You are viewing the historical archive of The Philosophy Forum.
For current discussions, visit the live forum.
Go to live forum

Does the principle of sufficient reason lead to a barber paradox?

Wheatley October 07, 2018 at 21:39 6875 views 15 comments
The SEP provides is a simple formulation of the PSR: For every fact F there is sufficient reason for why F is the case. Which means all facts have an explanation. If all facts have an explanation, then either a fact is explained by some other fact, or is not. If a fact is not explained by some other fact then the only other option for its explanation is itself (a self-explanatory fact). There is no fact left unexplained.

If the PSR is true, then there should be a set of facts that explain ((and only explain) edited) the set of facts that aren't self-explanatory. Does that set of facts explain itself? If it does explain itself, then it doesn't. If it doesn't explain itself, then it does. This is similar to the barber paradox, where the barber shaves ((and only shaves) edited) the beards of all men who do not shave themselves. Does the barber shave himself? If the barber does shave himself, then he doesn't. If he doesn't shave himself, then he does.

Thoughts?

Comments (15)

Dfpolis October 07, 2018 at 23:49 #218594
I fail to see why the set of facts that explain the set of facts that aren't self-explanatory can't include a self-explanatory fact.

As for the Barber Paradox as you have stated it, there is nothing to prevent someone from shaving all who do not shave themselves and shaving himself. If you want the premise to be the Barber shaves all the beards of those who do not save themselves and only those beards, that premise is provably false.
Wheatley October 08, 2018 at 00:44 #218611
Quoting Dfpolis
I fail to see why the set of facts that explain the set of facts that aren't self-explanatory can't include a self-explanatory fact.

I meant to say, the set of facts that explain, and only explain, the set of facts that aren't self-explanatory.

Quoting Dfpolis
As for the Barber Paradox as you have stated it, there is nothing to prevent someone from shaving all who do not shave themselves and shaving himself. If you want the premise to be the Barber shaves all the beards of those who do not save themselves and only those beards, that premise is provably false.

I agree.

Dfpolis October 08, 2018 at 01:01 #218618
Quoting Purple Pond
I meant to say, the set of facts that explain, and only explain, the set of facts that aren't self-explanatory.


The problem is that to avoid an infinite regress, you need at least one self-explaining fact that explains all below it.
Shawn October 08, 2018 at 01:04 #218620
Quoting Dfpolis
The problem is that to avoid an infinite regress, you need at least one self-explaining fact that explains all below it.


Or you can have brute facts upon which all other facts rest on. Hence, modal logic?
Dfpolis October 08, 2018 at 01:40 #218631
If you allow brute facts you reject the PSR and with it the logical foundations of science.
Wheatley October 08, 2018 at 05:58 #218738
Quoting Dfpolis
The problem is that to avoid an infinite regress, you need at least one self-explaining fact that explains all below it.

And why would we want to avoid an infinite regress?
Dfpolis October 08, 2018 at 08:13 #218762
Reply to Purple Pond Because it can be shown by mathematical induction that an infinite regress of concurrent causes can not be a complete explanation.
Wheatley October 08, 2018 at 08:33 #218766
Reply to Dfpolis Why do we need a complete explanation?

It seems like you want to hold onto the PSR when that is the very contention that I am attempting to dismantle.
MindForged October 08, 2018 at 12:55 #218804
Quoting Dfpolis
If you allow brute facts you reject the PSR and with it the logical foundations of science.


You might well reject the PSR as a metaphysical principle (as most scientists do) while still doing as Hume suggested and retain it as an Epistemic principle.
Dfpolis October 08, 2018 at 17:40 #218859
Quoting MindForged
You might well reject the PSR as a metaphysical principle (as most scientists do) while still doing as Hume suggested and retain it as an Epistemic principle.


Putting aside your unsupported sociological claim, yes, some people are quite irrational. How can we know there is a sufficient reason if there is no sufficient reason to know?
Dfpolis October 08, 2018 at 17:58 #218862
Quoting Purple Pond
It seems like you want to hold onto the PSR when that is the very contention that I am attempting to dismantle.


All the PSR states is that every operation is the operation of something able to so operate. How can you dispute that? Do you claim that beings can perform operations they are intrinsically incapable of? Or do you claim that some operations are not acts of an operator? If you do, you are reifying non-being, because anything capable of acting in any way exists.
MindForged October 08, 2018 at 22:20 #218902
Quoting Dfpolis
Putting aside your unsupported sociological claim, yes, some people are quite irrational. How can we know there is a sufficient reason if there is no sufficient reason to know?


What a whomping non sequitur. The inability to know something does not entail there is no sufficient reason for why something is the case.
Dfpolis October 08, 2018 at 22:27 #218904
Quoting MindForged
What a whomping non sequitur. The inability to know something does not entail there is no sufficient reason for something being the case.


I think you have it backward. My claim is that that if there is no sufficient reason in reality, we cannot know that there is a sufficient reason. This was in response to your suggestion:

Quoting MindForged
You might well reject the PSR as a metaphysical principle ... while still ... retain[ing] it as an Epistemic principle.

MindForged October 08, 2018 at 22:34 #218908
Quoting Dfpolis
I think you have it backward. My claim is that that if there is no sufficient reason in reality, we cannot know that there is a sufficient reason. This was in response to your suggestion:


You have my point backwards, actually. You can demand that one must give a reason for what they claim to know because otherwise we would believe anything whatsoever. But that doesn't mean there will actually be a reason for why something is the case. An epistemic claim is not of a kind with the world. (Since you didn't see it probably, here was the update to my last post)

You seem to have confused my point. We can know X is the case despite there being no metaphysical explanation for why it is so. In fact, the PSR is inescapably being formulated in just this way.

A common justification for the PSR is that if the PSR were not true, then things would just happen at random for no reason at all. The obvious assumption here is that the reason this randomness doesn't occur is *because* of the PSR. Which is patently circular. The PSR cannot be extended to the... extent which would be needed to make it a metaphysical principle. Any attempt to do so will either be circular or will in fact invalidate the PSR from being a metaphysical principle (because the PSR ends up holding in virtue of nothing, which contradicts the PSR).
Dfpolis October 08, 2018 at 23:22 #218924
Reply to MindForged Thank you for the clarification.

Yes, one can deny that things occur for an adequate reason, but it is irrational to do so. How can anything come to pass if the conditions of its genesis are inadequate to produce it? Claiming that it can is making the absurd claim that what is inadequate is adequate

Randomness is completely irrelevant. The only relevant consideration is adequacy.