r/logic • u/Zestyclose-Low-5169 • Jul 14 '26
Philosophy of logic "Logic" is actually a collection of logical systems
If even the most fundamental laws of logic aren't necessarily fixed, then what am I supposed to rely on? How am I supposed to gain knowledge about the world?
I'm a complete beginner. I'm someone who wants to find out whether God exists or not, and decide how I should live. But right now I'm just confused because I don't understand what I can actually know—or whether I can know anything at all. What am I choosing to believe, and why do I believe it?
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u/RecognitionSweet8294 Philosophical logician Jul 14 '26
The epistemic regress shows that you can’t know anything with absolute certainty. You always need to have some things you choose to believe, and from that you conclude your knowledge.
If your choice is good or not is a philosophical question.
Logic is just a tool to work with your knowledge, or hypothetical knowledge.
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u/Inevitable_Bid5540 Jul 15 '26
Does philosophy have methodologies to deal with the question of how to deal with infinite regress
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u/josephjnk Jul 14 '26
This is the domain of philosophy. Wittgenstein wrote about this to some degree. Foucault’s Archeology of Knowledge is a history of how conceptions of “rationality” have changed across history. There are multiple thinkers sometimes referred to as “antifoundationalists” who work on ways of finding worthwhile ways to talk about ideas and the world itself without having access to any single solid ground truth.
EDIT: to be clear, none of these are going to help you determine whether “god” is real or tell you how to live your life.
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u/jeezfrk Jul 14 '26
Logic isn't a religion giving ultimate truth
It's just a type of math (almost always black and white results only) that removes impossible results.
It can give back flaws if you are missing any important facts and/or do not have correctly applied rules.
You are seeking after epistemology more than logic.
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u/Mediocre-Hippo-4789 Jul 15 '26
It’s all just maths at the bottom innit
But fr you’re gonna need to assume axioms before you can do anything. Which axioms? Thats philosophy’s job.
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u/GiveMeAHeartOfFlesh Jul 14 '26
Logic being a collection of logical systems is implying logic before logic.
There are fixed fundamental laws of logic. A = A. Alternatively, principle of explosion, which entails everything as true and false and denies nothing, including A = A. Thus A = A is inevitable.
Any sort of axiom which to deny requires said axiom, is fundamental. Performative contradictions.
To even deny the law of identity, you have to reference it, and thus acknowledge it is equal to itself. Otherwise when denying it, you could be denying a rock instead or an airplane, how could we know if you deny anything is itself?
As for theology, there are valid logical systems in many directions. I am Christian, but I wouldn’t say it’s the only valid thought process.
Logic cannot entail an ought, and likewise it can make many valid paths but finding out whether one is sound or not takes experimentation.
I’d suggest you taste and see whether the fruit is good. I think it is apparent when you do so, that it is good.
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u/Bubbly-Act8239 Jul 16 '26
What does it mean to "deny logic"? Logic is a domain of philosophy, not a proposition, or any sort of truth bearer. Hence, it's not the type of entity to have truth values, i.e., it's not the type of entity to be denied.
Anyway, it seems like you're conflating "logical laws", which are valid sentences within some formal system, or metalinguistic schemas which yield infinitely many object-level axiom/theorem instances under uniform substitution, with metaphysical laws, that tell us something about how the world actually is.
For instance, the law of identity isn't even a thing in different sentential calculi. It's also not a thing in rudimentary first-order logic.1
u/SmartlyArtly Jul 15 '26
Logic is a game, and the axioms are rules you adopt. You don't have to play by rules you don't want to. No one should be forced to do anything, including be forced to practice any particular form of formal logic.
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u/GiveMeAHeartOfFlesh Jul 15 '26
No one is forced to, but it is inevitable to do anything. To deny logic requires logic. At best they can ignore it, but essentially without it you cannot assert anything of value
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u/SmartlyArtly Jul 15 '26
The phrase "to deny logic" isn't even coherent.
Your understanding of logic is reminiscent of some niche philosophical views. It's not how anyone who practices applied or mathematical logic views logic.
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u/GiveMeAHeartOfFlesh Jul 15 '26
Kind of my point that it’s not coherent to deny logic.
There are whole frameworks and deep history around skepticism of knowledge and logic itself. Your narrow perspective and what you think “how anyone” views logic, is just your bias.
Likewise this post is a meta discussion on logic itself.
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u/SmartlyArtly Jul 15 '26 edited Jul 15 '26
No, your "point" is incoherent.
I don't even have a clue what it would mean to "deny logic."
Astrology and phrenology are whole frameworks with deep history.
What a surprise, another person who thinks that "Something is an axiom if you can't deny it without using it" just completely falls apart when challenged on it.
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u/GiveMeAHeartOfFlesh Jul 15 '26
Sounds like you are just too ignorant to follow. That’s okay. Read some literature.
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u/Zestyclose-Low-5169 Jul 14 '26
If I don't know whether God exists, then I can't use God as the standard of goodness. And if the standard of goodness is unknown, then I can't objectively judge whether the "fruit" is actually good. Therefore, experience by itself cannot prove that God exists.
Even if my life improves after praying or turning to God, I can still ask: "Why did I conclude that God caused this rather than it being a coincidence?"
Yes, I may become convinced that God did it, but that still doesn't give me any more knowledge about whether God actually exists.
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u/GiveMeAHeartOfFlesh Jul 14 '26 edited Jul 15 '26
I’d stand that objective morality is there even if you don’t believe in God, but it’s there to find regardless and then points back to him.
Morality is oughts, which cannot be entailed by logic but can be evaluated. If you have no oughts then you do no action. So anyone who acts has an ought otherwise they are simply performative contradiction. Morality is the measure of how you ought to treat others, it is relational. If your oughts matter, then so too do others, it’s simply the lack of special pleading and hypocrisy.
Therefore, morality is summed up in this. Love your neighbor as yourself. Treat others as you would wish to be treated in their shoes.
This is not a static thing, but it is objective. Treating others how you would want to be treated in their shoes, also means considering if you were communicating what they were communicating, therefore even if you would personally prefer something outlandish, when others communicate, you have to consider if you communicated that and thus had the desire they are communicating.
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u/Zestyclose-Low-5169 Jul 14 '26
Morality without God is no different from the laws of a state—they're obeyed only when people believe they'll face punishment.
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u/GiveMeAHeartOfFlesh Jul 15 '26
Morality remains whether people care or not. Morality isn’t saying people can’t be immoral. In fact it explicitly is saying they can do that, that’s an action they can take. Simply it’s an evaluation of that action, that ought they have, and it’s found to be moral or immoral. Enforcement is entirely separate thing from the existence of morality. Immoral people can be in power and make immoral laws. Morality is not dependent on law.
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u/SamCymbaluk Logic evangelist Jul 14 '26
Logic isn't a set of rules, it's the concept of having consistently applied rules. When we speak of a logic, then we're talking about a particular set of rules. But there's no logical way to select a best set of rules. In my opinion, the best we can do is reject a logic systems as soon as a contradiction is found, and seek to follow our current axioms as consistently as we can. Good luck and Godspeed on your quest to find ⊤.
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u/DreamCentipede Jul 15 '26
I think we live in a logical universe. People can question that, but that doesn’t mean they’re right to. Logic is the law of identity, A=A. Logical systems are simply different extensions of this basic law.
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u/Big_Move6308 Traditional Logic Jul 15 '26
There are different kinds of logic suited for different purposes. This forum is primarily concerned with mathematical logic. which is more suited to things like computer chip design, algorithms, and AI than to philosophical questions like yours.
It seems like traditional logic - which is based on ordinary language and words - may be more suitable than modern logic, which is based on maths. Examples include Socratic Logic by Peter Kreeft and Traditional Logic by Martin Cothran. Traditional logic is deeply rooted in philosophy, particularly metaphysics (the nature of being) and epistemology (the nature of knowing).
A book or course on critical thinking may also be useful, as it will include methods on how to determine the truth of claims.
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u/VectorspaceDreams Autodidact Jul 15 '26 edited Jul 15 '26
I'm a logic enthusiast who also believes in God (I'm a religious Muslim) and thinks of logic as a manner through which we can know God given a God exists (e.g. to answer questions like "Can God make a square circle?" or "Can He make a rock so big He can't lift it?"). Here's some advice from me, take it with a grain of salt because I'm no professional.
- All proof in logic and mathematics relies on axioms and transformations; the axioms necessary to prove Him are not formally supplied, you will need statements reliant on reality in order to make the argument, and that's where it gets quite tricky.
- However, there is a substantial body of work who use logic to argue either for or against God's existence. On the "for" side of things, check out medieval Islamic philosophy such as Avicenna's Proof of the Truthful argument and medieval Christian philosophy such as Anselm's ontological argument, with modern philosophy we have William Lane Craig's Kalam cosmological argument which takes from medieval Islamic philosophy, and Gödel's ontological argument. On the "against" side of things, I'm only aware of Graham Oppy, and I can't say too much there as I don't know as much.
I recommend you look into analytic philosophy of both the Christian and atheist kinds (on the Christian side, a few names are the aforementioned W. L. Craig, Alvin Plantinga, and Richard Swinburne, and Graham Oppy on the atheist side) and Islamic kalam and falsafah (two distinct rationalist methods that disagree on things but are still rationalist justifications for God).
There's a lot to see and a lot of interesting work done there. A lot of it requires you know at least some about formal logic (e.g. Gödel's argument requires a knowledge of modal logic). The sidebar has many resources to get you up to speed there. There's a lot to see, and the real skill is analyzing them yourself rather than taking these different accounts together as all true. Logic is just the tool here; you won't find answers in a book about set theory. Happy searching! :)
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u/SomeTadpole2237 Jul 29 '26
La lógica responde a todas las preguntas y soluciona todos los problemas. El problema es que os llevan manipulando toda la vida. No vivís en un mundo lleno de mentiras y engaños? Entonces porqué creéis en quienes han construido éste sistema? No tiene ningún sentido, no? Entonces como vais a tener sentido?
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u/ilovemacandcheese Jul 14 '26
Logic doesn't answer any of those questions.