Why is logic valid?
- Thread starter the
- Start date
The earth is flat. If you were stood anywhere but the very top and it was round you would fall off. This is logical
Two cars hitting each other head on at 50mph each is like hitting a brick wall at 100mph right? 50 + 50 is 100. Wrong. Its like hitting a brick wall at 50mph
There are many truths that seem illogical. There are many obviously true things which aren't true. Most people cant tell the difference. Someone saying something is logical just means it's intuitively true to them. And therefore probably wrong
Two cars hitting each other head on at 50mph each is like hitting a brick wall at 100mph right? 50 + 50 is 100. Wrong. Its like hitting a brick wall at 50mph
There are many truths that seem illogical. There are many obviously true things which aren't true. Most people cant tell the difference. Someone saying something is logical just means it's intuitively true to them. And therefore probably wrong
Logic is only valid if it is impossible for the premises to lead to a false conclusion.
Appeal to authority is a fallacy, but a fallacy doesn't make something false. To think that a fallacy makes something false is a fallacy in itself, called an Argument from fallacy or the "fallacy fallacy."
Appeal to authority is a fallacy, but a fallacy doesn't make something false. To think that a fallacy makes something false is a fallacy in itself, called an Argument from fallacy or the "fallacy fallacy."
What is logical is not always true. It's only true if all the premises are true.
It is possible for a logical statement to not be true in the real world because logic is hypothetical. It is coming to the conclusion that IF A is true and B is true, then C must be true. A and B don't need to be real world true. It is only saying that C would be true if A and B were true.
It is also possible for something to be true and not seem logical because we do not know the correct premises to formulate the conclusion. Or in other words, we know the answer but we don't know the right question.
Actually hitting another car going 50 is not like hitting a brick wall, its like hitting another car....
Haha
In terms of the amount of energy delivered to the car it is like hitting a brick wall. By brick wall people mean something that doesnt break. If it doesnt break then thats 50mph worth of energy going into breaking the car. In a head on collision both cars are, on average, equally destructible as each other. You have 100mph worth of energy which is split between the two giving 50 each. Just like in the brick wall scenario
This is a great example of intuition leading us astray. Physics is like that and therefore reality is like that. Seemingly logical arguments like 50 + 50 = 100 lead us astray all the time
Idiots publish their opinions too
Actual logic is something only a few have studied. Anything most people say about logic is probably invalid. Though that is not to say you need to study it to be logical.
Cars are designed to crumple and break in order to release energy. Brick walls are not...
Having the facts, without sound logic, doesn't guarantee sound conclusions. Conversely, having sound logic, without sound facts, cannot lead to sound conclusions. The best situation is to have both sound facts and logic, which always produces sound conclusions.
Last edited:
You can tell the earth is curved by watching boats on the sea. As they come over the horizon the boat is revealed top first as opposed to all at once like it would if it was flat.
He's kinda missing the point though as logic can only be based on the data you have access to. It would only be logical if you'd seen that. Otherwise the earth appears to be flat.
The umbrella thing? *shrugs*
[MENTION=731]the[/MENTION]
Logic has nothing to do with truth itself. All logic does is ensure that truth values are maintained across arguments. If the premises of a logically valid argument are true, then its conclusion must be true as well. It does not tell you whether or not those premises are in fact true or not. If a valid argument has true premises (and therefore a true conclusion), it is called a sound argument.
I don't think that appeal to authority has anything to do with this situation. Instead, the person you've seen posting arguments just doesn't understand logic at all.
As for the validity of logic itself, it depends on what type of logic you mean. Inductive logic is invalid according to deductive logic.
Logic has nothing to do with truth itself. All logic does is ensure that truth values are maintained across arguments. If the premises of a logically valid argument are true, then its conclusion must be true as well. It does not tell you whether or not those premises are in fact true or not. If a valid argument has true premises (and therefore a true conclusion), it is called a sound argument.
I don't think that appeal to authority has anything to do with this situation. Instead, the person you've seen posting arguments just doesn't understand logic at all.
As for the validity of logic itself, it depends on what type of logic you mean. Inductive logic is invalid according to deductive logic.
Logic isn't an authority. It's a set of steps that can lead you to an inevitable conclusion. That doesn't mean that every time someone says something is logical that it actually is, but if the logic is sound then there is nothing wrong with that. Now you could maybe say that the person claiming that something is logical is a false authority on logic if their logic isn't valid I suppose.
I think when someone argues that something is logical, they assume that a logical argument must have valid reasoning to support it, so that somehow proves that it's a better way of thinking than an argument based on emotions for example. So, yes, in some sense, we view it as highly authoritative to say that an argument is better or even superior if it is logical. However, emotional reasons can also be valid for an argument, although they may not be viewed as sound and may be quickly dismissed.
For example, it is illogical to cry if someone dies because you can't bring them back from the dead by crying. This is a common "logical" argument. Another example: It doesn't make sense to grieve someone's death because people die everyday. Both arguments appear logical, and would seem to easily dismiss any opposing view, but they really can't. They ignore the emotional reality of the subject. People may die everyday, but not the same people. Life is unique. The person whether stranger, family member or coworker will only die once. You grieve the loss of that person's life because you know they won't be able to live again, and you want to honor the memory of the life they lived. So, whether or not crying or grieving will bring them back is irrelevant in the case for grief. So, simply because grief is not a "logical" behavioral choice hardly makes it an invalid one.
So, yes, sometimes logic is irrelevant, because what's valid is more significant.
For example, it is illogical to cry if someone dies because you can't bring them back from the dead by crying. This is a common "logical" argument. Another example: It doesn't make sense to grieve someone's death because people die everyday. Both arguments appear logical, and would seem to easily dismiss any opposing view, but they really can't. They ignore the emotional reality of the subject. People may die everyday, but not the same people. Life is unique. The person whether stranger, family member or coworker will only die once. You grieve the loss of that person's life because you know they won't be able to live again, and you want to honor the memory of the life they lived. So, whether or not crying or grieving will bring them back is irrelevant in the case for grief. So, simply because grief is not a "logical" behavioral choice hardly makes it an invalid one.
So, yes, sometimes logic is irrelevant, because what's valid is more significant.
Rainbows are circular, reflections are circular, the moon appears to be circular with the sun. It is logical the earth is circular. Spinning around the sun on axis like a top, it cannot be to me logical for the earth to be flat. This is based on other knowledge we have to see.
When we have seen rain so many times and have gotten caught in it a few, it is logical to see clouds and wind and think rain. The umbrella is our mind adapting to past circumstances. I see it as being logical.
While I see your first paragraph, I cannot see the second. It is logical to grieve from the loss of a loved one. Love is what makes the world go round(not flat..ha), so grieving is an understandable reaction to loss of someone we love. Tears are logical to me because they represent loss and grief through love. Without love, I am become as sounding brass or a tinkling cymbal. Without love, why cry. I find it like losing a connection to the heart; no connection, no reason for tears and grief if we know them not.
Human nature allows us to grieve people we do not even know. We see a disaster on TV and cry. I dare say most do not cry because they wish to cry: it just happens. My cup overfloweth.
A few misconceptions about logic here:
1) Only propositions and arguments can be valid. It makes no sense to ask if logic is valid because logic is a tool, not an argument or proposition. The process of using logic is called deduction.
2) An appeal to authority posses problems that are quite independant of logic (or deduction).
3) Truth is also independant of logic. Logic tells us which conclusions follow from, or are entailed by, a set premises. Whether something is true is a different matter entirely.
1) Only propositions and arguments can be valid. It makes no sense to ask if logic is valid because logic is a tool, not an argument or proposition. The process of using logic is called deduction.
2) An appeal to authority posses problems that are quite independant of logic (or deduction).
3) Truth is also independant of logic. Logic tells us which conclusions follow from, or are entailed by, a set premises. Whether something is true is a different matter entirely.