The Fifth Way: Argument from Design

non sequitur ?

Not really. I’m saying that if you could reach a conclusion from one statement you shouldn’t be able to claim that you could reach the same conclusion from a contradictory statement.

I don’t think that God is dependent upon the specific freezing point of water, therefore the conclusion is worthless.

It’s the argument against the proposal in the op in a nutshell.

We know the arrow hit the target. So, is the argument against design more cogent than the argument from design? If the arrow (human being) is not a directed end then that end is a chance event through random mutations and natural selection.

First, the probability of random mutation and natural selection as an explanation for human beings evolving from rocks is extremely low. Seeing the math, evolution proponents, sounding like Lloyd from “Dumb and Dumber”, chant, “So you’re telling me there’s a chance?” Or they beg the question with the circular argument, “We exist, someone won the lottery, so that proves evolution.”

Second, the evolution theory must violate at least 4 self-evident first principles:

  • The principle of sufficient reason: the existence of being is accountable either in itself or in another.
  • The principle of proportionate causality : the effect cannot be greater than the cause.
  • The principle of resemblance : every agent produces a thing that is in some degree like its own form.
  • The principle of operation: each thing acts according to its own form.

Teilhard failed in his attempt to square evolution theory with metaphysical first principle of sufficient reason and proportionate causality by simply assigning to rocks the potential to become man. His effort fails the latter two principles and must be rejected.

You’re focusing too much on the word purpose. A weak teleology is basically just the scientific principle that if you put the same thing under the same conditions you’re going to see the same results and tendencies. We go one additional step in that these tendencies towards these ends is due to the nature of the entity (or system). In the rain cycle we are simply looking at the circular tendency of evaporation to rainfall.

And as far as living organisms are concerned, evolution didn’t just blow Paley’s arguments out of the water, it also contradicts the idea of teleology in nature. The ‘purpose’ of an oak tree (and ‘purpose’ most definitely needs the scare quotes) is…to make another oak tree. And an acorn is part of that process. I don’t see anything deep and mysterious about it. I see no need for an ID’er to ensure the process continues in the right direction.

I could not care less about Paley. Paley’s arguments are neither here nor there with regards to the Fifth Way.

As for you not seeing anything “deep and mysterious” about living things having ends or tendencies towards reproduction and flourishing? Good. It’s not supposed to be deep or mysterious. That things living and not have natural tendencies is supposed to be a pretty much self-evident fact of nature once you’ve had any experience with reality. That actually lends itself to St. Thomas’ points that things do naturally tend towards these ends (as opposed to the effect having no relation to its cause). This type of teleology is self-evident. What is not self-evident is that there being any such tendencies at all is evidence for God. Hence why the purpose of the Fifth Way is to move by reason from the self-evident principle to the conclusion that God exists.


This smacks of the typical arguments I see used against Paley, which misunderstands St. Thomas’ point. An electron doesn’t at one time move away from positive charge and then move towards a positive charge (barring other forces at work). Hitting an electron with a photon does not cause it to emit a sound like an elephant. The electron tends towards the same results under the same circumstances. What the specific result is doesn’t matter, what matters for any given thing is that it has consistent natural tendencies instead of the effects being absolutely random.

Did you not read what I wrote above regarding what’s meant by chance?

Wesrock: I agree it’s not by chance that natures have these properties, but that’s what the argument is showing and not what I think St. Thomas means in that quoted instance. In that instance, I think St. Thomas means that what limited things an entity does is determined by its nature, that it has a limited range of specific things it does rather than things just being random. Water freezes at 0 degrees Celsius. It doesn’t randomly turn into a bouquet of flowers or burst into flames. It does the same thing (under the same conditions). When it gets to 0 degrees what happens isn’t a roll of the dice. We can apply this even knowing that quantum indeterminacy is a thing. Even if we can’t predict with 100% accuracy, there’s a range of things within its nature we can see are possible. It’s not a coin toss whether an electron has a certain charge and behavior within magnetic fields instead of growing into a dog.

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It’s not that “it was designed that way”. Stop bringing Paley into this. Things of Type A tend towards Y. Things of Type B tend towards Z. It’s not about being amazed that A tends towards Y instead of towards X or Z. It’s that A has a tendency or such consistency at all. It’s not mysterious. It’s just the point and the premise.

The same causes tend to produce the same effects rather than absolutely random effects. The same substances (or entities) tend towards the same ends instead those tendencies at any given moment being random.

Again, it’s not the specific end that matters and being surprised it’s this end instead of that end particularly. It’s simply that the above two sentences are true in a general sense. It’s such a basic affirmation that I’m both dumbfounded that people miss it but also kind of understand that everyone thinks it has to be something deeper and so skips over it.

At the moment, all I’ve discussed so far is the first proposition. I don’t think most people would take issue with the second proposition. If I have the opportunity later I would like to try discussing the third. The third is the one that does the “work”.

Not sure because first of all there is always some uncertainty in the initial cause. Over the short run, this uncertainty is not noticed, but over the long run of millions of years you may notice different results as we see in the evolution of life into different species.
Secondly, take the same roulette wheel and the same ball. This same roulette wheel and this same ball will tend toward giving different results so that in some cases you will win on red, whereas in other cases you lose. Similarly with a slot machine.

Take the roulette wheel. There are some who would say that if every exact mechanical part of the roulette wheel, the weight distribution of the ball and its initial momentum, the exact distribution of air, and all such things were kept exactly the same and ensured to have absolutely no variation from previous experiments, the result would be the same.

Even if there is some indeterminacy the roulette wheel will behave in the same general way, insofar as it will physically will spin and repeatedly transfer momentum to and from the ball until the ball either lands on red or black somewhere on the board, or the ball is thrown off the board altogether. That you can attempt any physical model of physical interactions at all underscores the point. The roulette wheel doesn’t transmute the ball into a pigeon, or cause it to disappear, and if the circumstances are the same as previous experiments the ball isn’t going to change color or melt instead of just bouncing around when put into a roulette wheel.

Organisms are under selective pressures by which they either go instinct or become more competitive in a niche. It’s not that the pressures or biology is pointed towards creating this specific organism or that specific organism, as the confluence of many different events creates chance. It’s that the causal factors of these different contributors proceed in a regular fashion.

What you’re basically trying to reject is the idea that a cause has any determination (or even relation) to its effect or vice versa. That I can’t model any systems because that presupposes predictive behavior. That I can’t know whether one billiard ball striking another on a pool table will actually cause a transfer of momentum between the balls or a bunny to appear, even if a similar set of conditions has resulted in a transfer of momentum once or twice or a million times. And if a bunny did appear, we would assume it was due to that there was something very different about what actually occurred that resulted in the different effect.

It is that there is any regularity at all that is important to St. Thomas.

What i am claiming is that there is always some small uncertainty in the original cause. There is an overriding cause which we know, but there is always an infinitesimally smaller epsilon cause added on (i.e., we have C + epsilon, not just C). Epsilon generally will not affect anything so that the effect will remain “basically” the same. However, even the effect has a small uncertainty. In the short run, these uncertainties will not be noticed. However, over longer time periods these uncertainties will come into play so that the results will differ.

But according to the uncertainty principles you cannot know with exactness both the momentum and position simultaneously.

Stating that effects can be interfered with by other causes doesn’t undermine the point. It’s exactly what you’d expect. St. Thomas was actually very much aware of the fact that if A tends to B then it means that B will mostly obtain unless other secondary causes prevented it from occurring.

Stating that a roulette wheel (perhaps) might slowly get dinged up and damaged over time or that on one spin you might have a stronger wind than on a previous spin and that these types of things could change the results misses the point. I don’t want to get too bogged down in differentiating between substances and accidental form, either (of which the roulette wheel is the latter), but in terms of the substances the wheel is made of and the regularities we expect from a roulette wheel we’re looking at things impacting each other and the transfer of momentum in such cases as being regularities of the materials involved.

The intent of science is to figure out what effects things produce under certain circumstances. Circumstances are controlled in experiments precisely (to the best of the scientist’s ability) to determine what effects are due to the substance alone apart from other causes (which also behave with regularities). If we did not expect to find tendencies then science and its ability to predict things would be bunk.

I’d like to get into this with more depth when I approach the third proposition. I’ve started on a response but am still near the beginning.

I think i might be interpreting the fifth way differently (not necessarily as Aquinas intended). But even if we assert that the first premise is wrong if it infers or asserts a teleology, i think the argument can still work without mention of a teleology. So lets keep it simple. Here is a restatement of the argument as i understand it.

1. There are laws of physics. Things have a regularity and direction in their activity. Particular things have a tendency towards particular effects. This is not by chance that natures produce effects according to their natures insomuch as they do not randomly produce any number of effects. For example a goat doesn’t randomly transform into a dining room table.

2. Natural activity is blind to any end. It lacks knowledge and understanding. So we need to explain why natures have laws of behaviour, why there is regularity in their behaviour since they do not intelligently move to any possible end.

3. But as an arrow reaches its target because it is directed by an archer, what lacks intelligence achieves goals by being directed by something intelligent.

4. Therefore some intelligent being exists by whom all natural things are directed to their end; and this being we call God.

Now the obvious rebuttal to this is simply to assert that the laws of physics is existentially-necessary. But for sake of argument Aquinas has already established in the first 3 ways that physical reality is not necessary and therefore the laws of physics is not natural. Therefore the fact that things move to particular ends and produce particular effects and have regularity in their behaviour, can only be explained by an intelligent cause.

So, i would argue that the fifth way taken by itself suffers some difficulty, but taken together with the other ways i find that the fifth way succeeds.

Well, to quote St. Thomas directly.

We see that things which lack intelligence, such as natural bodies, act for an end, and this is evident from their acting always, or nearly always, in the same way, so as to obtain the best result.

He has not structured the Fifth Way as a formal syllogism in the Summa the way @IWantGod did in the first post. But if I can snip St. Thomas’ words a little to better fit the start of a syllogism:

  • We see that things which lack intelligence, such as natural bodies act always, or nearly always, in the same way, so as to obtain the best result.

Or to break it apart further.

  • We see that there are things that lack intelligence.

  • We see that there are things that act always, or nearly always, in the same way, so as to obtain the best result.

Best is a problematic word nowadays, as “who judges best!?” St. Thomas just means a thing will better obtain what a thing naturally tends towards the fewer the interfering causes are.


It’s not that water froze at a certain temperature that Aquinas or i find significant. It is the fact that water always freezes at a particular temperature. It is the fact that there are regularities that needs to be explained.

The problem with effects following perfectly from given causes is that we have free will. If all our actions and choices are determined by pre-existing causes, would that not mean that there is no free will?

And just to head off certain types of objections, we realize that the freezing temperature of water is dependent also on other factors such as air pressure, “impurities” in the water, etc… But even when accounting for these other circumstances there is a regularity.

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Let’s not get sidetracked in this topic regarding the Fifth Way. At least not until after we beat the topic to death.

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But this is not a sidetrack since it concerns what is meant by cause and effect and if these causes and effects really are what people think they are. Not every effect has a pre-existing cause. Otherwise, why should you lock up a man who just killed his neighbor in an argument over a barking dog? There were pre-existing causes which determined his tendency to act that way and since these causes were pre-existing, they were beyond his control and his responsibility. He did not have a free choice because it was the Devil, i.e., the pre-existing causes, that made him do it. All his actions are determined by pre-existing causes over which he has no control.

Well, it’s not by chance that a ball roles down a hill. It will always happen so long as there is gravity and all the right conditions are met. Also, effects do not randomly follow their cause. What is mean’t by this is that particular natures tend to produce particular effects. A cow will not randomly transform into a cat or a mountain for example. Effects tend to consistently occur according to the nature of their cause and not by chance.

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Aside from the whole broader discussion of the difference between transient and imminent causality and that the reality (or lack thereof) of free will has no impact on whether the Fifth Way follows, the Fifth Way concerns the acting of entities lacking intelligence. The acting of intelligent agents, then, is not in its scope. Perhaps we can make a broader argument, but it’s not necessary here and goes beyond what’s stated in the Summa as “the fifth way…”

Please see the quotation from the Summa in post 32: The Fifth Way: Argument from Design

So again, let’s not get sidetracked.

Unfortunately, there are reasons to believe that not all natural bodies work toward some goal, and even if they did, the end could come about by chance. It has not been proven that there is always a pre-determined end to which natural bodies are working. BTW, are humans considered to be natural bodies or are they unnatural in some sense?

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