But, in a sense, logic isn’t about looking at the world. You can look at the world to get the data to apply the logic to, but when you’re actually doing the logic, you’re not looking at the world at all; you are just inside your head.
Suppose I ask you to look at the world and tell me whether it is, in fact, raining. That is, is “It is raining” a true statement? Suppose you tell me that it is. I can then, without looking at the world, just by applying logic to what you told me, infer that “It is not raining” is a false statement. Or that “It is raining or you have a pencil up your nose” is a true statement.
Or maybe you tell me that “It is raining” is false. I can then use logic to conclude that “It is not raining” is a true statement, or that “It is raining and you’re wearing socks” is a false statement.
Or maybe you tell me you can’t declare “It is raining” to be unambiguously true or false. And that’s fine. If you can assign a specific intermediate value to it, somewhere in between TRUE and FALSE, maybe we could use fuzzy logic. Or we could just say that, since it doesn’t have a specific truth value, it’s not the kind of statement we can use logic on.
So I’m wondering if your objection is really that not every statement has a truth value of either TRUE or FALSE if you check it against the real world and expect to hold that truth value universally and unambiguously. If that’s what you’re saying, well, you’re right, but I think every logician readily acknowledges that.
But it is used by many people to apply to the world; and the example chosen was an applying-to-the-world sort of example.
My objection is that it’s often so mis-applied. And I disagree that every logician readily acknowledges that; in particular, that the person who put that example in a college text would acknowledge it. I never challenged him; but in a later class, with a different professor, I did challenge it. The professor said ‘you’re either in the room or out of the room’ and I got up, went to the door, and stood there with my lower body outside the door and my head and shoulders leaning in and asked him ‘Am I in the room or out of the room?’ He didn’t acknowledge that “not every statement has a truth value of either TRUE or FALSE if you check it against the real world”. He told me that I was being trivial.
The specific example was pretty trivial. When it turns, in the real world, into ‘you’re either with us or against us’, it’s very often not trivial at all. There are murders committed, and all sorts of oppression, because of the idea that ‘if I am right about this, then you must be Wrong. And acknowledging that you might be right would amount to admitting that I must be Wrong and that would be horrible so you need to be wiped out!’
Liminality is a pretty important concept in anthropology, and comes from exactly the example you give (limen = threshold): when you’re on the threshold, you’re in an in-between, transitional place.
I was reading @Velocity’s poll on the parent with the child about to make a life-ending, but world changing-moment, and my first response was to say “of course, it will change the world for the better/greatest good/etc”.
I then realized I’m not a parent, and that I don’t think I can honestly evaluate the emotional bond that entails.
I’d hope I’d have the guts to do it myself, if that were an option. (I don’t know if I would; but I hope so.) So I think I’d have to hope I’d have the guts to accept my child doing it.
I’m not sure if it still works, but I’ve got a vintage HP desktop calculator from circa 1971, similar to this one. It’s almost like a mini-computer, as it can run some very simple programs. And like all old HP calculators, it uses Reverse Polish Notation.
I’ve also got an old probably 1980s era Radio Shack brand solar powered calculator laying around. I used to keep it in my car for calculating my fuel economy, but I have my phone for that now.
My household has 2-3 electronic calculators of various levels of “smart” from a classic “solar” mini that’s good for algebra, to a $200 behemoth advanced graphic model my wife used extensively working on her PhD in Physics.
She also has several sheets and several books with printed tables and values, including log tables.
Otherwise, we have an awesome (unused, but workable) slide rule my wife begged off her father, complete with leather holster suited to carrying a range rifle (similar to the following).
I’ve got an old HP-35 which I bought for $300 in 1973 and no longer works, an HP-16C, a Casio fx-270w which I didn’t even remember I had but just found while looking for my 16C, two slide rules, a Piccolo-S mechanical stylus calculator which absolutely entranced me as a child, and a soroban which I also spent a lot of time learning to use as a child. Oh, and the 23rd edition of CRC Standard Mathematical Tables which includes logarithm tables. A friend of mine recently bought a Curta which is totally awesome. I’d love to have one but I can’t justify the cost; I’d probably spend a week playing with it and then put in on a shelf and never touch it again.
