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The metaphysical presuppositions of formal logic

edwardfeser.blogspot.com

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Re: The metaphysical presuppositions of formal logic

#81

Post by ukj »

the_af wrote: post #76
ukj wrote: post #71

Earlier quoted context omitted.

>There are many ways of comparing functions. Indeed. I pointed this out and provided a link in my first post on this thread. >You don't see them because they are implicit! The fact that my function takes no arguments is implicit in the specification of my function. I know because I said the English sentence "The function that I have in mind takes no arguments". You seem to be suggesting that I don't know what functio…

Your function does take implicit arguments. There's no way your Ruby function can return the current time ("now") without external dependencies that supply that time. If you want to argue otherwise, you must provide this hypothetical implementation that complies with your specs. I'm telling you that your function effectively can't exist as you describe it. In order for your function to work it requires an implicit ar…

You are asking me to provide the hypothetical implementation for a real-world function?

I don't know how to respond to this. Just observe the thing I am showing you. THAT is what I am talking about. It's right before your eyes - I took it from my head and made it real.

>If you want to argue that

I DON'T want to argue! All I am doing here is expressing myself - you are the one jumping down my throat.

This is me telling you that I am not interested in any social game of figuring out "who is right or who is wrong". If that's the game you are playing - I am happy to terminate the interaction.

What I mean by f() != f() in the abstract is precisely that Ruby program in the concrete. Nothing more - nothing less.

There is no room for "right" and "wrong" here. Those are moral judgments and I've committed no moral violation of any sort.

Re: The metaphysical presuppositions of formal logic

#82

Post by Cybotron5000 »

alentist wrote: post #78
Cybotron5000 wrote: post #77

Earlier quoted context omitted.

What do you consider to be my assumptions? As I said in the comment below, I am not attacking the guy personally (that’s what ad hominem means) - I’m sure he may be perfectly lovely and if he is genuine in his pursuits then I genuinely wish him (and you) all the best in life…

> What, pray tell, do you consider to be my assumptions? I don't know, because you didn't engage with the content of the article at all. You merely casted nasty aspersions on its author. > I am not attacking the guy personally Yes, you are. he seems to specialize in a specious species of polemic and obfuscation designed solely to justify and promulgate his political and religious views. If it lends a sense of purpose…

Perhaps you’re right and I was overly harsh or critical of him personally. All I am trying to say, crudely put, is that it seems to me that the author has started from his prior positions and then constructed an argument that reinforces them. That’s fine by me (if he is honest about it), but I hope you can see it is hard to stomach if you don’t agree or can’t see the proof of those prior positions. Specious = “…plausible but false; based on pretense; deceptively pleasing: ‘His incorrect conclusion arose from specious reasoning.’”. For example, a statement like: “…an analysis that simply fails to capture what Aquinas is talking about is hardly rigorous…” (sorry taking that out of context) seems bizarre to me when I consider (the little I know of) the history of philosophical thought since Aquinas… I apologize if I have offended you or the author- that was not my intention - perhaps I am merely showing my ignorance…

Re: The metaphysical presuppositions of formal logic

#83

Post by the_af »

ukj wrote: post #81
the_af wrote: post #76

Earlier quoted context omitted.

Your function does take implicit arguments. There's no way your Ruby function can return the current time ("now") without external dependencies that supply that time. If you want to argue otherwise, you must provide this hypothetical implementation that complies with your specs. I'm telling you that your function effectively can't exist as you describe it. In order for your function to work it requires an implicit ar…

You are asking me to provide the hypothetical implementation for a real-world function? I don't know how to respond to this. Just observe the thing I am showing you. THAT is what I am talking about. It's right before your eyes - I took it from my head and made it real. >If you want to argue that I DON'T want to argue! All I am doing here is expressing myself - you are the one jumping down my throat. This is me tellin…

I'm asking you to provide the actual implementation of your hypothetical function now().

I don't need to know the implementation of the real function Time.now from Ruby because, without looking at its source code, I can tell you that it has implicit arguments.

How can I tell this? Because it's impossible for your Ruby program to tell the time without some kind of interaction with an external source (be it the computer clock, the internet or whatever); this source is your implicit parameter and it's why two invocations of your function don't return the same value. It is impossible for your function not to have this source of time, either implicitly or explicitly.

If you disagree, then please explain how your function tells time.

Re: The metaphysical presuppositions of formal logic

#84

Post by ImprobableTruth »

creata wrote: post #80
practal wrote: post #5

It's important to sometimes step back and think about whether what you are doing actually makes sense. There are some assumptions about how formal logic is done in ITP (interactive theorem proving) systems that should be challenged. Here is my opinion about that: https://doi.org/10.47757/practal.1

> Instead, coercions are used to emulate some of the advantages of subtyping. Maybe I missed it in the article, but what does subtyping give you that coercions don't?

While I'm not sure it's impossible (though if it's possible I doubt it would be pretty or non-fragile), I've at least never seen anybody emulate generic intersection/union types using coercions. Dependent intersections like in Cedille are definitely impossible.

Re: The metaphysical presuppositions of formal logic

#85

Post by [deleted] »

Cybotron5000 wrote: post #82
alentist wrote: post #78

Earlier quoted context omitted.

> What, pray tell, do you consider to be my assumptions? I don't know, because you didn't engage with the content of the article at all. You merely casted nasty aspersions on its author. > I am not attacking the guy personally Yes, you are. he seems to specialize in a specious species of polemic and obfuscation designed solely to justify and promulgate his political and religious views. If it lends a sense of purpose…

Perhaps you’re right and I was overly harsh or critical of him personally. All I am trying to say, crudely put, is that it seems to me that the author has started from his prior positions and then constructed an argument that reinforces them. That’s fine by me (if he is honest about it), but I hope you can see it is hard to stomach if you don’t agree or can’t see the proof of those prior positions. Specious = “…plaus…

[deleted]

Re: The metaphysical presuppositions of formal logic

#86

Post by alentist »

Cybotron5000 wrote: post #82
alentist wrote: post #78

Earlier quoted context omitted.

> What, pray tell, do you consider to be my assumptions? I don't know, because you didn't engage with the content of the article at all. You merely casted nasty aspersions on its author. > I am not attacking the guy personally Yes, you are. he seems to specialize in a specious species of polemic and obfuscation designed solely to justify and promulgate his political and religious views. If it lends a sense of purpose…

Perhaps you’re right and I was overly harsh or critical of him personally. All I am trying to say, crudely put, is that it seems to me that the author has started from his prior positions and then constructed an argument that reinforces them. That’s fine by me (if he is honest about it), but I hope you can see it is hard to stomach if you don’t agree or can’t see the proof of those prior positions. Specious = “…plaus…

You're casting more vague aspersions.

> the author has started from his prior positions and then constructed an argument that reinforces them

There are two ways to interpret this:

1. You're accusing the author of making an argument that is circular. If so, describe the argument, including its premises and conclusion, and specify which premise is the conclusion.

2. You're merely attacking the author for arguing their position. Hardly objectionable and also a red herring, since the soundness of an argument is independent of the author's "prior positions".

Furthermore, I see nothing controversial about the statement you quoted. It is indisputably true, and would be true for any other author.

Re: The metaphysical presuppositions of formal logic

#87

Post by ukj »

the_af wrote: post #79
ukj wrote: post #69

Earlier quoted context omitted.

You know what the state of the universe is when you do logic? Tell us more! I didn't believe in omniscience until now. Time.now(t1) and Time.now(t2) is meaningless in this context because t1 and t2 are unbound variables. What are you passing to your function? Where is it coming from? My function says you are overlooking something. [1] pry(main)> Time.now(t1) NameError: undefined local variable or method `t1' for main…

If you're familiar with the literature of programming languages, you'll see references to the "world" or the "universe" all the time. That's the kind of universe we mean in this discussion, not the one Carl Sagan talked about. As for the rest: please provide the implementation of your Time.now function and I'll tell you its implicit parameters. If you're not talking about an actual function that can be run by a compu…

>please provide the implementation of your Time.now function and I'll tell you its implicit parameters.

You are missing the point about extensional and intensional properties of functions.

If you want to look "inside" my Time.now function then maybe you should also look "inside" your equality function and find its implicit parameters?

Here's some Python boiler plate - implement equality and make the assertions pass.

  def f():
    return 1

  def equal(x,y): 
    # Implement equality

  assert not equal(1,2)
  assert equal(1,1)
  assert equal(f, f)
>If you're not talking about an actual function that can be run by a computer

As far as I can tell you are not talking about such a function either when you speak about equality, but I'll reserve judgment until you produce an implementation.

>I'm not interested in hypothetical functions tautologically defined not to be equal to themselves.

OK, but you are interested in hypothetical functions tautologically defined to be equal to themselves.

That's perfectly fine - we are interested in different tautologies.

You want to say equal(f,f) is true.

I want to say not equal(f,f) is true.

We want to say different things.

Re: The metaphysical presuppositions of formal logic

#88

Post by ukj »

the_af wrote: post #83
ukj wrote: post #81

Earlier quoted context omitted.

You are asking me to provide the hypothetical implementation for a real-world function? I don't know how to respond to this. Just observe the thing I am showing you. THAT is what I am talking about. It's right before your eyes - I took it from my head and made it real. >If you want to argue that I DON'T want to argue! All I am doing here is expressing myself - you are the one jumping down my throat. This is me tellin…

I'm asking you to provide the actual implementation of your hypothetical function now() . I don't need to know the implementation of the real function Time.now from Ruby because, without looking at its source code, I can tell you that it has implicit arguments. How can I tell this? Because it's impossible for your Ruby program to tell the time without some kind of interaction with an external source (be it the comput…

And I am asking you to provide the actual implementation of your hypothetical function equal().

I don't need to know the implementation of the real function == from any programming language because, without looking at any source code I can tell you that it has implicit arguments: a tautology.

If you disagree, then please explain how equality functions.

Re: The metaphysical presuppositions of formal logic

#89

Post by skissane »

> This has some notoriously odd results (known as the “paradoxes of material implication”)

> You’ll still get weird results (known as the “paradoxes of strict implication”)

This is obviously building up to the concept of relevance logic (called "relevant logic" in the UK and Australia) – https://plato.stanford.edu/entries/logic-relevance/ – and no doubt Feser knows about it, but isn't taking the reader there. It seems to me an odd omission.

A lot of his argument is actually against classical logic, not formal logic. Many philosophers and logicians agree that classical formal logic is deeply flawed, and have proposed various non-classical formal logics in response (relevance logic, constructivist/intuitionistic logic, paraconsistent logic, among others). But in this blog post he doesn't interact with or mention any of that work.

> To show that the eternalist conclusion really follows, and does not merely falsely appear to do so, would require independent metaphysical argumentation

I've never understood how Feser manages to believe in both presentism and divine eternity. In my mind they are mutually exclusive propositions. Atheism and process theism / open theism both go well with presentism. But the eternal God of classical theism, who knows all of time as one single moment, seems to me to have an eternalist approach to time as an inevitable consequence.

Re: The metaphysical presuppositions of formal logic

#90

Post by skissane »

Cybotron5000 wrote: post #70
Cybotron5000 wrote: post #64

Earlier quoted context omitted.

I think that sometimes being overly opinionated and incapable of changing your mind is potentially harmful to others, yes… Is it not potentially dangerous to advocate for various political realities based solely on unexamined/individual opinion-based constructs? Maybe I am wrong, though… I’m curious what you think of the ideas in this article?: https://aphilosopher.drmcl.com/2007/08/26/is-philosophy-just...

…and yes I think that challenging one’s suppositions ought to be the first task of any aspiring philosopher. Isn’t that the whole idea?

Having read a few philosophers, I don't really see any fundamental difference between Feser's approach and those of other philosophers. All philosophers have their positions and try to construct arguments to support those constructions. Feser's positions are traditional Roman Catholic positions, but your average atheist philosopher (such as Graham Oppy or J. L. Mackie) is doing the same basic thing.

I feel like your expectations for how philosophers ought to behave aren't based on any significant familiarity with the work of actual philosophers, just your suppositions about how philosophy ought to be done.

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