The reason why you can write parsers with Prolog is because you can cast the problem of determining whether a string belongs to a language or not as a proof, and, in Prolog, express it as a set of Definite Clauses, particularly with the syntactic sugar of Definite Clause Grammars that give you an executable grammar that acts as both acceptor and generator and is equivalent to a left-corner parser.
Now, with that in mind, I'd like to understand how you and the OP reconcile the ability to carry out a formal proof with the inability to do reasoning. How is it not reasoning, if you're doing a proof? If a proof is not reasoning, then what is?
Clearly people write parsers in C and C++ and Pascal and OCAML, etc. What does it mean to come in with "the reason you can write parsers with Prolog..."? I'm not claiming that reason is incorrect, I'm handwaving it away as irrelevant and academic. Like saying that Lisp map() is better than Python map() because Lisp map is based on formal Lambda Calculus and Python map is an inferior imitation for blub programmers. When a programmer maps a function over a list and gets a result, it's a distinction without a difference. When a programmer writes a getchar() peek() and goto state machine parser with no formalism, it works, what difference does the formalism behind the implementation practically make?
Yes maybe the Prolog way means concise code is easier for a human to tell whether the code is a correct expression of the intent, but an LLM won't look at it like that. Whatever the formalism brings, it isn't enough that every parser task is done in Prolog in the last 50 years. Therefore it isn't any particular interest or benefit, except academic.
> both acceptor and generator
Also academically interesting but practically useless due to the combinatorial explosion of "all possible valid grammars" after the utterly basic "aaaaabbbbbbbbbbbb" examples.
> "how you and the OP reconcile the ability to carry out a formal proof with the inability to do reasoning. How is it not reasoning, if you're doing a proof? If a proof is not reasoning, then what is?"
If drawing a painting is art, is it art if a computer pulls up a picture of a painting and shows it on screen? No. If a human coded the proof into a computer, the human is reasoning, the computer isn't. If the computer comes up with the proof, the computer is reasoning. Otherwise you're in a situation where dominos falling over is "doing reasoning" because it can be expressed formally as a chain of connected events where the last one only falls if the whole chain is built properly, and that's absurdum.
> If a human coded the proof into a computer, the human is reasoning, the computer isn't. ... If the computer comes up with the proof, the computer is reasoning.
That is exactly what "formal logic programming" is all about. The machine is coming up with the proof for your query based on the facts/rules given by you. Therefore it is a form of reasoning.
Reasoning (cognitive thinking) is expressed as Arguments (verbal/written premises-to-conclusions) a subset of which are called Proofs (step-by-step valid arguments). Using Formalization techniques we have just pushed some of those proof derivations to a machine.
With Prolog, the proof is carried out by the computer, not a human. A human writes up a theory and a theorem and the computer proves the theorem with respect to the theory. So I ask again, how is carrying out a proof not reasoning?
>> I'm not claiming that reason is incorrect, I'm handwaving it away as irrelevant and academic.
The word "reason" came into this thread with the original comment:
3. LLMs are bad at solving reasoning problems.
4. Prolog is good at solving reasoning problems.
I agree with you. In Prolog "?- 1=1." is reasoning by definition. Then 4. becomes "LLMs should emit Prolog because Prolog is good at executing Prolog code".
I think that's not a useful place to be, so I was trying to head off going there. But now I'll go with you - I agree it IS reasoning - can you please support your case that "executing Prolog code is reasoning" makes Prolog more useful for LLMs to emit than Python?
But I was mainly asking why you say that Prolog's execution is "not reasoning". I don't understand what you mean that '"?- 1=1." is reasoning by definition' and how that ties-in with our discussion about Prolog reasoning or not.
"?- 1=1." is Prolog code. Executing Prolog code is reasoning. Therefore that is reasoning. Q.E.D. This is the point you refused to move on from until I agreed. So I agreed. So we could get back to the interesting topic.
A topic you had no interest in, only interest dragging onto a trangent and grinding it down to make ... what point, exactly? If "executing Prolog code" is reasoning, then what? I say it isn't useful to call it reasoning (in the context of this thread) because it's too broad to be a helpful definition, basically everything is reasoning, and almost nothing is not. When I tried to say in advance that this wouldn't be a useful direction and I didn't want to go here, you said it was " not a great way to have a discussion". And now having dragged me off onto this academic tangent, you dismiss it as "I wasn't interested in that other topic anyway". Annoying.
> "?- 1=1." is Prolog code. Executing Prolog code is reasoning. Therefore that is reasoning. Q.E.D.
This is the dumbest thing i have read yet on HN. You are absolutely clueless about this topic and are merely arguing for argument's sake.
> If "executing Prolog code" is reasoning, then what? I say it isn't useful to call it reasoning (in the context of this thread) because it's too broad to be a helpful definition, basically everything is reasoning, and almost nothing is not.
What does this even mean? It has already been pointed out that Prolog does a specific type of formalized reasoning which is well understood. The fact that there are other formalized models to tackle subdomains of "Commonsense Reasoning" does not detract from the above. That is why folks are trying to marry Prolog (predicate logic) to LLMs (mainly statistical approaches) to get the best of both worlds.
User "YeGoblynQueenne" was being polite in his comments but for some reason you willfully don't want to understand and have come up with ridiculous examples and comments which only reflect badly on you.
You call it the dumbest thing you have ever read, and say that I know nothing - but you agree that it is a correct statement ("Prolog does a specific type of formalized reasoning").
> "What does this even mean?"
For someone who is so eager to call comments dumb, you sure have a lot of not-understanding going on.
1. Someone said "Prolog is good at reasoning problems"
2. I said it isn't any better than other languages.
3. Prolog people jumped on me because Ackchually Technickally everything Prolog does is 'reasoning' hah gotcha!
4. I say that is entirely unrelated to the 'reasoning' in "Prolog is good at reasoning problems". I demonstrate this by reductio ad absurdum - if executing "?- 1=1." is "reasoning" then it's absurd for the person to be saying that definition is a compelling reason to use Prolog, therefore they were not saying that, therefore this whole tangent about whether some formalism is or isn't reasoning by some academic definition is irrelevant to the claim and counter claim.
> "are merely arguing for argument's sake."
Presumably you are arguing for some superior purpose?
The easiest way for you to change my mind is to demonstrate literally anything that is better for an LLM to emit in Prolog than Python - given the condition that LLMs don't have to care about conciseness or expressivity or readability in the same way humans do. For one example I say it would no better for an LLM to solve an Einstein Puzzle one way or the other. The fact that you can't or won't do this, and prefer insults, is not changing my mind nor is it educating me in anything.
You edited your comment without any indication tags which is dishonest. However, my previous response at https://news.ycombinator.com/item?id=45939440 is still valid. This is an addendum to that;
> The easiest way for you to change my mind is to demonstrate literally anything that is better for an LLM to emit in Prolog than Python
I have no interest in trying to change your mind since you simply do not have the first idea about what Prolog is doing vis-a-vis any other non-logic programming language. You have to have some basic knowledge before we can have a meaningful discussion.
However, in my previous comment here https://news.ycombinator.com/item?id=45712934 i link to some usecases from others. In particular; the casestudy from user "bytebach" is noteworthy and explains exactly what you are asking for.
> The fact that you can't or won't do this, and prefer insults, is not changing my mind nor is it educating me in anything.
This is your dishonest edit without notification. I refuse to suffer wilful stupidity and hence retorted in a pointed manner; that was the only way left to get the message across. We had given you enough data/pointers in our detailed comments none of which you seem to have even grasped nor looked into. In a forum like this, if we are to learn from each other, both parties must put forth effort to understand the other side and articulate one's own position clearly. You have failed on both counts in this thread.
No, i did not; do not twist nor misrepresent my words. Your example had nothing whatsoever to do with "Reasoning" and hence i called it dumb.
> you sure have a lot of not-understanding going on.
Your and my comments are there for all to see. Your comments are evidence that you are absolutely clueless on Reasoning, Logic Programming Approaches and Prolog.
> 1. Someone said "Prolog is good at reasoning problems"
Which is True. But it is up to you to present the world-view to Prolog in the appropriate Formal manner.
> 2. I said it isn't any better than other languages.
Which is stupid. This single statement establishes the fact that you know nothing about Logic Programming nor the aspect of Predicate Logic it is based on.
> 3. Prolog people jumped on me because Ackchually Technickally everything Prolog does is 'reasoning' hah gotcha!
Which is True and not a "gotcha". You have no definite understanding of what the word "Reasoning" means in the context of Prolog. We have explained concepts and pointed you to papers none of which you are interested in studying nor understanding.
> 4. I say that is entirely unrelated to the 'reasoning' in "Prolog is good at reasoning problems". I demonstrate this by reductio ad absurdum - if executing "?- 1=1." is "reasoning" then it's absurd for the person to be saying that definition is a compelling reason to use Prolog, therefore they were not saying that, therefore this whole tangent about whether some formalism is or isn't reasoning by some academic definition is irrelevant to the claim and counter claim.
What does this even mean? This is just nonsense verbiage.
> Presumably you are arguing for some superior purpose?
Yes. I am testing my understanding of Predicate Logic/Logic Programming/Prolog against others. Also whether others have come up with better ways of application in this era of LLMs i.e. what are the different ways to use Prolog with LLMs today?.
I initially thought you were probably wanting a philosophical discussion of what "Reasoning" means and hence pointed to some relevant articles/papers but i am now convinced you have no clue about this entire subject and are really making up stuff as you go.
You are wasting everybody's time, testing their patience and coming across as totally ignorant on this domain.
I'm sorry you find my contribution to the discussion annoying, but how should I feel if you just "agree" with me as a way to get me to stop arguing?
But I think your annoyance may be caused by misunderstanding my argument. For example:
>> If "executing Prolog code" is reasoning, then what? I say it isn't useful to call it reasoning (in the context of this thread) because it's too broad to be a helpful definition, basically everything is reasoning, and almost nothing is not.
Everything is not reasoning, nor is executing any code reasoning, but "executing Prolog code" is, because executing Prolog code is a special case of executing code. The reason for that is that Prolog's interpreter is an automated theorem prover, therefore executing Prolog code is carrying out a proof; in an entirely literal and practical sense, and not in any theoretical or abstract sense. And it is very hard to see how carrying out a proof automatically is "not reasoning".
I made this point in my first comment under yours, here:
The same clearly does not apply to Python, because its interpreter is not an automated theorem prover; it doesn't apply to javascript because its interpreter is not an automated theorem prover; it doesn't apply to C because its compiler is not an automated theorem prover; and so on, and so forth. Executing code in any of those languages is not reasoning, except in the most abstract and, well, academic, sense, e.g. in the context of the Curry-Howard correspondence. But not in the practical, down-to-brass-tacks way it is in Prolog. Calling what Prolog does reasoning is not a definition of reasoning that's too broad to be useful, as you say. On the contrary, it's a very precise definition of reasoning that applies to Prolog but not to most other programming languages.
I think you misunderstand this argument and as a consequence fail to engage with it and then dismiss it as irrelevant because you misunderstand it. I think you should really try to understand it, because it's obvious you have some strong views on Prolog which are not correct, and you might have the chance to correct them.
I absolutely have an interest in any claim that generating Prolog code with LLMs will fix LLMs' inability to reason. Prolog is a major part of my programming work and research.
> "how should I feel if you just "agree" with me as a way to get me to stop arguing?"
Triumphant? Victorious? magnificent, successful, proud, powerful, insert any adjective which applies to a situation where someone wanted something, and then got it.
> "And it is very hard to see how carrying out a proof automatically is "not reasoning. The same clearly does not apply to Python, because its interpreter is not an automated theorem prover; it doesn't apply to javascript because its interpreter is not an automated theorem prover"
And that does not stop Python or Javascript from being used to find solutions to e.g. an Einstein Puzzle, something a human might call "a reasoning problem". This means Prolog 'doing reasoning' must not be the thing which solves the 'reasoning problem', something else must be doing that because non-reasoning systems can do it too.
If Prolog 'doing reasoning' meant it could solve 'reasoning problems' that no other programming language could, that would be a strong reason to use Prolog, but that is not something you or the other 'reasoning' commenters have claimed or offered examples of. Clearly the word 'reasoning' has different definitions in the different sentences and that is important here because I am responding to one and youall on the other.
If 'doing reasoning' is not the thing which makes it useful for 'solving reasoning problems' - if that neither compels one to use Prolog when working to 'solve a reasoning problem', nor convinces one to avoid other languages - if the definition does not influence one's decision in any way - it's very hard to see how it is the relevant version of 'reasoning' to focus on, and what point is trying to be made by this insistence on focusing on it, except academic one-upping.
>> And that does not stop Python or Javascript from being used to find solutions to e.g. an Einstein Puzzle, something a human might call "a reasoning problem". This means Prolog 'doing reasoning' must not be the thing which solves the 'reasoning problem', something else must be doing that because non-reasoning systems can do it too.
To solve an Einstein puzzle in Python et al. you have to code 1) a definition of the problem and 2) a solution that you come up with. In Prolog you only have to code a definition of the problem and then executing the definition gets to the solution.
Other languages indeed can solve problems that Prolog can, but a human programmer must code the solution, while Prolog comes built-in with a universal problem solver, SLD-Resolution, that can solve any problem a human programmer can pose to it.
I looked around for an example of this with real code and found this SO thread on programmatically solving a Zebra puzzle (same as the Einstein puzzle):
There are a few proposed solutions in Python, and in Prolog. The Python solutions pull-in constraint solving libraries, encode the problem constraints and then use for-loops to iterate over the set of solutions that respect the constraints.
The Prolog solutions do not pull in any libraries and do not iterate. They declare the constraints of the problem and then execute the constraints, letting the Prolog interpreter find a solution that satisfies them.
So the difference is that Prolog can solve the problem on its own, while Python can solve it only if you hand-code the solution, which includes importing a constraint solver. Constraint solving is of course a form of reasoning, and that's how you can get Python to do reasoning: by implementing a reasoning algorithm. In Prolog you don't need to do that, because SLD-Resolution is a universal problem solver that can be applied to constraint problems, like any other problem. This is not an academic matter, as you insist that it is; it is a practical matter, of knowing how to code a universal problem solver and getting it to run on real-world hardware.
I say that solving constraints is a form of reasoning. You won't find anyone to disagree with this in the CS and symbolic AI community. While you also won't find an agreed-upon, formal definition of "reasoning", we don't need one because we've been studying reasoning since the time of Aristotle and his "Syllogisms" (literally, "Reasonings" in Greek). In the same way you won't really find an agreed-upon definition of "mathematics", but we don't need one because we've been studying maths since the time of the ancient Babylonians (at least; my memory is hazy).
You argue that what Prolog does isn't reasoning, but that's a very niche view. Not that this means you're wrong, but one reason I insist with this discussion is that your view is so unorthodox. If you're right, I'd like to know, so I can understand where I was wrong. But so far I still only see a misunderstanding of Prolog and a continued unwillingness to engage with the argument that Prolog does reasoning because it has an automated theorem prover as an interpreter.
Note that the Prolog solutions in the SO thread are a bit over-engineered for my tastes. The one in the link below is much more straightforward although it's for a simplified version of the problem. Still, it shows what I mean that you only need to define the problem and then the interpreter figures out how to solve it.
Now, with that in mind, I'd like to understand how you and the OP reconcile the ability to carry out a formal proof with the inability to do reasoning. How is it not reasoning, if you're doing a proof? If a proof is not reasoning, then what is?