Thread: What does Common Sense mean in Physics? What does Logic mean in Physics?

I heard it very often.

Originally Posted by Strange

Sounds like you are trying to apply a combination of common sense and classical physics to the understanding of black holes.

That never works well.

Originally Posted by Dywyddyr

Logic and religion generally don't mix.
There is no logical tie between those two things

Originally Posted by Strange

That does not logically follow.

Originally Posted by tk421

The second statement does not logically follow from the first.

Originally Posted by forrest noble

People, by illogical reasoning, can identify themselves as being ignorant to those that understand the rules of formal debate and logic.

Ad Hominem defined: Involves all persons who make illogical arguments by:

1. (of an argument or reaction) appealing to the emotions of others without using subject-related reason or logic.
2. attacking an opponent's motives, character, suggesting ineptitudes etc., rather than the policy or position they maintain.
3. insults or statements to belittling someone, without subject-related specifics.

Ad hominem - Wikipedia, the free encyclopedia

Define Logic?
Define Common Sense?
Is Logic = Common Sense?
In Science, meanings of words differ quite a bit from the English Dictionary.

Originally Posted by Strange

Sounds like you are trying to apply a combination of common sense and classical physics to the understanding of black holes.

That never works well.

If i shouldn't apply common sense, i should apply illogicality?
And if i apply illogicality, people would scold me, right? refer the quotes up there.





I hope the question i asked is a decent question

Common sense can sometimes guide you to a correct understanding but often it leads you astray. Many of the cutting edge topics in physics today are beyond the scope of our daily lives and thus beyond the scope of common sense. What is more appropriate to apply in place of common sense is a proper background knowledge in the relevant physics. Experiment reigns above all, however. You cannot escape this and even the brightest physicists come up with theories that are dead wrong, so don't feel bad if you misunderstand something. Just take it as an opportunity to learn more.

Well, my mom said "Common sense = The obvious". cant you use "the obvious" in reasoning in science?

common means average, not special. it can, in the context of common sense, be attributed to what exists among the least among us.

Sense, in this context, means one's ability to conceptualize their surroundings.

So basically, common sense, is used to refer to what is easy to conceptualize for even the dumbest of our species.

So common sense, is not necessarily noteworthy of being intellectually special and can even, considering just how dumb our dumbest species members are, be considered a bit dim. While common sense may just be able to keep you alive, it usually requires a bit more intellectual ability to actually be able to be successful in understanding more complex models and patterns of reality.

I wonder if the British like to say, "your sense is dead common"... sorry that was just a side tangent.

Originally Posted by ryanawe123

Well, my mom said "Common sense = The obvious". cant you use "the obvious" in reasoning in science?

What's obvious to a trained physicist is not so obvious to a layman. You can use any sort of reasoning you want in science, but if it is not backed up by experiment then it doesn't matter.

Originally Posted by ryanawe123

Well, my mom said "Common sense = The obvious". cant you use "the obvious" in reasoning in science?

No, you can't.

'Commons sense' and the 'obvious' are based on our experiences with the physical world around us, which is a low-energy, low-gravity, slow moving world. This is not how most of the universe is. The physical actions and reactions we see in our day to day lives is an extremely limited subset of what goes on.

Originally Posted by ryanawe123

Define Logic?

A branch of mathematics/philosophy which studies the methods of reasoning which are "valid"; i.e. able to lead to correct conclusions.

For example, the following is a valid argument:

All men are mortal. (1)
Socrates is a man. (2)
Therefore, Socrates is mortal. (3)

This argument is also "sound"; i.e. its premises (1 and 2) are true and therefore its conclusion (3) is true.

The following argument is not valid and therefore its conclusion is not necessarily true.

All men are mortal.
Socrates is mortal.
Therefore, Socrates is a man.

The following is valid but its premises are not true so it is not sound:

All cups are green.
Socrates is a cup.
Therefore, Socrates is green.

There are many forms of logical argument which are well undertsood. They can be used by computers, for example to prove facts mathematically.

Many people, naming no names (<cough>forrest<cough>) use the word "logical" to mean, "it makes sense to me (so it must be right)".

Define Common Sense?

Judgements made about things based on our everyday experience.

"Oooh. The Sun must be really big and hot. I bet it is nearly as big as my house. And as hot as a burning log"

Rarely of any value in science. In fact, the whole purpose of the scientific method is to eliminate these sort of personal biases.

Is Logic = Common Sense?

Absolutely not.

I hope the question i asked is a decent question

It is a good questions. If more people who post their "personal theories" understood, they might realise why their random musings are not science.

Originally Posted by ryanawe123

Well, my mom said "Common sense = The obvious". cant you use "the obvious" in reasoning in science?

If you have years of experience in a field and in in-depth understanding of the subject then you can, sometimes, use "obvious" as a starting point. As long as you bear in mind there is a chance you will be wrong. (Another problem with people who make up their personal theories: "it must be correct because I thought of it".)

What is obvious to one person may not be obvious to another. Which is why common sense is of little value in science and engineering. There is a good passage about this in Zen and the Art of Motorcycle Maintenance where they are discussing a light that doesn't work.

Originally Posted by Strange

The following is valid but its premises are not true so it is not sound:

All cups are green.
Socrates is a cup.
Therefore, Socrates is green.

whats premises? i dont see anything wrong socrates is green?
whats socrates is it a name?

Originally Posted by ryanawe123

Originally Posted by Strange

The following is valid but its premises are not true so it is not sound:

All cups are green.
Socrates is a cup.
Therefore, Socrates is green.

whats premises? i dont see anything wrong socrates is green?

whats socrates is it a name?

He didn't say it was wrong. He said it was valid.

wrong = invalid
correct = valid

A premise is a presupposed truth, an axiom.

Socrates was a man. A Greek Athenian philosopher who lived a very very long time ago.

While there was a bit of comedy in stating that Socrates is a cup. Basically, he was demonstrating what can also be demonstrated as a mathmatical expression.

IF A = B
And C = B
Then A = C

Originally Posted by Strange

its premises are not true so it is not sound

a presupposed truth is not true? i dont get it, really

The point is that Socrates is not a cup.

All cups are green.
Ryanawe123 is a cup.
Therefore, ryanawe123 is green.

Are you green? If not, can you tell me where the logic was wrong?

Originally Posted by ryanawe123

Originally Posted by Strange

its premises are not true so it is not sound

a presupposed truth is not true? i dont get it, really

Sorry, I should have explained the terminology. A "premise" is an initial statement (which may be true or not). A logical argument derives a "conclusion" from those premises.

If the argument is valid, then the conclusion will always be true if the premises are true (and not true if one or more of the premises are not true). If the argument is not valid, then you cannot know anything about the truth or otherwise of the conclusion, based on the premises.

Socrates was a man. See also: Bill and Ted's Excellent Adventure.

Originally Posted by beefpatty

The point is that Socrates is not a cup.

All cups are green.
Ryanawe123 is a cup.
Therefore, ryanawe123 is green.

Are you green? If not, can you tell me where the logic was wrong?

im not a cup.......

Originally Posted by ryanawe123

Originally Posted by beefpatty

The point is that Socrates is not a cup.

All cups are green.
Ryanawe123 is a cup.
Therefore, ryanawe123 is green.

Are you green? If not, can you tell me where the logic was wrong?

im not a cup.......

That is correct. Because the logical argument is "valid" we know that when you say you are not a cup then we cannot conclude that you are green.

The important (essential) point is to understand the difference between a valid argument which allows you to draw conclusions and the facts (premises) that are used in that argument.

Define Logic?

Logic is a science. There are several kinds of logic, classical two-valued logic. Multi-valued logic and intuistionistic logic. Each are defined by their own respective steps of logical constructs. From which one can derive all said logical followings.

Define Common Sense?

There is no Common Sense. At best it could be ascribed to survival. Not jumping in front of a train for instance. However it is probably mostly referred to as experimentation. Something is commons sense when a simple and easily done test or experiment that anyone can do anywhere revokes the claim. It is common sense things fall towards the center of the earth. etc.

Is Logic = Common Sense?

No, see above.

In Science, meanings of words differ quite a bit from the English Dictionary.

Sometimes, yes, sometimes no. However many concepts are difficult to grasp in just a single language. Hence we try. But nowadays Wikipedia brings you far.