Philosophy Now Forum

Hello everybody. I'm taking a philosophy course in college right now, Symbolic Logic, and I just don't understand the need for it. I'm all for learning for learning's sake, but this is starting to take the place of trigonometry as the most useless thing I've been forced to learn. Ok, not all of it was bad, but right now we are doing the rules of derivations. I was wondering if anyone could shed light on the use of any of this, because to me it seems completely irrelevant to anything; a system on a system that has no use. Thank you for any help!

It is true that the arguments that get used as examples in courses tend to be trivial ones. You can see straightaway whether the argument is valid or not. But:

(i) there are more complicated arguments around, and once you learn how to analyse the easy ones, you will be able to analyse the more complex ones. There is an analogy with engineers who handle all the complicated equations that they need in order to build bridges that stay up, or whatever. They are applying techniques that they first learnt with really easy equations, like 3x + 7 = 43;

(ii) philosophical arguments are often expressed in continuous prose, and generally first occur to their authors in that form. One of the best ways to test them for validity, and to reveal unspoken assumptions, is to translate them into the language of symbolic logic. Again, the techniques you need in order to do that are the ones that you learn by doing simple examples;

(iii) if you grasp how logical systems work, you can then go on to grasp important results about logical systems, for example soundness results (if you can prove it, then it must be true), completeness results (if it must be true, then you can prove it) and, most interestingly, incompleteness results (in some systems, you cannot prove things even though they must be true). These are rough and ready statements of soundness, completeness and incompleteness. The true significance of these results can only be grasped if you have a bit of symbolic logic.

Richard Baron wrote:It is true that the arguments that get used as examples in courses tend to be trivial ones. You can see straightaway whether the argument is valid or not. But:

(i) there are more complicated arguments around, and once you learn how to analyse the easy ones, you will be able to analyse the more complex ones. There is an analogy with engineers who handle all the complicated equations that they need in order to build bridges that stay up, or whatever. They are applying techniques that they first learnt with really easy equations, like 3x + 7 = 43;

(ii) philosophical arguments are often expressed in continuous prose, and generally first occur to their authors in that form. One of the best ways to test them for validity, and to reveal unspoken assumptions, is to translate them into the language of symbolic logic. Again, the techniques you need in order to do that are the ones that you learn by doing simple examples;

(iii) if you grasp how logical systems work, you can then go on to grasp important results about logical systems, for example soundness results (if you can prove it, then it must be true), completeness results (if it must be true, then you can prove it) and, most interestingly, incompleteness results (in some systems, you cannot prove things even though they must be true). These are rough and ready statements of soundness, completeness and incompleteness. The true significance of these results can only be grasped if you have a bit of symbolic logic.

Ohh ok. I can definitely understand how what we learned at the beginning of the class was relevant, it was just these derivations that I didn't understand the need. Thanks for such a thorough response, much better than what I got from my teacher, which was, "because it's required." And to think of why I would be transferring after this semester?

I still think trigonometry was completely pointless, but that's a different issue.

ch33z3 wrote:
Hello everybody.

I'm taking a philosophy course in college right now, Symbolic Logic, and I just don't understand the need for it.

I'm all for learning for learning's sake, but this is starting to take the place of trigonometry as the most useless thing I've been forced to learn.

Ok, not all of it was bad, but right now we are doing the rules of derivations. I was wondering if anyone could shed light on the use of any of this, because to me it seems completely irrelevant to anything; a system on a system that has no use.

Thank you for any help!

I can give a long reply but I shall keep it short and simple:

You are being brainwashed.

99% of so-called education is more harmful to humans then it is beneficial. Your course is one example.

Your mind is too powerful and it needs to be enslaved at all costs. And you can see the costs they will pay to get your mind.

Think about it. They have to keep you dumb and docile.

You are being told to accept usefulness of vanity.

God !!

Get out of man before they turn you into a zombie.

Ray has no need for symbolic logic.

Quite right, abandon the study of logic as applied to reason and thought. Instead find comfort in authority and faith, no logic or reason needed just obedience.

I wasn't trying to say that it was all useless information, which I believe Ray and Arising took it as.

What I was wondering was, what would be the need for such a question as the one below, in any other place but in a symbolic logic class.

DvE
(DvF)[horsehoe]G
~G[horseshoe]~E
______________
G
?

I couldn't figure out how to type the horseshoe or if-then variable, so as you can see, I just typed it out.

Is symbolic logic anything more than a shorthand for philosophical argumentation?

My undergraduate philosophy degree concentrated on showing us different kinds of criticism and argument, ranging from the analytic (logic, language) to the empirical (scientific) to 20th century methods such as psychoanalysis, discourse theory and deconstruction (with no emphasis being placed on any one in particular).

I then moved to a different university to study for an MA and discovered that their undergraduate philosophy students were all required to study logic during their entire degree. This surprised me. I would have understood logic as an optional component of a degree (or perhaps as a core class in the first year and optional beyond that); however, I do not think it necessary to have a thorough understanding of logic in order to either study or do philosophy (although many university philosophy departments) would probably disagree.

I am now studying for a doctoral degree, having previously completed a BA and two MAs; all of these were in philosophy or a related subject (the second MA was social and political thought) and none of them required me to have any grasp of symbolic logic.

I would argue that it is important to understand the principles of philosophical argumentation; I also admit that this will probably include logic to some degree. However, it is possible to think critically without thinking in terms of logic. The emphasis placed on logic in undergraduate philosophy degrees is detrimental to a wider understanding of what philosophical criticism can do.

That being said, if we want to criticise something properly then we need to know it, so any thorough criticism of logic (something which I, here, do not intend) requires a study of logic in order to happen. Perhaps this is a reason to study it; not as knowledge for the sake of knowledge but as a particular viewpoint on argumentation and philosophy which is incomplete and one-sided.

andrewmason wrote:thanks for detailed answer it update many people like me who are interested with philosophy. The person has got the answer. Nice contribution on your behalf.

Why are spambots illiterate? Does it make them harder for automatic filters to spot?

You have to love the fact that Christian resellers have discovered the power of spambots though.

John wrote:You have to love the fact that Christian resellers have discovered the power of spambots though.

I suspect we view many Christian apologists as spam bots at the best of times

Hi ch33z3, I believe Arising was ironically satirising Ray's viewpoint.

I agree with ala1993 that symbolic logic is a shorthand for philosophical argumentation. You can easily do sound reasoning without the shorthand, but translating it into shorthand can save time. However, any translation can result in the loss of fundamental meaning, and thorough examinations are best done without it, in my opinion. It is more than a few times that I have met people who have followed what they perceived to be the laws of logic but have taken a wrong turning, such as by taking 'it is not that I dislike it' to be equivalent to 'I like it'.

In my philosophical education there seemed to be a solid emphasis on these logical rules, but little explanation of their actual nature, precisely why they are true, and even less room for questioning them. The litmus test of mathematics is its internal coherency, and so too is it for logic, but the internal coherency of mathematics has to follow from the fundamental nature of a number system. In logic there is no such fundamental basis, there is truly only the ever-shifting sands of human perception and insight. Since we all follow different rational axioms the system that arises is different. But, people do love to delude themselves into assuming a commonality.

Symbolic logic is useful, but it is not the paragon some make it out to be, and nor is it in any way a litmus test of any philosophical notion, and nor is it a guide. It is an easier way of saying something that would otherwise take a long time. When a disagreement arises then fundamentally you have to jump out of the shorthand and back into real speech, it is no good just repeating that something is logically flawed if the other person disagrees with you. As such, overall, it doesn't save all that much time, other than by making some pompous asses declare themself the winner of an argument due to the self-assurance that comes with believing themselves to be backed by an objective and coherent system, when in truth it is merely the backing of their own mode of thinking.

Hello,

I am new to this forum - interested in the replies to ch33z3. I teach Introductory Logic and have never met a student whose "own mode of thinking" bore any resemblance to symbolic logic, or even basic Aristotelian logic.

I agree with Psychonaut that sound argument will not persuade someone who disagrees with you. Sound (logical) arguments only persuade folk who are trained in Logic. But knowledge of logic serves as a form of self defence against all kinds of rhetoric, not only in Philosophy. It has immense benefits in everyday life.

Philinquirer wrote:I teach Introductory Logic and have never met a student whose "own mode of thinking" bore any resemblance to symbolic logic, or even basic Aristotelian logic.

Oh dear, as bad as that? My experience has been a bit better. When you are dealing with arguments that one might actually need in real life, with true premises and useful conclusions, I find that students can get the point. Some of them have a Monsieur Jourdain moment, and realise that they have been thinking logically all their lives.

Indeed, one would expect that. If you do not follow at least basic logic, including things like modus ponens and the rule that you can infer p & q from p, q, life is likely to be quite difficult. But I do not think one could push the consequences of practical need very far. It does not, for example, matter to most of us whether we adopt modal logic S4 or S5, or indeed whether it has ever occurred to us that there are different systems of modal logic.

Students are more likely to come unstuck, in my experience, when you ask them to take seriously a definition of validity that allows you to infer anything from a contradiction, and that allows you to infer a tautology from anything. They have a natural expectation that the premises should do some work and should be relevant to the conclusion - things that are true of the arguments that we find useful in real life.

Hi Richard,
I would not say it is bad - just that it is the case that students' own mode of thinking is different. For example, as you say,

"Students ........ have a natural expectation that the premises should do some work and should be relevant to the conclusion - things that are true of the arguments that we find useful in real life."

But are these things TRUE of the arguments we find useful in real life? In real life I think we are often deceived and exploited by such natural expectations. It is certainly useful to the politician and the advertiser that the audience 'swallows' their conclusions because of such natural expectations, but is it useful to the recipient of their rhetoric?

Actually I somewhat disagree about pushing 'the consequences of practical need very far'. I agree that modal logic is not obviously useful in everyday life, but I think the need for basic logical reasoning has never been greater. (Mind you the public need for scientific 'literacy' and for a public understanding of statistics is also great.)