# Thread: Why no science of logic?

1. Originally Posted by Speakpigeon
Originally Posted by steve_bank
Math and science are consider different disciplines. Science deals with physical processes. Science looks at the biological process of the brain that could give rise to logic.

Since the rise of computers logic has moved from philosophy to computer science, which is considered a separate discipline from math, although there is overlap.

It is heavy reading, you could try to read Knuth's books especially Semi Numerical Algorithms. The focus and attention is there, but it is has evolved far beyond Aristotle and his syllogisms. Classical logic from philosophy has little direct use.

There are several applied forms of symbolic logic, one being Boolean Algebra with a standard set of electrical symbols which I am familiar with.

BNF is used to describe the logic behind each instruction in a processor instruction ire set.

https://en.wikipedia.org/wiki/Backus%E2%80%93Naur_form

Depending on what you work on symbolic and formal logic are common.
There is symbol;ic language to describe computer languages, part of that covered under Theory Of Computaion.
Thanks for your response but no. Read my post again: "By science of logic, I mean a scientific investigation of logic as objective performance and manifest capability of human beings".

Computer scientists defer to mathematical logic for the fundamentals. I don't and my whole point is that a science of logic shouldn't either. And quite obviously so, in my view.
EB
And reread my response. Research in logic has been going on for the last 200 years in different areas. One of the more recent is commercial neural nets. The thing is you have to actually read books and papers to get current. The answers to your questions exists, but there is no neat simple answer. You have to work to build understanding.

Formal logic.. if then, or, and, exclusive or, negation and the rest. If you look at he instruction set for any processor you will find what you call Aristotelian logic functions.

Are you familiar with Fuzzy Logic, which like neural nets has commercial application? There are processors based on fuzzy logic. Fuzzy Logic is not an intectual debate or philiosphical dicusion, it is in use.

https://en.wikipedia.org/wiki/Fuzzy_logic

Fuzzy logic is a form of many-valued logic in which the truth values of variables may be any real number between 0 and 1 inclusive. It is employed to handle the concept of partial truth, where the truth value may range between completely true and completely false.[1] By contrast, in Boolean logic, the truth values of variables may only be the integer values 0 or 1.

The term fuzzy logic was introduced with the 1965 proposal of fuzzy set theory by Lotfi Zadeh.[2][3] Fuzzy logic had however been studied since the 1920s, as infinite-valued logic—notably by Łukasiewicz and Tarski.[4]

It is based on the observation that people make decisions based on imprecise and non-numerical information, fuzzy models or sets are mathematical means of representing vagueness and imprecise information, hence the term fuzzy. These models have the capability of recognising, representing, manipulating, interpreting, and utilising data and information that are vague and lack certainty.[5]

Fuzzy logic has been applied to many fields, from control theory to artificial intelligence.

Overview

Classical logic only permits conclusions which are either true or false. However, there are also propositions with variable answers, such as one might find when asking a group of people to identify a color. In such instances, the truth appears as the result of reasoning from inexact or partial knowledge in which the sampled answers are mapped on a spectrum.[citation needed]

Both degrees of truth and probabilities range between 0 and 1 and hence may seem similar at first, but fuzzy logic uses degrees of truth as a mathematical model of vagueness, while probability is a mathematical model of ignorance.[6]

Applying truth values

A basic application might characterize various sub-ranges of a continuous variable. For instance, a temperature measurement for anti-lock brakes might have several separate membership functions defining particular temperature ranges needed to control the brakes properly. Each function maps the same temperature value to a truth value in the 0 to 1 range. These truth values can then be used to determine how the brakes should be controlled.[7]

Linguistic variables

While variables in mathematics usually take numerical values, in fuzzy logic applications, non-numeric values are often used to facilitate the expression of rules and facts.[8]

A linguistic variable such as age may accept values such as young and its antonym old. Because natural languages do not always contain enough value terms to express a fuzzy value scale, it is common practice to modify linguistic values with adjectives or adverbs. For example, we can use the hedges rather and somewhat to construct the additional values rather old or somewhat young.

Fuzzification operations can map mathematical input values into fuzzy membership functions. And the opposite de-fuzzifying operations can be used to map a fuzzy output membership function into a "crisp" output value that can be then used for decision or control purposes.

2. Yeah, that's all irrelevant to my question. I'm talking about deductive logic. Other kinds of logic are legitimate objects of research but I'm not interested, at least for now, essentially given that there is only 24 hours in a day.

Reading is fine, but most books start off saying something to the effect that standard mathematical logic is assumed all good. Well, wrong assumption and it shows neatly how most experts can be experts and actually 100% wrong. That's a direct consequence of human nature, nothing personal. It's just a fact, but you need to take this into account when you try to understand something.

Computers and electronic logic is not logic. We use deductive logic to reason about computers because it works, essentially because computers have been designed precisely to this effect, but computer logic is no more logic than the physical world is logic. Instead, our understanding of computers and the world is made possible by our logical capabilities applied to our models of computers and the world. The result is that you won't validate any formal model of logic by looking at computers. To make a scientific model of logic, you need to look at how people reason. There's no other avenue. And if you don't do that, what's left to you is just to accept without evidence (and without discussion) the model mathematicians say is good, although they themselves have no evidence that it is and although they don't actually show that they understand anything about logic.
EB

3. Originally Posted by Speakpigeon
Yeah, that's all irrelevant to my question. I'm talking about deductive logic. Other kinds of logic are legitimate objects of research but I'm not interested, at least for now, essentially given that there is only 24 hours in a day.

Reading is fine, but most books start off saying something to the effect that standard mathematical logic is assumed all good. Well, wrong assumption and it shows neatly how most experts can be experts and actually 100% wrong. That's a direct consequence of human nature, nothing personal. It's just a fact, but you need to take this into account when you try to understand something.

Computers and electronic logic is not logic. We use deductive logic to reason about computers because it works, essentially because computers have been designed precisely to this effect, but computer logic is no more logic than the physical world is logic. Instead, our understanding of computers and the world is made possible by our logical capabilities applied to our models of computers and the world. The result is that you won't validate any formal model of logic by looking at computers. To make a scientific model of logic, you need to look at how people reason. There's no other avenue. And if you don't do that, what's left to you is just to accept without evidence (and without discussion) the model mathematicians say is good, although they themselves have no evidence that it is and although they don't actually show that they understand anything about logic.
EB
Then this should be on philosophy. Read the fuzzy link, it was derived to emulate how people reason. It is how Ithink and reason on problems, a kind of weighting of variables. Nobody uses Aristotelian logic and syllogisms.

Deductive and inductive are relative string points, one does not exist without the other.

A car crashes and a forensic team arrives. They can start with skid marks and road conditions and walk towards the car, or start at the car and work back to the skid marks. Backwards/forwards, top down/bottom up. deductive/inductive.

General to the specific starting at the skids ending in the specific car crash position. Specific to the general, starting at the specific car crash position and working back to general conditions leading to the crash. On practice deductive and inductive can lead to different conclusions, hence real reasoning combines both deductive and inductive. On this I speak from experience having done forensic troubleshooting on systems. I had logic in philosophy in college.

Was Sherlock Holms deductive or inductive?

As Shakespeare wrote the trouble is not in the stars it is in us, or the old maxim philosopher know thyself. Try figuring out yourself first. Or another, the door opens inwards...and so on and so forth.

I expect there is plenty of work under Cognitive Psychology, had a class. The thing is philosophy does not include much anymore. It is all under math science, psychology, linguistics and the rest. You are looking in the wrong places.

4. Originally Posted by steve_bank
Originally Posted by Speakpigeon
Yeah, that's all irrelevant to my question. I'm talking about deductive logic. Other kinds of logic are legitimate objects of research but I'm not interested, at least for now, essentially given that there is only 24 hours in a day.

Reading is fine, but most books start off saying something to the effect that standard mathematical logic is assumed all good. Well, wrong assumption and it shows neatly how most experts can be experts and actually 100% wrong. That's a direct consequence of human nature, nothing personal. It's just a fact, but you need to take this into account when you try to understand something.

Computers and electronic logic is not logic. We use deductive logic to reason about computers because it works, essentially because computers have been designed precisely to this effect, but computer logic is no more logic than the physical world is logic. Instead, our understanding of computers and the world is made possible by our logical capabilities applied to our models of computers and the world. The result is that you won't validate any formal model of logic by looking at computers. To make a scientific model of logic, you need to look at how people reason. There's no other avenue. And if you don't do that, what's left to you is just to accept without evidence (and without discussion) the model mathematicians say is good, although they themselves have no evidence that it is and although they don't actually show that they understand anything about logic.
EB
Then this should be on philosophy.
This thread is about the science of logic and you think it should be in philosophy?! You're beyond reprieve, Steve.

Originally Posted by steve_bank
Read the fuzzy link, it was derived to emulate how people reason.
Sure, I understand that, and look very carefully, there's no model of deductive logic there. See?

Originally Posted by steve_bank
It is how Ithink and reason on problems, a kind of weighting of variables. Nobody uses Aristotelian logic and syllogisms.
You don't know what is a syllogism, apparently. And you clearly don't know what is Aristotelian logic either.

Originally Posted by steve_bank
Deductive and inductive are relative string points, one does not exist without the other.
Not entirely false, just half false. Fifty-fifty, sort of like the answer of someone who doesn't understand what are the deduction and the induction.

Originally Posted by steve_bank
Was Sherlock Holms deductive or inductive?
Sure, we all use both. So? How does that explain deduction?

You're a big mouth when it comes to criticising philosophy and metaphysics. Yet, here you are, going on and on and on, just exhibiting your little personal philosophy of logic and nothing else. Ain't that ironical?
EB

5. Originally Posted by Koyaanisqatsi
Nothing is "objective," merely presumed or accepted to be objective.
If nothing is objectively true, then the claim that nothing is objectively true isn't objectively true. It's just your opinion, which anyone is free to dismiss or deny.

6. I go by Popper. The only thing we can reasonably take as objective is an experiment. From Popper I would be an Instrumentalist. Truly objective is data from an experiment. As discussion grows around the experiment it becomes increasingly subjective ending in philosophy.

7. Originally Posted by Speakpigeon
Why no science of logic?

By science of logic, I mean a scientific investigation of logic as objective performance and manifest capability of human beings, investigation that would try to develop a formal model of logic which would be accurate and operational.

I can't think of any important aspect of the empirical world which is similarly neglected by science.

There doesn't seem to be any practical impossibility.

Cost would not be a significant factor.

Logic seems to be a rather crucial aspect of human intelligence, which is itself at the centre of the very costly drive to produce artificial intelligence systems. The usefulness of an accurate formal model of logic seems therefore beyond question.

So, 2,400 years after Aristotle, why is there still, in the 21st century, no science of logic?
EB
Interestingly, I was just having a conversation regarding the "science" of AI. quotes because it is not a science. It is considered a discipline of Applied Mathematics (calculus). I guess Logic can be considered the same... a function of the tool (math).

8. Originally Posted by Speakpigeon

This thread is about the science of logic and you think it should be in philosophy?! You're beyond reprieve, Steve.

Originally Posted by steve_bank
Read the fuzzy link, it was derived to emulate how people reason.
Sure, I understand that, and look very carefully, there's no model of deductive logic there. See?

Originally Posted by steve_bank
It is how Ithink and reason on problems, a kind of weighting of variables. Nobody uses Aristotelian logic and syllogisms.
You don't know what is a syllogism, apparently. And you clearly don't know what is Aristotelian logic either.

Originally Posted by steve_bank
Deductive and inductive are relative string points, one does not exist without the other.
Not entirely false, just half false. Fifty-fifty, sort of like the answer of someone who doesn't understand what are the deduction and the induction.

Originally Posted by steve_bank
Was Sherlock Holms deductive or inductive?
Sure, we all use both. So? How does that explain deduction?

You're a big mouth when it comes to criticising philosophy and metaphysics. Yet, here you are, going on and on and on, just exhibiting your little personal philosophy of logic and nothing else. Ain't that ironical?
EB
There is no science of logic. Unless you say Computer Sconce, developing logic implemented on machines. Logical proofs are mathematics. In math there is applied math and theoretical math. As I said there is a wealth of research on logic and reasoning. It is not in philosophy. AI is the current hot research.

Views on logic are subjective and philosophical. Most engineers and scientists are applied mathematicians and logicians.

Have you ever stood up in front of a group of peers and make logical argument in the real world and defend it? You are getting worked up over something imagined, logic and reasoning is well understood and practiced. People just don't goi around formalizing it or discussing it, we apply it.

How does that explain desuction? 'I hear and I forget. I see and I remember. I do and I understand'. There is no explanation, there is understanding derived from experience. You appear to be looking for a simple equation or stemnt that will give you understanding. Does not exist.

A crime has been committed a murder. Holms arrives at the scene and works back from evidence to a motive and murderer. Deductive or inductive. We learn mostly by example.

A room is in a mess and Holmes arrives. based on observedevidence he concludes a murder has occurred but there is no body or blood. Deceptive or inductive?

First understand what deductive and inductive means before you invoke deductive logic. Try Holmes and also Hercule Poirot.

9. Originally Posted by Gun Nut
Interestingly, I was just having a conversation regarding the "science" of AI. quotes because it is not a science. It is considered a discipline of Applied Mathematics (calculus). I guess Logic can be considered the same... a function of the tool (math).
No. The performance of humans in deductive logic is an empirical fact. The logical capacity of the human brain is an empirical fact.

What you say here doesn't even make sense. People routinely do deductive logic without even realising it and they certainly don't need any formal method, let alone mathematics. Aristotle 2,500 years ago, the Stoics 2,400 years ago, the Scholastics 500 years ago, all worked on formal logic with zero input from mathematics. Mathematicians only got interested in logic in the 19th century and Boole at the time talked of the "laws of thought". Your view is really a sad reflection on the fact that mathematical logic has mislead people into believing logic is just what mathematicians do. It's not. Logic is a performance of humans and a capacity of the brain. Mathematical logic just brainwashed everybody. This properly amazing.
EB

10. Originally Posted by steve_bank
There is no science of logic.
Yeah, I know. Why?
EB

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