only Updated 04/23/2011
Revised and Expanded 08/10/2013
Further Revised and Expanded 01/03/2015
Technical Corrections of Underlying HTML Source Code 01/13/2015, 01/19/2015, 08/03/2015, and 09/05/2015
Introductory Essay Expanded 10/04/2015
External Links Only Revised and Expanded 02/04/2016, 02/05/2016, and 02/07/2016
Introductory Essay Revised and Expanded 01/11 & 12/2017 and 06/12/2017
External Links Only Updated 08/08/2017
Revised and Updated 08/04/2019 and 08/14/2019
Copyright © 1999, 2002, 2007, 2011, 2013, 2015, 2016, 2017, 2019 David McGraw
The author is solely responsible for the content of this page.
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