If the only thing in nature that is naturally reasonable is man, then what right do we have to declare that the rest of nature must follow along and be reasonable? We know a very little of what is in nature, maybe there are areas in nature where the PSR does not hold, how would or could we know, unless we say reality must conform to our understanding.

Oh, I am not faulting you for not laying out an entire epistemology right here and now. My point is that historically* the PSR has meant something stronger and more specific than just having some reasons or motives or inclinations for believing this or that. Why even talk about some capital-P Principle if it is something so broad and vague?

* and contemporaneously, although it seems that the PSR, at least its less restricted versions, has rather fallen out of favor outside the circle of Christian theologians.

What usually distinguishes a PSR from any old belief system are more stringent requirements for sufficient reasons. You cannot just give a half-arsed excuse or say "Screw it, that's good enough reason for me!" You are supposed to doggedly pursue the chain of reasoning until some satisfactory resolution - a necessary state of affairs in the strongest formulations of the PSR.

historically the PSR has meant something stronger and more specific than just having some reasons or motives or inclinations for believing this or that.

And it still does for those who uphold it - such as Della Rocca. Framed in terms of "everything has an explanation" it turns out that for him the acceptable explanations are either citing causes or citing logical entailments, so it turns out to be more precisely "everything is caused or logically entailed by something else". This places some objective, or at least non-subjective, restriction on what will satisfy the PSR at any given time in the evolution of thought - not just any old excuse will do. Nevertheless, the notions of logical entailment and causation are not fixed (the former is probably more resistant to change than the latter, granted). This would also mean that although it is a restrictive principle, the meaning of the PSR evolves - citing tree spirits as the cause of noise in a forest no longer cuts the mustard, even if there are some people who might want still to believe in tree spirits.

If the only thing in nature that is naturally reasonable is man, then what right do we have to declare that the rest of nature must follow along and be reasonable? We know a very little of what is in nature, maybe there are areas in nature where the PSR does not hold, how would or could we know, unless we say reality must conform to our understanding. — Cavacava

If we just say "reason" and leave it at that, then either we are making PSR an epistemological principle, or we are making some rather extravagant claims about the world somehow being imbued with "reason" (well, perhaps not so extravagant if you are a deist or a pan-psychist of some sort).

The trouble with a purely epistemological, regulative PSR is that it can easily dissolve into a banality. "We should always be looking for reasons, always try to make sense of the world" - well, who is going to argue with that?

PSR only really gets its teeth when it acquires some metaphysical commitments, as when "reasons" are cached out in terms of causes or entailments (@MetaphysicsNow).

It's not that we should look for sufficient reasons, it's that we have no choice but to believe that they exist.

It's a basic principle that pertains to the way we think. Whether the world conforms to our modelling is a separate issue.

We certainly seem to have reason-seeking instincts, but I wouldn't go so far as to say that we cannot help it. Chance, brute facts - these remain conceivable concepts, even if some would like to deny their actuality.

Chance doesn't signify causeless. The die lands with the 2 face up by chance. One still assumes there is a cause.

No, when I say "chance" I mean absence of reason or cause. You can use a different word if you like.

You might have a special ability to conceive the causeless. Just put that to the side if you dip into Leibniz or Schopenhauer. They had more trouble with it than you have.

I'd like to put together some thoughts.

I have pretty much been a subscriber to logical atomist and Leibniz monadology. To assume the PoSR, it seems that the world must be assumed to be at the core, logical, and orderly. I also wanted to outline that just because something might be unintelligible, does not mean that it cannot happen, to say so would be a gross anthropocentric POV to hold.

Anyway, those issues aside. I have been reading much from this highly edifying and interesting exchange between various scholars on the topic, and am intrigued by the underlying physics that might presuppose the PoSR. One thing that isn't mentioned is the relationship between time and the PoSR. I was wondering if anyone would care to explain the PoSR and 'time'.

Another way to ask this question is to wonder if Quantum Mechanics obeys causality.

The PSR is these days often expressed, for example by Della Rocca, as the claim that everything has an explanation, and so the notion of sufficiency "disappears" in that formulation. So, let's say that someone proffers that A is explained by B. If your point about sufficiency (based on reading your first post on Heidegger) is that another person could come along and say "that's not enough of an explanation, because it has not been explained why A rather than C" , then (provided that A and C are somehow exclusive of each other, e.g. logically or physically) at least two responses seem available:

1) In explaining A by B, at the same time why A and not C is explained since C is excluded by A.
2) An explanation ofsomething different is being required; an explanation of C's exclusion by A.

If, however, C is entirely unconnected to A, then the question "why A and not C" would make little sense and so pushing the "that's not enough of an explanation" would be meaningless in the context. — MetaphysicsNow

Another line of thought - in truth, the only one that makes sense of the PoSR to me - is the Leibnizian one of grounding sufficiency in the 'nature' of 'the thing itself': "All predication has some foundation in the nature of things" (Leibniz, Discourse). Ignoring, for now, the fact that Leibniz construes nature in terms of 'predication', the import of this is that it turns the PoSR into a search for what Leibniz refers to as an ratio existendi: a reason for existence, which differs from the ratio essendi of the principle of identity (which bears only on entities insofar as they have logical consistency). In other words, the PoSR takes us 'out of' logic and 'into' existence: it forces one to think about the question of individuation: of the facts that bear upon this particular thing and no other ('inexchangable' with any other logical substitute).

It's hard to really flesh this out without developing an entire philosophy, as it were, but yeah: to think in terms of things that exist in space and time (and not abstract logical space), and to think in terms of individuation: those are the two imperatives forced upon anyone who wants to take the PoSR seriously, as I understand it.

it forces one to think about the question of individuation... — StreetlightX

...in the light of the intellect's insistence on universal inter-relatedness. The individual, as a concept, stands out against a background of wholeness (as the black dot is dependent on the white background, or pink.)

You might have a special ability to conceive the causeless. Just put that to the side if you dip into Leibniz or Schopenhauer. They had more trouble with it than you have. — frank

I don't think it takes any special ability. We naturally think in terms of chance and contingency.

In our ordinary thinking we hold some things as given (at least until we decide to hold them up for scrutiny) - those are brute facts. Other things are unknown, though they may be subject to some constraints (at least until we learn something new or recall something we had left out of the consideration) - those are chances. So we live and think as if there were brute facts and chances - whether this is in fact the case (and whether the question even makes sense) is another matter, but this reasoning scheme is natural to us.

The same has always been the case in science*. In any given scientific framework or theory some things (the assumptions and posits of the theory) are taken as brute facts, and depending on the theory, there may be chancy things as well.

It takes a philosopher of a certain bent to say: Wait a minute, these are not real chances, they only seem chancy to us due to our ignorance. And these facts that we take as brute must have some explanation.

* The special focus on quantum mechanics when it comes to chanciness is a result of reductionist thinking, where it is assumed that quantum mechanics reveals the true workings of the world, while all those other "special" theories, such as classical statistical mechanics or the theory of evolution in biology are only half-truths, convenient approximations.

The causeless is a fixture of thought traditionally associated with divinity. I'm reading about Heidegger's rejection of ontotheology (seeing all things as emerging from predecessors which ultimately arise from the causeless ground of Being.)

The causeless is still inconceivable, well because of the PSR.

I obviously wasn't talking about this "causeless ground of being." Whatever that is, I don't think it is required to conceive of brute facts and chances, as I explained above.

Suppose we find it reasonable to conclude that the Big Bang was causeless. The PSR doesn't say that we're unable to conceive the bang in some way. We can be fully confident that we're onto a brute fact. The PSR notes that the causeless part is inconceivable. Inconceivable doesn't mean nonexistent. It means beyond our ability to model in thought.

I think your definition of chance is peculiar, but the same angle would apply to any sort of causelessness.

What usually distinguishes a PSR from any old belief system are more stringent requirements for sufficient reasons. You cannot just give a half-arsed excuse or say "Screw it, that's good enough reason for me!" You are supposed to doggedly pursue the chain of reasoning until some satisfactory resolution - a necessary state of affairs in the strongest formulations of the PSR. — SophistiCat

And it still does for those who uphold it - such as Della Rocca. Framed in terms of "everything has an explanation" it turns out that for him the acceptable explanations are either citing causes or citing logical entailments, so it turns out to be more precisely "everything is caused or logically entailed by something else". — MetaphysicsNow

Suppose we find it reasonable to conclude that the Big Bang was causeless. The PSR doesn't say that we're unable to conceive the bang in some way. We can be fully confident that we're onto a brute fact. — frank

I haven't been denying "stringent requirements for sufficient reasons". But as I pointed out, and as @MetaphysicsNow alluded to with the 'tree spirits' example, the stringency of reasons is always relative to an overall context or paradigm within which they cohere. Of course there is always necessarily a terminus of explanation.

The terminus is simply where our actual explanations stop at some belief. If the belief is unsupported it could be on account of the fact that the belief relies on the existence of states of affairs which do not obtain and is thus incorrect. But if a belief is correct, In terms of Aggrippa's Trilemma, it could be supported by either a brute fact, a state of affairs that it is self-causing, or an infinite chain or nexus of causation that we can never get to the bottom of.

So in terms of @Frank's 'Big Bang' example, it could be, as he says a brute fact, and will remain so for us, even though it could alternatively be a self-caused, and thus in principle, self-explanatory, event. But confirmation of the latter possibility would seem to be closed to us; we cannot tell whether it is simply a brute fact, is self-caused or even caused by some other set of unknowable conditions.

I have been arguing along the lines of what @MetaphysicsNow describes as Della Rocca's definition of acceptable explanations: "either citing causes or citing logical entailments', so, "everything is caused or logically entailed by something else". But I would put a caveat there, that the overall context, the Universe, reality, being, or whatever you want to call it. at the limits of both its micro and macro dimensions, obviously cannot be caused by "something else", at least not by something else within the system.

So whether the Big Bang is uncaused, self-causing, or caused by something unknowable, we are not precluded from conceiving it as an event in terms of its observed consequences. But it can only be understood in terms of its consequences, a fact which itself supports the PSR, it cannot be understood 'in itself'. So, in other words, events like the Big Bang or the decay of uranium atoms are conceivable in terms of their consequences, but not conceivable in themselves.

This goes back to what I said earlier, and that also alludes to if I am not mistaken; that sufficient reason for such events is found in their own natures. I would add that the sufficient reason for believing in such events is found in their observed consequences, and the consistent and coherent ways in which those are modelled to produce the ideas of those events. It must also be allowed that what are, within one paradigm, sufficient reasons, can indeed become insufficient reasons within another.

:up:

Suppose we find it reasonable to conclude that the Big Bang was causeless. The PSR doesn't say that we're unable to conceive the bang in some way. We can be fully confident that we're onto a brute fact. The PSR notes that the causeless part is inconceivable. Inconceivable doesn't mean nonexistent. It means beyond our ability to model in thought. — frank

So in terms of Frank's 'Big Bang' example, it could be, as he says a brute fact, and will remain so for us, even though it could alternatively be a self-caused, and thus in principle, self-explanatory, event. But confirmation of the latter possibility would seem to be closed to us; we cannot tell whether it is simply a brute fact, is self-caused or even caused by some other set of unknowable conditions. — Janus

Traditional proponents of the PSR, such as Spinoza and Leibnitz, as well as modern proponents like Della Rocca(1), Pruss(2) and Feser(3), do not accept brute facts. As Spinoza put it,

For each thing there must be assigned a cause, or reason, both for its existence and for its nonexistence. — Spinoza

Or,

There is a sufficient reason or adequate necessary objective explanation for the being of whatever is and for all attributes of any being. — Dictionary of Scholastic Philosophy

Even in his proposed weakened form of the PSR Pruss requires an account for at least the possibility of every contingent truth.

So whatever you two are arguing for, it does not look like familiar forms of the PSR, although there seems to be a strain of rationalism that is recognizable.

Moreover, when you say that some fact or state of affairs that lacks an explanation is "inconceivable" or "unintelligible" you don't seem to mean anything other than it does indeed lack an explanation, so you are not really saying anything at all - you are just restating the premise.

Or do really mean to say that something that lacks an ultimate explanation is inconceivable?



But that is nonsense. If we can describe and discuss something, then surely it is at least conceivable. As I argued earlier, we can and do conceive of things, without at the same time being aware of their causes or explanations. We do so all the time: in our everyday reasoning we always take some things for granted. When the need arises, we can put to question what was previously an assumption, but at the moment when we make use of the assumption, it does not matter whether it is necessary or contingent, and whether if it is contingent it has an explanation. Likewise, when we flip a coin, or when something happens "by chance," it does not matter to us whether the event was really, ontologically random or not - for all practical purposes, there was no explanation for why that event happened instead of one of its possible alternatives. We wouldn't think of it as random otherwise.

So psychologically, unexplained and chancy things are very much conceivable, and commonplace. Appealing to our psychological intuitions and using words like "inconceivable" and "unintelligible" rhetorically does not work in favor of the PSR.

The same goes for explanations. Proponents of the PSR, such as Feser, argue that an explanation that only goes so far as reducing one contingent thing to another contingent thing is not really an explanation. But that appeals to some contrived and question-begging notion of explanation, which is at odds with the way we actually employ the concept of explanation in our everyday life and in science.

(1) Michael Della Rocca: PSR (Philosopher’s Imprint, 2010)

(2) Alexander Pruss: A restricted Principle of Sufficient Reason and the cosmological argument (Religious Studies, 2004)

(3) Edward Feser: Can we make sense of the world? (2011)

Spinoza did accept an exception to the PSR. Your post deserves more than I can offer now. My stake in it is just that grasping the PSR is critical for understanding Schopenhauer.

If you're thinking that defiance of the PSR can be found in cases of just not knowing the cause of X while accepting that there is some cause: no, that's not how it works.

If you're thinking that defiance of the PSR can be found in cases of just not knowing the cause of X while accepting that there is some cause: no, that's not how it works. — frank

No, I agree, most typically the PSR implies the existence of a cause, whether known or not. My point when talking about our common-sense reasoning is that we do not, in fact, always assume the existence of a cause. Things that we (however fleetingly) take for granted are causeless in effect: the existence or absence of a cause makes no difference to our reasoning.

The same is true for scientific explanations: once we adopt some theory as our explanatory framework, it does not matter for us whether the theory and it posits can be further reduced to a causeless ground of all being or some such; giving account of phenomena in terms of the theory counts as providing an explanation regardless.

So whether the Big Bang is uncaused, self-causing, or caused by something unknowable, we are not precluded from conceiving it as an event in terms of its observed consequences. But it can only be understood in terms of its consequences, a fact which itself supports the PSR, it cannot be understood 'in itself'. So, in other words, events like the Big Bang or the decay of uranium atoms are conceivable in terms of their consequences, but not conceivable in themselves. — Janus

But if there are uncaused events, like the big bang and nuclear decay, the PSR is refuted, surely?

The same is true for scientific explanations: once we adopt some theory as our explanatory framework, it does not matter for us whether the theory and it posits can be further reduced to a causeless ground of all being or some such; giving account of phenomena in terms of the theory counts as providing an explanation regardless. — SophistiCat

What if the only theory we have is non-explanatory, such as the Shut-up-and-Calculat version of quantum mechanics, or the Copenhagen Theory?

Things that we (however fleetingly) take for granted are causeless in effect: — SophistiCat

True. And that highlights how thoroughly intellectual the PSR is. It's upon reflection that the demand for explanations appears along with the assumption that they must be out there even if unavailable.

People who make use of the PSR are going to have to explain how basic principles of thought relate to the way the world is in actuality.

No, I agree, most typically the PSR implies the existence of a cause, whether known or not. — SophistiCat

But what if you can prove there is no cause, that there cannot be a cause, and back that up with real world experiments?

Traditional proponents of the PSR, such as Spinoza and Leibnitz, as well as modern proponents like Della Rocca(1), Pruss(2) and Feser(3), do not accept brute facts. As Spinoza put it, — SophistiCat

But Spinoza does allow for self-causing substance. In fact according to Spinoza all causation finds its ultimate terminus is "God or Nature" (deus sive natura).

So psychologically, unexplained and chancy things are very much conceivable, and commonplace. Appealing to our psychological intuitions and using words like "inconceivable" and "unintelligible" rhetorically does not work in favor of the PSR. — SophistiCat

The weakness of this argument lies in the assumption that when people think of events as "unexplained or chancy", they are believing that the events are utterly random in the sense of having no cause at all. No one, if they thought about it, would deny that when the die is tossed, it interacts with the air and the surface it lands upon in ways which determine what face will show up. Events are only chancy for us insofar as we cannot predict outcomes, because we have no way of predicting the future, given that we only have a minimal grasp of all the determining factors.

The only events that I can think of which are considered by many to be truly causeless are microphysical events and the Big Bang. These are both global events in different senses; the global status of the Big Bang is obvious, and the global status of microphysical events consists in their purported ubiquity. There are no local events that are thought to be truly random and 'one-off', no events that contravene what is judged to be the invariance of nature.

Or do really mean to say that something that lacks an ultimate explanation is inconceivable? — SophistiCat

I don't think anyone genuinely believes that any event lacks an ultimate explanation. It is the very idea that any event could have no ultimate explanation that is inconceivable.

No, because those events, as I explained in my previous post, are either global (the Big Bang) or statistically invariant. In the case of the Big Bang the conditions for its advent are completely unknown, and we cannot say it is statistically invariant because it is the one and only truly causeless event (in the sense that it could have no cause from within the system for obvious reasons).

In the case of microphysical events, they are statistically invariant, which points to the them being the result of the nature of the system itself. The problem is that the general tendency is to think only in terms of efficient causation. Microphysical events might have no causes more fundamental than themselves but may be the result of global 'formal' or 'final' constraints that come about only at a certain stage in the evolution of the system itself.

No doubt @apo would have more to say on this.

No, because those events, as I explained in my previous post, are either global (the Big Bang) or statistically invariant. In the case of the Big Bang the conditions for its advent are completely unknown, and we cannot say it is statistically invariant because it is the one and only truly causeless event (in the sense that it could have no cause from within the system for obvious reasons). — Janus

You only need one uncaused event to refute PSR.

I happen to disagree with you about the status of knowledge about the big bang, and your apparent assertion that "statistical invariance" can have any meaning or significance. However, if you assert the existence of an uncaused event, then it's curtains for a principle that claims no such thing can happen.

In the case of microphysical events, they are statistically invariant, which points to the them being the result of the nature of the system itself. The problem is that the general tendency is to think only in terms of efficient causation. Microphysical events might have no causes more fundamental than themselves but may be the result of global 'formal' or 'final' constraints that come about only at a certain stage in the evolution of the system itself. — Janus

Uncaused microphysical events are incompatible with PSR, it's that simple. And, as we know, there are certain famous experiments that demonstrate, without loopholes, the existence of uncaused events.

But Spinoza does allow for self-causing substance. In fact according to Spinoza all causation finds its ultimate terminus is "God or Nature" (deus sive natura). — Janus

Yes, the "ultimate terminus" is the Achilles hill of the unrestricted PSR, and philosophers have tied themselves into knots wrangling with concepts like causa sui. Although I think that being more critical and broadminded about the concepts of cause and explanation would be helpful here (and this goes for the Agrippa's Trilemma as well).

The weakness of this argument lies in the assumption that when people think of events as "unexplained or chancy", they are believing that the events are utterly random in the sense of having no cause at all. No one, if they thought about it, would deny that when the die is tossed, it interacts with the air and the surface it lands upon in ways which determine what face will show up. Events are only chancy for us insofar as we cannot predict outcomes, because we have no way of predicting the future, given that we only have a minimal grasp of all the determining factors. — Janus

What conclusions people reach when they specifically question things that they previously treated as "unexplained or chancy" will vary depending on the situation, available information and background beliefs. But this is not what I wanted to address in this argument. What I wanted to address was the notion that a PSR of some sort is indispensable to our everyday thinking (basic principles of thought @frank) and to science. I argue the opposite. Both everyday thought and science are oblivious to the PSR, unless they specifically focus on the question.

I don't think anyone genuinely believes that any event lacks an ultimate explanation. It is the very idea that any event could have no ultimate explanation that is inconceivable. — Janus

Well, this is not so much a philosophical question as a sociological one, and I believe you are very much mistaken in thinking that everyone is a causal determinist and believes in an unrestricted PSR. I know I don't. Della Rocca (PSR) bemoans the current low standing of the PSR among philosophers and scientists alike:

It sometimes seems as though, over the last, say, 271 years, a great deal of the best efforts of the best philosophers have been devoted to a direct frontal assault on the PSR. Despite their obvious and profound differences, Hume and Kant, for example, made it their mission to articulate and argue for a world-view structured around the claim that the PSR is simply false. Such attacks have been enormously influential to the point that they are simply taken for granted and philosophers now tend to presuppose — un-self-consciously operate under the assumption — that the PSR is false[...] And, perhaps even worser, there has been the testimony of contemporary physics which, in the eyes of many, tells directly and empirically against the PSR: for isn’t it a hallmark of contemporary physics that there can be certain facts without explanation? — Michael Della Rocca

ETA: The cosmologist Sean Carroll is one of those philosophically-minded scientists who rejects the PSR, for example in his recent article Why Is There Something, Rather Than Nothing?:

It seems natural to ask why the universe exists at all. Modern physics suggests that the universe can exist all by itself as a self-contained system, without anything external to create or sustain it. But there might not be an absolute answer to why it exists. I argue that any attempt to account for the existence of something rather than nothing must ultimately bottom out in a set of brute facts; the universe simply is, without ultimate cause or explanation. — Sean M. Carroll

ETA2: For fairness's sake, Paul Davies is another cosmologist who takes the opposite view, e.g. in this OpEd.

, Hume and Kant, for example, made it their mission to articulate and argue for a world-view structured around the claim that the PSR is simply false. — Michael Della Rocca

Hmm, my impression is that transcendental philosophy - Kant and his successors - has a more complex relation with the PSR than is generally acknowledged. After all, the transcendental was invoked precisely to secure the necessity of thought with respect to the world; that is, the transcendental was invoked in order to stave off the spectre of arbitrariness with respect to thought, so that truth would find itself on a more secure footing than Hume could give it. And for the post-Kantians - Hegel and Maimon in particular - the problem with Kant was that the very categories of thought were themselves considered to be too arbitrary, and in need of further grounding - hence the various 'philosophies of the Absolute' that followed in Kant's wake (Schelling, Fitche, Hegel).

All of which is to say that there is a more subterranean hewing to the PSR - rejigged and reworked - than I think is commonly acknowledged.