
Principle of Sufficient Reason - lainon
https://plato.stanford.edu/entries/sufficient-reason/
======
justinpombrio
Take three principles:

 _The Principle of Sufficient Reason:_

    
    
        Every fact can be explained in terms of some other facts.
        Call those other facts the sufficient reasons for said fact.
    

_The Principle of Non-Cyclic Reasoning:_

    
    
        No fact is ever explained in terms of itself. That is,
        if you repeatedly take the "sufficient reasons" for a fact,
        you never get back to the original fact.
    

_The Principle of No Infinite Regress:_

    
    
        There is no infinite chain of (distinct) sufficient reasons.
        That is, there is no infinite sequence F1, F2, F3, ... such
        that "F2 is one of the sufficient reasons for F1", "F3 is one
        of the sufficient reasons for F2", etc.
    

You can't have all three: every directed graph whose nodes are facts and whose
edges are "is one of the sufficient reasons for" either has (i) a dead-end, or
(ii) a cycle, or (iii) an infinite chain.

For those who believe the PSR: which do you give up? Are you ok with cycles,
or with infinite regress?

~~~
westoncb
I think your claim is true for a single moment in time, but if you look at the
Principle of Sufficient Reason as only talking about the _potential_ for facts
to be explained in terms of other facts ("Every fact _can be_ explained in
terms of some other facts")—then I think dead ends at single points in time
are fine.

~~~
justinpombrio
And the graph of all _potential_ facts? Which does that have: dead ends,
cycles, or infinite chains?

~~~
westoncb
Well, that's one way you can approach it: look at the graph of potential facts
instead—but what I was considering was an interpretation of the Principle of
Sufficient Reason where dead ends are fine _at a single point in time_ , which
adds another dimension to the graph and leaves freedom for not having dead
ends, cycles, or infinite chains (as long as 'dead end' is interpreted as a
node not only without outgoing edges, but which cannot develop any at any
future time).

------
barrkel
There's a real risk of storytelling with 'why'. You can construct a narrative
that explains anything - this is probably the primary thing our consciousness
does when communicating to other people - but there's no necessary
relationship between the story and the world, and humans are great at
believing the stories they tell themselves.

Interesting events outside of abstract, simplified, theoretical scenarios
normally have multiple probabilistic causes, and while the causes could be
analyzed at multiple levels - atomic, mechanical, emotional, symbolic - only
the atomic is real. The others are complex webs of stories we tell ourselves,
stories using symbols that hide details because we cannot understand the world
as it is, we can only cope with it in a simplified form. Only as a story.

Our choice of symbols and abstraction level to tell our story creates
artificial entities and forces to explain things. But the boundaries of these
entities are a fiction. The world has no ontology; it's a giant bucket of
interacting particles. The problem with getting serious with this kind of a
principle is that it will break down. When you try and zoom in on the
referents of the symbols, you'll find that they're a lot blurrier than your
stories told you.

~~~
dorgo
The different levels emerge from each other. And I don't think that we can be
sure to have found the most basic one, or even to assume that there is a most
basic level. But the emergent levels are not less 'real' than the more basic
ones. There is more about emergent levels than just to hide details.

~~~
barrkel
Different abstraction levels are normally different ways of talking about the
same physical phenomena. That is, they are parallel; they don't stack. The
most basic one is the one that doesn't exist in our heads and doesn't have a
model with predictions to violate.

What does "real" mean here? I'm using it as a proxy for truth, or perhaps
better, accuracy in a model. That is, if a model of the world makes
predictions about the world, the model is "real" to the degree that the
predictions are correct. But all human models of the world have their limits,
usually forced by our tiny little brains and meagre data input senses.

We take something that we've decided to categorize, and create symbols to
represent commonalities, and theorize relations between the symbols, and test
these theories, and gradually refine a calculus of symbols that we can use to
apply to the world, and the system works, in so far as the commonalities stay
common, and the symbols aim squarely at the average of the referents. But it's
not reality; it's all made up, like mathematics. It's just a story, it's all
in our heads and in narratives we communicate with one another. The symbols
don't stick; the world moves on. People change; humans are animals that evolve
over time, and continue to evolve. We can't even decide what a human is - the
evergreen abortion debate - and other fictions like races, species and planets
etc. shift as we change our mind.

So when you want to get serious about causes, you're going to be using a
system. You're going to be using symbols and relations between symbols; you're
going to define your symbols in terms of commonalities between events and
matter that appear to repeat reliably. But it only works because we have so
little thinking matter, so little data, so little input; it's the only way we
can squeeze the enormity of the world into our tiny heads.

~~~
marknutter
I think this is a consequence of the fundamental problem with a materialist
rationalist view of reality; namely, that when you consider reality to be only
physical matter which can broken down into constituent matter and exists as a
result of cause and effect, all meaning is stripped from the universe and
you're forced to accept the first cause argument.

The real problem comes down to what we mean by "truth". Truth can't simply be
the accuracy of our models of the material world, because the material world
can't tell us anything about how we should act.

------
foldr
An interesting recent defense of the PSR:
[http://quod.lib.umich.edu/cgi/p/pod/dod-
idx/psr.pdf?c=phimp;...](http://quod.lib.umich.edu/cgi/p/pod/dod-
idx/psr.pdf?c=phimp;idno=3521354.0010.007)

The article itself has a rather flowery style, but there's a summary of the
main argument and discussion of it here:
[http://edwardfeser.blogspot.co.uk/2014/10/della-rocca-on-
psr...](http://edwardfeser.blogspot.co.uk/2014/10/della-rocca-on-psr.html)

------
baddox
Ctrl-F "regress"

For me, with admittedly less than expert understanding of philosophical
terminology and methodology, the obvious criticism of infinite regress is not
sufficiently addressed.

~~~
tbabb
I did not deeply read the whole article because it's pretty wordy and a lot of
air, but there is a point where it discusses Leibniz "solution", which was
"therefore God". Basically the well-discredited "unmoved mover" argument in a
slightly different cloak. He goes on to try and prove that there cannot be two
identical things in the universe, which I guess he must have done before
anyone knew about fundamental particles.

In reality, it seems to me that if you want to develop a system of
understanding you have to develop a set of axioms and accept them. And by
Goedel's incompleteness theorem, your system cannot be a complete or
exhaustive description of what is true.

~~~
coldtea
> _He goes on to try and prove that there cannot be two identical things in
> the universe, which I guess he must have done before anyone knew about
> fundamental particles._

Well, that's still right, whether there are same-ish fundamental particles or
not.

Just a pair of particles being the same in all their aspects doesn't make them
identical. For example they don't occupy the same place in space.

~~~
igravious
I don't know why you're being downvoted. By the very _definition_ of the term
identical if any two things are identical they must be the same in all
respects including spatial and temporal location. So fundamental particles are
very much _not_ identical in this sense.

Of course there are not two identical things in the universe. Because being
identical they're the same thing, aren't they? It's called the identity of
indiscernibles.
[https://en.wikipedia.org/wiki/Identity_of_indiscernibles](https://en.wikipedia.org/wiki/Identity_of_indiscernibles)

And one may disagree with the "unmoved mover" (let's call it an) axiom but if
one takes that as given then it is plain to see that Leibniz's argument holds.
And say you actually do disagree with it as an axiom then you have a bigger
problem, what Umberto Eco called the most intractable problem of all, the
problem that generates all other problems, namely, "Why is there something
rather than nothing?"

~~~
mannykannot
I did not downvote coldtea, and I would have preferred those who did so to
explain their reasoning instead, but I have offered up an argument that works
equally well against your first paragraph: the existence of bosons.

Eliezer Yudkowsky has made an argument against doing epistemology by intuition
[1]. Famously, Henri Bergson tried to use his intuition about time to dismiss
special relativity, and while he may have swayed the Nobel prize committee
[2], his ideas were swept away by history.

Turning now to your last paragraph, it is like saying Bernie Madoff's clients
were wealthy because the arithmetic in their statements was correct. Also, one
cannot validly argue against the rejection of a self-serving axiom on the
grounds that doing so leaves problems unsolved.

[1]
[http://lesswrong.com/lw/q1/bells_theorem_no_epr_reality/](http://lesswrong.com/lw/q1/bells_theorem_no_epr_reality/)

[2] [http://nautil.us/issue/35/boundaries/this-philosopher-
helped...](http://nautil.us/issue/35/boundaries/this-philosopher-helped-
ensure-there-was-no-nobel-for-relativity)

~~~
mannykannot
I posted the wrong link for reference 1 - this gets directly to the point:

[http://lesswrong.com/lw/ph/can_you_prove_two_particles_are_i...](http://lesswrong.com/lw/ph/can_you_prove_two_particles_are_identical/)

------
woodandsteel
The PSR seems to assume that the reasons are understandable by human
intelligence, and hence the human mind, like a god, has no limits.

Philosopher Colin McGinn argues that our brains were designed for dealing with
practical matter in living, and so some things, like the mind-body problem are
simply beyond our understanding.

------
BucketSort
I recently started studying Leibniz in my spare time. I found this book to be
a delightful introduction:

[https://www.amazon.com/Leibniz-Very-Short-Introduction-
Intro...](https://www.amazon.com/Leibniz-Very-Short-Introduction-
Introductions/dp/0198718640)

------
cs702
Kurt Gödel had something to say about this. He proved that no formal system
that is consistent is capable of proving (i.e., providing a sufficient reason
for) all statements made within the system, including whether the formal
system is consistent:

[https://en.wikipedia.org/wiki/G%C3%B6del's_incompleteness_th...](https://en.wikipedia.org/wiki/G%C3%B6del's_incompleteness_theorems)

No matter how we choose to model the world, there will always be statements in
our models for which we won't be able to find or discover a sufficient reason.

------
manicmonad
Why does this post exist?

~~~
sdenton4
To encourage you to keep asking 'why' until you hit on something
interesting...

~~~
jpttsn
I could argue that sometimes you won't find anything interesting, but that's
probably interesting, defeating my example.

