# Infinite series of cause and effect **URL:** \ **Category:** Factual Questions\ **Created:** [March 22, 2015, 11:03pm UTC](https://boards.straightdope.com/t/infinite-series-of-cause-and-effect/715720 "2015-03-22T23:03:17Z")\ **Posts on this page:** 11\ **Page:** 1
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [March 22, 2015, 11:03pm UTC](https://boards.straightdope.com/t/infinite-series-of-cause-and-effect/715720/1 "2015-03-22T23:03:17Z")
I’ve always heard that it’s not possible to have an infinite progression (or regression) of cause and effect. This is usually part of the “First Cause” or “Prime Mover” argument for the existence of God. But why is an infinite series of cause and effect impossible? Since this argument preceded knowledge of the Big Bang, assume that there wasn’t one. Bonus question: If there had to be a First Cause, will there have to be a Final Effect? ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [March 22, 2015, 11:18pm UTC](https://boards.straightdope.com/t/infinite-series-of-cause-and-effect/715720/2 "2015-03-22T23:18:47Z")
There are infinite series that converge. If each step took half the time of the previous step, then it would only last a finite time. But that’s implausible, and not what is normally meant in non-mathematical circles by an infinite progression. For most infinite series, something happens, then something happens, then something happens … implies that you never get to the last something happening. Infinity is not a very large number; it means never-ending. Therefore you can’t get to the last step, or, conversely, work backwards to a first step. There are always an infinite number of steps yet to go. ---
**Author:** ![panache45](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/panache45/32/64_2.png) [@panache45](https://boards.straightdope.com/u/panache45)\ **Post date:** [March 22, 2015, 11:27pm UTC](https://boards.straightdope.com/t/infinite-series-of-cause-and-effect/715720/3 "2015-03-22T23:27:11Z")
Of course. So why do some people say that an infinite cause and effect is impossible? ---
**Author:** ![Thudlow\_Boink](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/thudlow_boink/32/320_2.png) [@Thudlow\_Boink](https://boards.straightdope.com/u/Thudlow_Boink)\ **Post date:** [March 23, 2015, 12:19am UTC](https://boards.straightdope.com/t/infinite-series-of-cause-and-effect/715720/4 "2015-03-23T00:19:34Z")
I assume you’re referring to something like [this](http://www.existence-of-god.com/first-cause-argument.html)? (which is one of the first things that came up when I googled “first cause argument”) Especially the section on “It’s Impossible to Traverse an Infinite Series”? I can maybe sorta kinda see the psychological appeal of the argument they’re trying to make (how can it be “turtles all the way down”?), but I don’t really think it holds up: too much question-begging and/or false analogy. (If we are considering the “first cause” argument, I prefer some of the other sites that came up when I googled, such as the articles at [Wikipedia](http://en.wikipedia.org/wiki/Cosmological_argument) or [RationalWiki](http://rationalwiki.org/wiki/Argument_from_first_cause).) ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [March 23, 2015, 12:33am UTC](https://boards.straightdope.com/t/infinite-series-of-cause-and-effect/715720/5 "2015-03-23T00:33:58Z")
> [@panache45](#): > > Of course. So why do some people say that an infinite cause and effect is impossible? Because it can’t happen? I don’t get this response to my response. Could you rephrase? ---
**Author:** ![Asympotically\_fat](https://avatars.discourse-cdn.com/v4/letter/a/e47c2d/32.png) [@Asympotically\_fat](https://boards.straightdope.com/u/Asympotically_fat)\ **Post date:** [March 23, 2015, 1:35am UTC](https://boards.straightdope.com/t/infinite-series-of-cause-and-effect/715720/6 "2015-03-23T01:35:53Z")
If you have a causal chain A-\>B-\>C, you can always add a preceding event to get a longer chain D-\>A-\>B-\>C (though possibly causal chain are limited to 26 events) and there is nothing contradictory about a causal chain …-\>A-\>B-\>C-\>… with no beginning and end. In general relativity the causality is much more nuanced and instead of casual chains we talk about causal curves. In big bang theory all causal curves can only be extended a finite amount of time back in the past. This is however due to the particular physics of the situation rather than a deep underlying theoretical reason in general relativity and casual curves that extend arbitrarily far back are both theoretically allowed and physically reasonable. One thing I will say though is that the Universe tends to evolve towards the highest entropy state, so given an infinite amount of time you would expect to find us in that state, but we are not. So this is evidence (though not conclusive evidence) that the Universe, at least as we know it, has existed for a finite amount of time. ---
**Author:** ![Exapno\_Mapcase](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/exapno_mapcase/32/1051_2.png) [@Exapno\_Mapcase](https://boards.straightdope.com/u/Exapno_Mapcase)\ **Post date:** [March 23, 2015, 2:31am UTC](https://boards.straightdope.com/t/infinite-series-of-cause-and-effect/715720/7 "2015-03-23T02:31:51Z")
My understanding of First Cause apologists is that they spend no time whatsoever on the nuances of relativity or, in fact, on any mathematical sophistication at all. Everything is an elaboration of: infinity is impossible, therefore God. All three of Thudlow Boink’s cites confirm this. ---
**Author:** ![naita](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/naita/32/5862_2.png) [@naita](https://boards.straightdope.com/u/naita)\ **Post date:** [March 23, 2015, 8:51am UTC](https://boards.straightdope.com/t/infinite-series-of-cause-and-effect/715720/8 "2015-03-23T08:51:15Z")
> [@panache45](#): > > I’ve always heard that it’s not possible to have an infinite progression (or regression) of cause and effect. This is usually part of the “First Cause” or “Prime Mover” argument for the existence of God. But why is an infinite series of cause and effect impossible? > > Since this argument preceded knowledge of the Big Bang, assume that there wasn’t one. > > Bonus question: If there had to be a First Cause, will there have to be a Final Effect? It’s an attempt to cloak something emotional in a dress of logic. Time extending backwards for infinity is incomprehensible, incomprehensible is not acceptable -\> god. ---
**Author:** ![LSLGuy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lslguy/32/5813_2.png) [@LSLGuy](https://boards.straightdope.com/u/LSLGuy)\ **Post date:** [March 23, 2015, 9:20am UTC](https://boards.straightdope.com/t/infinite-series-of-cause-and-effect/715720/9 "2015-03-23T09:20:09Z")
> [@naita](#): > > It’s an attempt to cloak something emotional in a dress of logic. Time extending backwards for infinity is incomprehensible, incomprehensible is not acceptable -\> god. Just for clarity … Time extending backwards for infinity is incomprehensible _to some people of limited imagination_, incomprehensible is not acceptable _to some people of limited imagination_-\> god _for some people of limited imagination_. ---
**Author:** ![Mijin](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mijin/32/9369_2.png) [@Mijin](https://boards.straightdope.com/u/Mijin)\ **Post date:** [March 23, 2015, 10:06am UTC](https://boards.straightdope.com/t/infinite-series-of-cause-and-effect/715720/10 "2015-03-23T10:06:20Z")
There isn’t anything logically impossible about an infinite chain of cause and effect as far as we know. And indeed most variants of the prime mover argument I’ve come across don’t say it’s impossible, just say we know there was a start point: the big bang. Of course, I’m not advocating for the prime mover argument. It’s a completely empty argument as it purports to give us some reason for supposing the existence of a god, but in actuality, fails to do so (it just asserts that the first event, or the event that happened “outside of time” or whatever, _just must be_ supernatural). ---
**Author:** ![Saint\_Cad](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/saint_cad/32/18907_2.png) [@Saint\_Cad](https://boards.straightdope.com/u/Saint_Cad)\ **Post date:** [March 23, 2015, 4:03pm UTC](https://boards.straightdope.com/t/infinite-series-of-cause-and-effect/715720/11 "2015-03-23T16:03:00Z")
The standard for this is Thomas Aquinas > [@](#): > > The second way is from the nature of the efficient cause. In the world of sense we find there is an order of efficient causes. There is no case known (neither is it, indeed, possible) in which a thing is found to be the efficient cause of itself; for so it would be prior to itself, which is impossible. _Now in efficient causes it is not possible to go on to infinity, because in all efficient causes following in order, the first is the cause of the intermediate cause, and the intermediate is the cause of the ultimate cause, whether the intermediate cause be several, or only one._ Now to take away the cause is to take away the effect. Therefore, if there be no first cause among efficient causes, there will be no ultimate, nor any intermediate cause. But if in efficient causes it is possible to go on to infinity, there will be no first efficient cause, neither will there be an ultimate effect, nor any intermediate efficient causes; all of which is plainly false. Therefore it is necessary to admit a first efficient cause, to which everyone gives the name of God. I think this demonstrates the inherent circularity of the argument. There cannot be an infinite number of causes because (obviously) there has to be a first one. Therefore since there was a first one, there can’t be an infinite number of causes.