Deduction and induction

[no-one-particular]

if every Swan that I have ever seen was white then is it reasonable that the next Swan I see will be white?
Yes it is a reasonable possibility but it does not prove that the next Swan will be white

 

[fast]

if every Swan that I have ever seen was white then is it reasonable that the next Swan I see will be white?
Yes it is a reasonable possibility but it does not prove that the next Swan will be white

i agree

 

[steve_bnk]

if every Swan that I have ever seen was white then is it reasonable that the next Swan I see will be white?
Yes it is a reasonable possibility but it does not prove that the next Swan will be white

Obviously true, but how is deduction any more reliable?


I observe all swans are white. If I observe a white bird I deduce itmust be a swan.

Both induction and deduction depend on data ad interpretation of data which is not always subject to objective black and white analysis.

SherlockHolmes the deductive detective.


http://www.thescienceofdeduction.co.uk/

'...I'm Sherlock Holmes, the world's only consulting detective.
I'm not going to go into detail about how I do what I do because chances are you wouldn't understand. If you've got a problem that you want me to solve, then contact me. Interesting cases only please.
This is what I do:

• 1. I observe everything.
• 2. From what I observe, I deduce everything.
• 3. When I've eliminated the impossible, whatever remains, no matter how mad it might seem, must be the truth.

If you need assistance, contact me and we'll discuss its potential...'


If deduction is infallible then there can be no people wrongly convicted of a crime.

The only difference between induction and deduction is the starting point.

Start from the conclusion and work backwards to causes, or start from causes and work towards a occlusion.

You can not have one without the other. Both are part of reasoning.

In engineering we call it do top down versus bottom up analysis.

 

[fast]

The only difference between induction and deduction is the starting point.

Start from the conclusion and work backwards to causes, or start from causes and work towards a occlusion.

The vital difference involves entailment.

"A deductive argument is an argument that is intended by the arguer to be (deductively) valid, that is, to provide a guarantee of the truth of the conclusion provided that the argument’s premises (assumptions) are true.

An inductive argument is an argument that is intended by the arguer merely to establish or increase the probability of its conclusion. In an inductive argument, the premises are intended only to be so strong that, if they were true, then it would be unlikely that the conclusion is false."​

 

[steve_bnk]

You can post sound bites and simple isolated examples from sources, but in general there is no clear dichotomy between deduction and induction. Both are required and work together. They both comprise reasoning.


When Holmes worked a crime he looked at the end result or the crime, andthen inductively projected possible outcomes of potential causes in the past. You can not separate deduction and induction. Deduction and induction are simply relative perspectives from a point in reasoning.


As a practical matter, without induction humans would not have progressed. Observation and deduction correlating cause and effect leads to predictions of the future validated by future deduction andso on.


Thetruth of any logic leading to a conclusion depends on the data or premises. Deduction alone is useless.


Ifyou want to assert that deduction is inherently more reliable than induction, then present a proof.


All'syou have to do is look at history to see that deduction itself doesnot always lead to a true conclusion.

 

[fast]

You can post sound bites and simple isolated examples from sources, but in general there is no clear dichotomy between deduction and induction. Both are required and work together. They both comprise reasoning.


When Holmes worked a crime he looked at the end result or the crime, andthen inductively projected possible outcomes of potential causes in the past. You can not separate deduction and induction. Deduction and induction are simply relative perspectives from a point in reasoning.


As a practical matter, without induction humans would not have progressed. Observation and deduction correlating cause and effect leads to predictions of the future validated by future deduction andso on.


Thetruth of any logic leading to a conclusion depends on the data or premises. Deduction alone is useless.


Ifyou want to assert that deduction is inherently more reliable than induction, then present a proof.


All'syou have to do is look at history to see that deduction itself doesnot always lead to a true conclusion.

A deductive argument and an inductive argument are two different kinds of arguments, and our expectations are also different. I wouldn't place fault with a screwdriver for failing to saw as a skill saw would. It's not a failing of the screwdriver to not saw. It's purpose is different. There are those that hold a dim view of induction based on the mistaken belief that induction fails us, but it's not a failure merely because it doesn't do as another tool does.

In both cases, the conclusion is not guaranteed, at least not without the big "if" caveat. See, this is about form, not truth. A perfectly valid deductive argument doesn't necessarily entail the truth of its conclusion. Never does nor must an inductive argument entail or guarantee a conclusion. That's why inductive arguments cannot be valid, for even if (that big if) all premises are true, not even an ensuing true conclusion was guaranteed, but that's not a failing of induction, as it's purpose was never to do such a thing.

 

[steve_bnk]

You can post sound bites and simple isolated examples from sources, but in general there is no clear dichotomy between deduction and induction. Both are required and work together. They both comprise reasoning.


When Holmes worked a crime he looked at the end result or the crime, andthen inductively projected possible outcomes of potential causes in the past. You can not separate deduction and induction. Deduction and induction are simply relative perspectives from a point in reasoning.


As a practical matter, without induction humans would not have progressed. Observation and deduction correlating cause and effect leads to predictions of the future validated by future deduction andso on.


Thetruth of any logic leading to a conclusion depends on the data or premises. Deduction alone is useless.


Ifyou want to assert that deduction is inherently more reliable than induction, then present a proof.


All'syou have to do is look at history to see that deduction itself doesnot always lead to a true conclusion.

A deductive argument and an inductive argument are two different kinds of arguments, and our expectations are also different. I wouldn't place fault with a screwdriver for failing to saw as a skill saw would. It's not a failing of the screwdriver to not saw. It's purpose is different. There are those that hold a dim view of induction based on the mistaken belief that induction fails us, but it's not a failure merely because it doesn't do as another tool does.

In both cases, the conclusion is not guaranteed, at least not without the big "if" caveat. See, this is about form, not truth. A perfectly valid deductive argument doesn't necessarily entail the truth of its conclusion. Never does nor must an inductive argument entail or guarantee a conclusion. That's why inductive arguments cannot be valid, for even if (that big if) all premises are true, not even an ensuing true conclusion was guaranteed, but that's not a failing of induction, as it's purpose was never to do such a thing.

You continue to speak in generalities. Refute my examples I have given to show induction and deduction are really the same, just different perspectives on a problem.

A crash has occurred, a forensics team projects back in time to possible causes inductively testing possible causes affecting the accident. Do you understand what I am saying? Is their starting point induction or deduction, apply your reasoning.

I don't normally use the term, I have done a great deal of forensic analysis on systems. I am speaking from experience.

The Malaysia flight disappeared, is the instigation inductive or deductive?

Explain as a practical matter how do you get to deductionn without induction and vice versa.

The goal of deduction is to reach a conclusion...

 

[fast]

You can post sound bites and simple isolated examples from sources, but in general there is no clear dichotomy between deduction and induction. Both are required and work together. They both comprise reasoning.


When Holmes worked a crime he looked at the end result or the crime, andthen inductively projected possible outcomes of potential causes in the past. You can not separate deduction and induction. Deduction and induction are simply relative perspectives from a point in reasoning.


As a practical matter, without induction humans would not have progressed. Observation and deduction correlating cause and effect leads to predictions of the future validated by future deduction andso on.


Thetruth of any logic leading to a conclusion depends on the data or premises. Deduction alone is useless.


Ifyou want to assert that deduction is inherently more reliable than induction, then present a proof.


All'syou have to do is look at history to see that deduction itself doesnot always lead to a true conclusion.

A deductive argument and an inductive argument are two different kinds of arguments, and our expectations are also different. I wouldn't place fault with a screwdriver for failing to saw as a skill saw would. It's not a failing of the screwdriver to not saw. It's purpose is different. There are those that hold a dim view of induction based on the mistaken belief that induction fails us, but it's not a failure merely because it doesn't do as another tool does.

In both cases, the conclusion is not guaranteed, at least not without the big "if" caveat. See, this is about form, not truth. A perfectly valid deductive argument doesn't necessarily entail the truth of its conclusion. Never does nor must an inductive argument entail or guarantee a conclusion. That's why inductive arguments cannot be valid, for even if (that big if) all premises are true, not even an ensuing true conclusion was guaranteed, but that's not a failing of induction, as it's purpose was never to do such a thing.

You continue to speak in generalities. Refute my examples I have given to show induction and deduction are really the same, just different perspectives on a problem.

A crash has occurred, a forensics team projects back in time to possible causes inductively testing possible causes affecting the accident. Do you understand what I am saying? Is their starting point induction or deduction, apply your reasoning.

I don't normally use the term, I have done a great deal of forensic analysis on systems. I am speaking from experience.

The Malaysia flight disappeared, is the instigation inductive or deductive?

Explain as a practical matter how do you get to deductionn without induction and vice versa.

The goal of deduction is to reach a conclusion...

When you speak of induction and deduction, are you talking about arguments? And what do you mean by inductively testing?

http://www.iep.utm.edu/ded-ind/

 

[Speakpigeon]

Can you give an example of what you see as a typical inductive argument?
EB

Every time I’ve walked by that dog, he hasn’t tried to bite me. So, the next time I walk by that dog he won’t try to bite me.

In this case, I would say that the conclusion is rather obviously false and the argument rather obviously not valid.

If a passport can be valid (in the particular way that passports have to be valid or invalid), I don't see why an inductive argument couldn't (in the particular way that inductive arguments have to be valid or invalid).
EB

 

[Speakpigeon]

deduction tells you whether something is true or false.
Induction tells you whether it is reasonable or unreasonable

to know that something is true beyond a reasonable doubt requires both

Not really, no. For example, I know I feel tired whenever I feel tired. I need neither deduction nor induction.

What you say only really applies to metaphysical claims, for example claims about the material world or about God, with the caveat that you can't say that you really know. Either you know or you don't but if you know it's not "beyond a reasonable doubt" because if there is any possible doubt at all then you just don't know.

That being said, reason does rely on both inductive and deductive inferences.
EB

 

[Speakpigeon]

deduction tells you whether something is true or false.
Induction tells you whether it is reasonable or unreasonable

to know that something is true beyond a reasonable doubt requires both

Deduction and induction use the same logical reasoning.

Can you explain what you mean here?
EB

 

[fast]

Every time I’ve walked by that dog, he hasn’t tried to bite me. So, the next time I walk by that dog he won’t try to bite me.

In this case, I would say that the conclusion is rather obviously false and the argument rather obviously not valid.

If a passport can be valid (in the particular way that passports have to be valid or invalid), I don't see why an inductive argument couldn't (in the particular way that inductive arguments have to be valid or invalid).
EB

What do you mean it's false? It might be, but you don't know that.

Eta: passport validity is an entirely different kind of validity

 

[Speakpigeon]

In this case, I would say that the conclusion is rather obviously false and the argument rather obviously not valid.

If a passport can be valid (in the particular way that passports have to be valid or invalid), I don't see why an inductive argument couldn't (in the particular way that inductive arguments have to be valid or invalid).
EB

What do you mean it's false?

You're right. I meant that it was wrong to draw the conclusion suggested.

It might be, but you don't know that.

That's right, but the inference is wrong. You would have to say instead something like "the next time I walk by that dog he shouldn’t try to bite me".

To say "the dog won’t try to bite me" suggests you know he won't when you cannot know that on the basis of the premise alone.

Even if the dog wouldn't bite you in the event you still wouldn't have known he wouldn't (unless like God you know something nobody else does?).

Eta: passport validity is an entirely different kind of validity

Yes, that's what I said. And inductive validity would have to be a different kind of validity from deductive validity. There's no ambiguity when one says that a passport is valid. So, why should there be one in the case of an induction?

There is no doubt something in common between all three kinds of validity but they are still different things.
EB

 

[fast]

Yes, that's what I said. And inductive validity would have to be a different kind of validity from deductive validity. There's no ambiguity when one says that a passport is valid. So, why should there be one in the case of an induction?

There is no doubt something in common between all three kinds of validity but they are still different things.
EB

That's interesting, but I've never heard of inductive validity posited like that. What would it mean?

 

[Philos]

Folks,

I think an inductive argument would be valid if it showed that we could not be sure of the conclusion.

Alex.

 

[fast]

Folks,

I think an inductive argument would be valid if it showed that we could not be sure of the conclusion.

Alex.

And I think a drink is hot if it's cool to the touch.

 

[Speakpigeon]

Folks,

I think an inductive argument would be valid if it showed that we could not be sure of the conclusion.

Alex.

Me I would certainly say that the following inference it's a valid one:

Most men are no taller than 1.83m;
Jackson is a man;
We don't know anything that would entail that Jackson is taller than 1.83m
Therefore, Jackson is probably no taller than 1.83m.

Doesn't that show that we are not sure of the conclusion?

But, this one wouldn't be valid:

Most men are no taller than 1.83m;
Jackson is a man;
We don't know anything that would entail that Jackson is taller than 1.83m
Therefore, Jackson is no taller than 1.83m.

EB

 

[Speakpigeon]

Yes, that's what I said. And inductive validity would have to be a different kind of validity from deductive validity. There's no ambiguity when one says that a passport is valid. So, why should there be one in the case of an induction?

There is no doubt something in common between all three kinds of validity but they are still different things.
EB

That's interesting, but I've never heard of inductive validity posited like that. What would it mean?

That all rational beings should get to agree with it (if they should).
EB

 

[Speakpigeon]

Yes, that's what I said. And inductive validity would have to be a different kind of validity from deductive validity. There's no ambiguity when one says that a passport is valid. So, why should there be one in the case of an induction?

There is no doubt something in common between all three kinds of validity but they are still different things.
EB

That's interesting, but I've never heard of inductive validity posited like that. What would it mean?

Education Portal: Inductive Validity

Inductive validity means that when one reasons inductively, such reasoning will contain three elements: 1) a premise (the first guiding point), 2) supporting evidence (what makes you believe the premise is true), and 3) a conclusion that is true and viable (valid) AS FAR AS YOU KNOW. The validity of the reasoning is based upon the strength of your supporting evidence, which makes your premise more likely to be true and, hence, your conclusion to be more than likely true.

Inductive reasoning is often used in science and philosophy, since it provides evidence for a belief, even though that belief may someday be found to be false (just ask any scientist!). In other words, inductive reasoning is a 'best guess' that is based on the best available evidence. A basic example might look like this:
All printed books have a binding. I believe this because every book I have read has had a binding. Therefore, any new book that is made will probably have a binding.

It says, "a conclusion that is true and viable (valid) AS FAR AS YOU KNOW"... And the conclusion says "probably".

Much like what I said, I guess.

And there are many other SE hits.

I guess the point is that deductive logic cannot define or specify the terminology applicable to inductive logic.
EB

 

[Speakpigeon]

Sorry-sorry, you may disregard my previous link! It's not very good…


This one is better: Stanford Encyclopedia of Philosophy: Logical Consequence

1. Deductive and Inductive Consequence
In inductively valid arguments, the (joint) truth of the premises is very likely (but not necessarily) sufficient for the truth of the conclusion. An inductively valid argument is such that, as it is often put, its premises make its conclusion more likely or more reasonable (even though the conclusion may well be untrue given the joint truth of the premises).

We seem to disagree on what exactly are inductively valid argument but I'm probably right...

And it does say "inductively valid arguments"…
EB