Thomas’ Second Way

Bob LaRocca leads a discuss on Thomas Aquinas’ Second Way. The Second Way is an argument for the existence of God from efficient causes. The flow of the argument is as follows:

  1. We perceive a series of efficient causes of things in the world.
  2. Nothing exists prior to itself.
  3. Therefore nothing is the efficient cause of itself.
  4. If a previous efficient cause does not exist, neither does the thing that results.
  5. Therefore if the first thing in a series does not exist, nothing in the series exists.
  6. The series of efficient causes cannot extend ad infinitum into the past, for then there would be no things existing now.
  7. Therefore it is necessary to admit a first efficient cause, to which everyone gives the name of God.

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Philosophy for Theologians aims to look critically at the problems of philosophy by considering everything in light of God's revelation. The program not only wants to address philosophical questions but also to equip you with a way to think about these questions. Browse more episodes from this program or subscribe to the podcast feed.

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Steve Ruble

9 years ago

Hi guys,

Interesting show, although I think there are probably more interesting things you could be spending your PfT time on. I’d love to hear you discuss Plantinga’s epistemology, say, or metaphysical naturalism – something that’s currently in play in the philosophical arena, rather than the dustier stuff you usually focus on.

Anyway, the only real critique I have of the show is – as is so frequently the case – that you ought to read critiques of the positions you put forward before you spend time presenting them. Craig’s confusion about the feasibility of an “actual infinite” are something I learned about in my sophomore year. You might as plausibly put forward Zeno’s arrow as an argument for why motion must be an illusion. In both cases, the “paradoxes” are well understood by philosophers and mathematicians to be the result of trying to think about infinity as if it were not infinite and being boggled by the result.

Likewise, with regard to M-theory and the Hawking quote that everyone has been going on about – don’t you think it’s possible that Hawking’s argument and proof of his position is beyond your ability to critique? I invite you to check out the M-theory page on Wikipedia – please let me know how far you get down the page before you’ve encountered at least 5 concepts you don’t understand. (I didn’t get past the introduction). Isn’t it rather ludicrous, then, for you to expect that you could explain it away with some metaphysical handwaving? If M-theory were the correct explanation for the origin of the universe, how would you be able to tell?

Compare, then, Hawking et al.’s incomprehensible (to non-experts) theorizing with your comprehensible assertions that you are right because you are really sure that you’re right. Which one would you say, objectively, is more likely to be correct? Just going on what you know about how humans behave, think, and act, is it more likely that Hawking et al. know more about the origin of the universe than you, or that your assertions are the Truth Of All Creation? Based on the entire history of science, during which the scientists have consistently, every time, been more right about the nature of the universe than the religionists with their revealed truths, I’m going to go with Hawking on this one.

In closing – “There are no atheists, there are just arguments about the nature of God,” has got to be one of the silliest quotes I’ve heard on this show (that wasn’t from Van Til). I once argued with a woman in a bar who asked me, “You believe in life, and love, and the universe, right?” When I responded that I did believe in those things she said, “Well, you know, those are just other words for God. I knew you were a believer!” Somehow I’ve come to expect this show to hold itself to a slightly higher standard than that.


9 years ago

I hear ya on one level. The work and brilliant mind of Hawking can’t and shouldn’t be dismissed. On the other hand, cosmological complexity doesn’t prevent discussion of the philosophical principles it both borrows from and depends on. I can’t comment on how neutrinos interact with black holes and the physics behind it, but when anyone speculates on the origin of the universe and the mechanics of its beginning from incomplete data observation, they’re on philosophical and theological turf. And for what it’s worth, no one here makes the argument that we’re right because we’re really sure we’re right. You know that. As far as Hawking goes as an authority, let’s see how that plays out. Because he has recently changed his mind, or modified it. Do you think the origin question is now settled in the scientific community? There won’t be significant changes in the next 100 years? 200 years? If around, would you then just form in line with that scientific consensus, waiting until the next modification or shift? I’m all about learning from science, but only as it is formed and not in contrast to what God has communicated, foundationally including his presence and act of creation.

The Wiki article was really interesting. The systems remind me a little of T, S4 and S5 modal logic systems, although I’m sure string theory is exponentially more complicated. You might find this UK review of Hawking interesting: http://www.economist.com/node/16990802

Steve Ruble

9 years ago

That review is interesting, although I’m sure that if I read the book I’d have a slightly different interpretation of the claims the reviewer mocks. I agree with Hawking and Mlodinow (as he portrays them) that it’s the province of science, not philosophy, to answer those “why” questions – if you’re looking for causal answers. If you’re looking for or expecting teleological answers then, of course, science won’t give you any. I’m guessing that’s what you mean when you refer to “philosophical and theological turf”… the idea that you can, by thinking about it, derive purposes and meanings which others should be convinced of. Of course, when you take that route, you have to hope that no one will realize that you actually have no more authority in your pronouncements about the “meaning of life” than has anyone else.

I’m afraid I don’t see the distinction between thinking that you’re right because you’re really sure you’re right, on the one hand, and thinking you’re right because you’ve assumed in advance of any reasoning that you’re right, on the other. Especially when the latter is accompanied by the assertion that no evidence yet to be encountered can or should sway one’s original assumptions. To me, those two paths look pretty much the same, and I would expect the walkers on either path to quickly fall into the ditch. Of course, they might not notice…

Of course, Hawking isn’t talking to you True Believers – he’s talking to those who might be deceived by arguments like Craig’s; arguments based on metaphysical constructs without any necessary connection to the real world. It’s no use saying that every effect must have a cause when we know perfectly well that some effects have no cause – Hawking radiation and radioactive decay, for example. It’s pointless to ask why the universe began if it’s in the nature of the universe to begin – and that’s the sort of explanation you should be totally comfortable with, given your predilections for “natures” and “essences” of “beings”.


9 years ago

With regard to you suggestion that “it’s in the nature of the universe to begin” you might consult Edward Feser’s recent discussion on self-causation (http://edwardfeser.blogspot.com/2010/12/dreaded-causa-sui.html). If by “begin” you mean “to be” or “to exist” then your position suggests that the absolute ontologically sufficient reason for the universe is the universe itself. Did the universe have a “nature” before it began to be? If not, is the universe’s actual instantiation of a “nature” (I use “nature” loosely here) in time an instance of the future causing the past? Aquinas would argue that it is not in the nature of the universe qua universe to begin in time (though as a Christian he believed it did begin in time), but it is in its nature to be caused to be inasmuch as its existence and essence are not strictly identical. Nothing that is not absolutely simple in an existential sense can be the final ontological reason for itself. So, yes, there is a point to asking “why” the universe began or exists at all. Anyhow, I think you will find Feser’s discussion thought-provoking.

Cape Town Property

9 years ago

~William Shakespeare, Sonnets to Sundry Notes of Music, IV

"Philosophy for Theologians" on Aquinas and Other Topics | The Partially Examined Life Philosophy Podcast | A Philosophy Podcast and Blog

8 years ago

[…] On Thomas’s “First Way.” On Thomas’s “Second Way.” […]

A Thomist

6 years ago

Your summary of the second way is incorrect. Premise 6 is not part of Thomas’s construction of the argument. You seem to be conflating the second way with Craig’s Kalaam argument, which is an intrinsically different argument from what is found in the second way. Thomas does not include a time element to the argument since he thinks that an actual temporal infinite is possible. Thomas is referring to a causal hierarchy or essentially ordered causes rather than the accidentally ordered causes of linear temporal development.

In any case, this show is mislabeled – it is not actually about Thomas’s second way.



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