Is logical necessity a brute fact? — RussellA

No, nothing is a brute fact under the unrestricted PSR. Logic has a reason for existing, as provided in the OP under section "Argument in defence of the PSR". The section explains why logic is a first principle of epistemology. Then, the reason why logic exists on the metaphysics side is because, being a first principle of epistemology, it is also a first principle of metaphysics; i.e. logic is part of the fabric of reality. With that, the existence of the laws of logic is explained inherently (reason type 1 in the OP section "PSR in Metaphysics").

is the logical necessity that "A triangle has three sides" a brute fact? — RussellA

No, this is a logical necessity only because it describes its own definition, which is man-made. "A triangle, defined as a shape that has 3 sides, has 3 sides". A=A.

We're going on circles. — Clearbury

Very well. Then we can drop this topic.

You haven't answered the question. What explains it [logic]? — Clearbury

I have provided the reason why we know that logic exists on the epistemology side. Then the reason why logic exists on the metaphysics side is because, being a first principle of epistemology, it is also a first principle of metaphysics; i.e. logic is part of the fabric of reality. With that, the existence of logic is explained inherently (reason type 1 in the OP section "PSR in Metaphysics").

What is deduced from a questionable principle is questionable. — Fooloso4

What is questionable about the PSR?

Positing a super-natural being in order to explain what you cannot explain is question begging. It assumes what is in question, that there must be a comprehensive reason for what is. — Fooloso4

I did not use the word "super-natural". We should simply try to follow the rules of the PSR to its logical conclusion. And my conclusion is that a thing whose existence is essential is necessary to explain the existence of all other contingent things, including the laws of nature. If you can point out an error in the reasoning, then fair, and if not, then the conclusion stands.

Triangles are abstractions, and don't exist in the real world. — Relativist

Sure. The reason I used the example of a triangle is because it is easy to understand its identity or essence, and thereby also understand its essential and non-essential properties.

But some things in the real world also have metaphysical identities or essences. Even if we suppose that the world is merely physical, which means that everything supervenes on matter and energy, then at least matter and energy have identities (i.e. as matter is not the same thing as energy, they have different identities), and thus also have essential properties. E.g. matter has the essential properties of having a mass, volume, shape, etc. So, if a thing is made of matter, then it necessarily follows that it has a mass.

No internal reason is needed for a first cause to exist necessarily. A first cause cannot exist contingently, because it is logically impossible for it to be contingent upon anything*. So there's no need for the (ad hoc) contrivance of treating a term in logic as an ontological property. — Relativist

If I understand correctly, you say that the first cause's existence is necessary, but only because there is no prior cause and not because its existence is an essential property of its identity. But then, how do you explain the fact that its existence is necessary, if not inherently? If this fact is left unexplained, then it violates the PSR.

You also give the examples of things that don't have a sufficient reason, but rather logical necessity, such as "All bachelors are unmarried". — RussellA

Logical necessity is a type of sufficient reason. It is reason type 1 in the OP section "PSR in Metaphysics".

What the principle of sufficient reason says is that there were causes sufficient to bring P about. Causes sufficient to bring about P can be much more than is necessary. — Clearbury

That's the PSR on the metaphysics side. The PSR on the epistemology side demands that explanations be no more than necessary. This is because the PSR is so strict that it not only demands a reason for the data, but also demands a reason to posit the explanation itself. Thus, the explanation is posited to account for the data, and the data must support the explanation. If the explanation is more than necessary, it means it is not supported by the data, and thus it fails the PSR.

But the principle of sufficient reason - which says that everything has an explanation - must now be applied to the law of non-contradiction. What explains why it is true? — Clearbury

Logic is a first principle of epistemology. This is defended in the OP under section "Argument in defence of the PSR", steps 1 to 4. As a first principle of epistemology, an appeal to logic is a valid form of reasoning that fulfills the PSR.

The concept of "necessary" applies to logic: e.g. in a valid deductive argument, the conclusion follows necessarily from the premises. — Relativist

Sure, but in the same way, necessity also applies to things with essential properties. E.g. "3 sides" is an essential property of a triangle. Thus, if a thing is a triangle, it logically or necessarily follows that it has 3 sides. Therefore, we can call essential properties "necessary properties".

Why think "necessary" is an ontological (de re) property of any being? [...] I suggest that any first cause (including a natural one) would exist necessarily: it exists autonomously, and without a cause that could account for its contingent existence. — Relativist

Would this mean that this type of first cause exists without a reason, and thus would violate the PSR? Whereas my first cause, the being whose existence is an essential property, has a sufficient reason to exist: it is an internal reason, that is, its existence is explained logically or inherently.

Something does not exist because you posit its existence as necessary. — Fooloso4

I agree, but in this case it is not arbitrary. The existence of a being whose existence is an essential property is deduced directly from the PSR. Since the PSR demands a reason for everything that exists, and since external reasons (i.e. causes) cannot sufficiently explain everything because we run into an infinite regress, then it is necessary to have an internal reason, that is, a being whose existence is an essential property.

This thing whose existence you posit designs the laws of nature that cannot be explained naturally. — Fooloso4

What else could it possibly be? We could entertain that the laws of nature are caused by prior laws, but this only pushes the problem one step back. To avoid the risk of infinite regress, the fundamental laws must be explained by something that requires an explanation but not a cause.

Isn't reason a product of human mind? Reasons don't exist out there in the external world. There are only matter, energy and changes in the world. Reason is an operation of human mind seeking for the causal explanations on the existence and changes. — Corvus

As described in the OP, reason in the context of epistemology can be interpreted as explanation or justification for a claim be true; and reason in the context of metaphysics can be interpreted as cause or grounding for a thing existing.

Even if the world was only physical, there are still causes or grounds for the existence of particular physical things. E.g. The egg is caused by a chicken, etc.

For the proper operations of the inductive reasoning, human observations do need the data to draw the reasoning for the conclusions. Therefore there are many events and existence which have the reasons, and many are unknown due to lack of the data. — Corvus

I agree. The PSR would say that everything that exists has a sufficient reason (or cause or grounding) even if some of these reasons are not known to us.

Since the PSR states that every thing must have a sufficient reason, no exception, then both 2) and 3) would be deniers of the PSR.

Fallacy of misplaced concreteness (i.e. mapmaking =/= terrain). At most the PSR is, "like logic", a foundational property of reason. — 180 Proof

Sure. In other words, the content of mapmaking describes the terrain; and likewise, principles of metaphysics describe the things in fundamental reality. I accept the distinction.

in terms of metaphysics, I think grounding is a more suitable term. — Relativist

Yes that's a clearer way of putting it. It avoids the confusion of whether we speak of a reason why we know something is true versus a reason why a thing exists. So we could rephrase the PSR as: For any claim that is true, there is a sufficient reason for it to be true; and for any thing that exists, there is a sufficient ground for it to exist.

Rather: reason directs us toward truth. Induction doesn't necessarily fund truth, but it tends to lead in the proper direction. — Relativist

Yes I agree. I would add that reason is powerful enough to know its own limitations. Reason knows that induction gives inferences that are the most reasonable yet not certain.

This sounds like you're reifying logic; logic is semantics- it applies to propositions, not to reality. — Relativist

I would still say that logic has value because it reflects outcomes in reality. E.g. logic tells us that 2+2=4; and empirical demonstration shows us that if we put 2 spoons in an empty box and add another 2 spoons, we count 4 spoons in total. But suppose that, for whatever reason, we sometimes counted 3 spoons in total. This would undermine the value of using logic as a tool for finding truth.

No, the principle of sufficient reason says that everything that exists has a sufficient explanation of its existence. It says nothing about simplicity. Note, the more complicated of two explanations is still sufficient to explain. (I think you're conflating sufficiency with efficiency) — Clearbury

The Principle of Parsimony: the simplest explanation that accounts for all the data is the most reasonable one.
Sufficient in the PSR means that an explanation should be neither more than sufficient (i.e. it should be the simplest one), nor less than sufficient (i.e. it must account for all the data); but should be just sufficient.

The first is to insist that some things exist 'of necessity' and hope that this will somehow pass as an 'explanation' of why the thing exists. — Clearbury

Not all explanations are external to the thing explained. Here are examples of things that are explained by an internal reason, that is, out of logical necessity or inherently.
• 2+2=4 because II and II are contained inherently in IIII.
• All triangles have 3 sides by definition, or inherently.
• Same for "All bachelors are unmarried".
• Likewise, if the property of existence is contained in the definition of a thing, then its existence is explained inherently.

This is question begging. It assumes what is in question, namely whether everything in existence can be explained. These three types of reason are based on the existence of things. They do not explain why there is anything at all. — Fooloso4

The traditional answer is: we can posit the existence of a First Cause which has existence necessarily or as an essential property. The existence of this First Cause is grounded by logical necessity (reason type 1 in the OP) because to deny the existence of a thing with necessary existence is a contradiction. Then this First Cause also serves to explain the existence of everything else as their cause, direct or indirect. This summary should serve to explain why there is anything at all.

Well, if we rejected the idea that there is a reason then we would not look for for one, but it does not follow that there must be one. — Fooloso4

That is the point. Where is the data that is sufficient to conclude that everything must have a reason? — Fooloso4

Rejecting the idea that there is a reason would go against our reasoning process, specifically induction which demands sufficient reasons.

It does not explain why there are laws of nature. — Fooloso4

I did not give the specific explanation but I gave the guidance on how to find the explanation. Here are the quick steps to work out the specific explanation:

As per the OP, there are 3 types of reasons: (1) logical necessity, (2) causal necessity, (3) freely chosen or designed. Let's proceed by elimination:
(1) The fundamental laws of nature do not exist by logical necessity because they are not tautologies, and thus denying them does not give a self-contradiction.
(2) The fundamental laws of nature do not exist out of causal necessity from prior laws because they are fundamental, which means not based on prior laws.
(3) By elimination, they are designed.

does not demonstrate that those laws are prescriptive rather than descriptive. — Fooloso4

The laws as we currently know them may be only descriptive, but as per the PSR, there still must be a prescriptive explanation for why matter and energy behave as described by those laws.

C1 - If there is no reason why the lamp turns on, then there is no reason why the lamp turns on earlier or later than the lamp turning off.
C2 - However, if there is no reason why the lamp turns on, then there is no reason why the lamp cannot turn on "at the same time " as the lamp turning off, other than the Law of Non-Contradiction. — RussellA

This is a false dilemma: either everything has a reason or nothing has a reason. Deniers of the PSR do not claim that nothing has a reason; only that not everything has a reason. Most people accept the laws of logic, and accept logical inferences as valid reasons. But they might still also believe that some brute facts exist without reason.

So what is the sufficient reason (why) for the "PSR" (Why) or any so-called "sufficient reason" (why) as such? — 180 Proof

On the epistemology side (knowledge), the reason defending our knowledge of the PSR is provided in the OP section "Argument in defence of the PSR".


On the metaphysics side (reality), indeed the PSR also needs a sufficient reason or explanation for existing. Note that since we know the PSR is true on the epistemology side, we know there must be an explanation for the existence of the PSR even if we don't know what that explanation is.

Nevertheless, here is my suggested explanation: Since the PSR is a first principle of metaphysics, like logic, then it is part of the fabric of reality. As such, the existence of the PSR is explained inherently (reason type 1 as described in the OP section "PSR in Metaphysics").

I mean the reason why there is anything at all. — Fooloso4

If all objects in a set are explained, then the set is also explained. Thus, if all objects in existence are explained, by 1 of the 3 types of reasons as per the OP section "PSR in Metaphysics", then existence is also explained.

A premise is the reason why there must be a reason for what is? — Fooloso4

On the epistemology side, yes, that is, our knowledge of the PSR is defended by that premise.

Although we do employ reason in our search for truth, it may lead us astray. — Fooloso4

Yes I agree. This occurs when we lack data. The best way I know to counter this is to perform empirical tests (when possible) and continue to gather data. Despite that, I still would not go against the laws of reason to find truth.

You posit "laws of nature" as an explanation, but this is problematic for two reasons. First, we might ask what the reason is for the laws of nature. Second, what is the explanation for the causal power of these laws? — Fooloso4

That's fine. Things under the laws of nature are explained by those laws, and the laws themselves also need to be explained. Since there are only 3 types of reasons in the OP section "PSR in Metaphysics", the laws of nature would be explained by 1 of the 3 types.

Randomness simply means that there isn't any self repeating pattern or patterns to be found. — ssu

Sure, a random outcome can have a cause, but it also means there is no reason to have outcome 1 vs outcome 2. Thus, the particular outcome lacks a sufficient reason.

P1 - Let there be an event which could be either event 1 or event 2, where event 1 and event 2 are different.
P2 - The Principle of Sufficient Reason states that if event 1 occurs there must be a reason.
P3 - By the Law of Non-Contradiction, if event 1 occurs then event 2 could not have occurred.
P4- Suppose event 1 occurs without reason.

C1 - From P4, if event 1 occurs then event 2 could have occurred.
C2 - C1 and P3 are contradictory.
C3 - Therefore, if the Law of Non-Contradiction is valid (P3), then events occurring without reason is invalid (P4). — RussellA

I still hold that the relevant propositions must have "at the same time" added to them. So:
P3 - By the Law of Non-Contradiction, if event 1 occurs then event 2 could not have occurred at the same time.
C1 - From P4, if event 1 occurs then event 2 could have occurred, but not at the same time.
C2 - C1 and P3 are no longer contradictory.

Of course the scientific revolution introduces a wholly different conception of reason as mechanical causation. With the banishing of teleological reasoning the idea of reason in that classical sense fell out of favour. — Wayfarer

Yes, the "intellect as a whole" as the image of the cosmos versus "the mathematical model." — Count Timothy von Icarus

It is true that the two models give different types of reasons for the existence of things in the physical world. The old model gives teleological reasons (type 3 in the OP section "PSR in Metaphysics"), and the new model gives reasons of causal necessity (type 2 in the OP section "PSR in Metaphysics"). Both types of reason fulfill the PSR. And I personally side with the new model, at least when it comes to physical things.

The outcome “4” exists from “2+2” by logical necessity

Basically you're saying if you give me an answer I can come up with an equation that comes up with that answer. — LuckyR

Not quite. What I meant was, if we inquire why 2+2 results in 4, then the explanation is that 4 follows out of logical necessity. We could not say that 2+2 causes 4, as though they are separate things. So the point is that, alongside causes, logical necessity is also a type of explanation that fulfills the PSR.

BTW, many, many actual explanations don't initially seem to be the most reasonable explanation. — LuckyR

We can come to reasonable conclusions that are not true — Philosophim

Yes I agree. This occurs when we don't have enough data that points in the right direction. But given enough data, the most reasonable explanation will tend towards the actual explanation. So the trick is to continually gather data and conduct empirical tests (when possible) until we reach a high level of confidence.

Thanks for sharing!

What is the reason for existence? — Fooloso4

If you mean the reason for the existence of a particular thing, then the type of reason is given in the OP under the section "PSR in Metaphysics". In short, there are 3 types of reasons:
1. Internal reason: The existence of a thing is explained by logical necessity or inherently.
2. External necessary reason: The existence of a thing is explained by causal necessity.
3. External contingent reason: The existence of a thing or action is explained by a free choice that is motivated by an end goal.

Or if you mean "existence" as the general concept, then that's just a concept. Concepts are not concrete existing things that need reasons.

What is the reason for thinking that there must be a reason for what is? — Fooloso4

The reason is given in the OP under the section "Argument in defence of the PSR". In short, it follows from the premise that "Reason finds truth".

Ah, gotcha.

P1 - If there can be a fact/event without a reason/cause, then the fact/event could have been other than it is.
P2 - By the Law of Non-Contradiction, a fact/event cannot be other than it is
C1 - Therefore, a fact/event must have a reason/cause

I dispute P2. By the Law of Non-Contradiction, a fact/event cannot be other than it is at the same time.
Suppose true randomness exists such that event 1 occurs without reason. Still, by the law of non-contradiction, event 1 cannot be something else at the same time. But it still occurred without reason.

We can imagine a unicorn in our mind even though there is no unicorn in the world. Does this mean that there is nothing that has caused us to imagine a unicorn in our mind? — RussellA

I believe that something has caused us to imagine a unicorn in our mind. Something like the experience of having seen horses and horns in the world, and we put them together in our mind.

Thanks!

I do not see why the principle of sufficient reason is equivalent to the principle of parsimony. They seem like two quite different principles. [...] — Clearbury

They are still the same. In the principle of parsimony, it is reasonable to pick the simplest of 2 explanations that account for all the data because the less simple explanation is superfluous, that is, more than sufficient. Both principles demand that the explanation or reason be just sufficient, not more, not less.

For example, imagine I think it is false for I think that if it is true, then some things must explain themselves (for not everything can have a cause external to it - as that generates a regress - and nothing can be the cause of itself, as that's a contradiction). As nothing can explain itself, I conclude that some things exist and have no cause of their existence (and thus that the principle of sufficient reason is false). — Clearbury

I agree that a thing cannot be its own cause, yet a thing can explain itself. A cause is not the only way to explain the existence of a thing, as described in the OP under the section "PSR in Metaphysics". Another way is that the existence of a thing is explained inherently or by its own definition. I.e. if a thing possesses existence as an essential property, then its existence would be explained inherently or by its own definition. And this would fulfill the PSR.

Yeah probably. Out of curiosity, would you have a better description of mathematics?

Good point.
I think what you are trying to say is we cannot know with certainty that nature is uniform, that the future will resemble the past. I agree, but I don't see it as an issue in practice: (1) Most people would agree that our reason is a reliable tool to find truth, and our reason uses induction. (2) It has been the case so far that nature is uniform - planes fly pretty well. Thus, while the uniformity of nature is not known with certainty, it is still known beyond reasonable doubt.

one can imagine an event without a cause. — RussellA

This is expected because the test of imagination is associated with logic, and the PSR (which includes causality) is not derived from logic.

Thanks for sharing! Interesting stuff.

Isn't here already the existence of randomness enough? [...] Throw of a dice. This isn't an obstacle for determinism, because if you throw a dice, you will get a dice number. Yet the process is easily and efficiently modeled as the dice number being random (from 1 to 6, if the dice is a cube). — ssu

I know you said this does not refute the PSR; however, I want to clarify that statistical randomness like throwing a dice is not real or metaphysical randomness. We call the outcome of throwing a dice random because we are not fully in control of the outcome; however it is not truly random because it is only a bunch of forces acting on the dice, all of which are determined. I.e., if we were to throw a dice the exact same way every time, then the same outcome would result every time.

Yes I agree. When responding to quantum physics objections, I think I'll use your response first before trying a more elaborate argument like in the OP. Thanks!

Cheers! :victory:

I tagged you in another thread where I said that explanatory theories can be assumed true until falsified. A subtle difference but an important one in my humble opinion. — Agent Smith

Yep, I agree with that. Verification by falsification does not make explanations certain but makes them the most reasonable. To add my 2 cents - these principles of "novacula occami (simplicity) & beauty & elegance" are founded on the more fundamental principle of Sufficient Reason. I describe that principle in my video Part #4, if interested.

The 3rd step however doesn't prove the explanation (2) is true (re abduction aka argument to the best explanation) and so circularity is N/A. — Agent Smith

I think I could keep going, but I'm not sure it is worthwhile. How about we leave it here? Sounds like we are almost in agreement anyways haha.

Honestly, I don't agree with you, but I'm not sure it is worth discussing this any further. It's not really relevant to the original topic in the OP. Unless you really want to keep going, how about we leave it here?

Sure. So the order is: (1) make observations; (2) conceive an explanation that best fits the data; (3) Validate the explanation by making predictions and verify with further data. The third step is the verification by empirical evidence and is essential to the scientific method.

I think you've explained it pretty well. Alvin Plantinga would be proud of you. You've famed a formation argument for reformed epistemology in an accessible way. — Tom Storm

Thanks! And I'll read up on that Plantinga fella.

Are you a presuppositionalist? — Tom Storm

I don't believe so - I have never heard the term until now haha. Just looking for principles and trying to avoid circularity when possible.

Observations don't prove a scientific theory — Agent Smith

If I understand you correctly, you make a distinct between proof and support; i.e., observations do not prove theories but support the best theory that fit them? In which case, circularity remains: x cannot be used to support or defend x. Any empirical evidence cannot be used to defend the scientific method (whose claim is that empirical evidence can be used to defend a claim).

You also don't seem to understand that it works best when dealing with concrete subjects. It is less reliable when dealing with in the abstract. — ThinkOfOne

Do you have something to support this claim? Also, what is abstract about the argument in the video?

Some years ago, a friend of mine used a similar argument for reincarnation: The verifiable claims of Buddhism are true, therefore it is reasonable to believe that reincarnation is true. Are you buying? Why or why not? — ThinkOfOne

Given the condition that all claims come from the same source and were derived in a similar way (e.g., divine revelation, fortune-telling, etc.), then I am buying. For the same reasons as before: Given that all the verifiable claims are verified to be true, it is reasonable to infer that the source or method is reliable. Note that this is similar to the other discussion occurring in this thread: The scientific method is reliable because it can predict outcomes accurately.

What is your answer to your own questions? Are you saying it is more reasonable to assume all the unverifiable claims to be false?

I'll try, but I admit I am running out of ways to explain myself.
I've numbered the propositions below so it is easier to refer to them.

1. x cannot be used to support x. This is circular reasoning.
2. The scientific method is, simply put, verification by empirical evidence.
3. All success stories resulting from the scientific method are types of empirical evidence.
4. Therefore, these success stories cannot be used to support the scientific method.

To be extra clear: The scientific method is a correct method. It is not inherently circular. What is circular is to attempt to defend the scientific method by appealing to the scientific method. To use an analogy: The laws of logic are true. But we cannot use logic to support the laws of logic.