Sumi
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Post by Sumi on Aug 10, 2004 9:24:41 GMT -5
We just started Harvey's last week and I already need you ladies ;D Can someone tell me in a simple language what exactly is the difference between a sentence and a proposition? It says a proposition is a thought expressed in words. Is this mean that it is a thought which is not written or written? Is this mean that it does not have to be a complete thought? It also says that a sentence is a group of words making complete sense and that each group is also called a proposition. What each group? Thank you all Sumi
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Post by Carolyn on Aug 10, 2004 17:06:26 GMT -5
Some sentences are propositions, and all propositions (so far as I know) are sentences. Harvey is introducing the logical definition of 'proposition' here. It can be confusing, and take you into philosophy if you aren't careful ('What _is_ a thought? Is anything complete apart from God?") Don't go there, or you may never finish Harvey's. "Did you go to the store?" is a sentence. It's not a proposition, though, as it is not a thought. Perhaps 'assertion' would be a clearer word to use, instead of 'thought.' "Please put your pencil on the table," is another sentence which is not a propositoin. It's a command, not a thought. "Sally went to the store," is both a sentence AND a proposition. It asserts something about Sally. You'll run into propositions more later, in logic. For Harvey's it will suffice to know that there are such things as propositions, and that some sentences are propositions. Carolyn
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Sumi
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Post by Sumi on Aug 10, 2004 19:49:29 GMT -5
Thank you for your reply Please read my following examples to see if I understand the difference between the definition of a sentence and a proposition. Example: Sally went to the store. This is obviously a sentence. However, because it is not 'obvious' that it is spoken to someone, (hence it can stand alone as a thought), it also qualifies as a proposition. Example: Please go check the mail for me. Again, obviously a sentence, but here it cannot be a proposition because it cannot stand alone as a thought, since it INVOLVES someone else. Is my understanding in the above examples correct? I would like to learn more about this as my son is entering into the logic stage. Are there any books that you could recommend me to get more prepared for this? Sumi
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Post by Lene Mahler Jaqua on Aug 11, 2004 10:17:54 GMT -5
There are 4 types of sentences:
Declarative, interrogative, imperative, and exclamatory.
A proposition makes a judgment about something. Propositions are sentences which assert a quality or quantity or property (the predicate) about the subject of the sentence.
Roses are red
Roses- subject red- what is being asserted about "roses".
Now, of the 4 types of sentences above, the interrogative and the imperative do not assert anything about the subject.
Imperative: GO TO BED... does not assert anything, it merely states a command.
Interrogative: Did you wash the car? does not assert anything either.
In the case of imperative you are commanding, in the case of interrogative you are inquiring into something.
So my longwinded post is meant to say that sentences which assert something about a subject.... makes some kind of judgment... are propositions. These can be either declarative or sometimes alse exclamatory.
HTH,
Lene
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Sumi
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Post by Sumi on Aug 11, 2004 14:27:53 GMT -5
Thank you Lene I think I understand it now. One more question though. Can an interrogative sentence sometimes be a proposition also? For example: Are you an Indian? or am I still confused I hope it's ok to ask these questions. This is all new to me and I am learning as I go. Sumi
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Post by Lene Mahler Jaqua on Aug 11, 2004 16:35:16 GMT -5
Sumi,
I understand the confusion here. Let me give you an example.
After I explain to you about propositions I ask you the question
"Is this clear?"
Now, that is not a proposition. I am not stating that it is clear, I am unquiring whether it is... so there is no judgment made in my question. Your answer will likely be a proposition... either
It is clear
or
It is not clear.
Interrogative sentences are never propositions because they do not assert (predicate) something about the subject. They only ASK.
Yes, it is more than OK to ask these questions. It's excellent. So many of us read through the section in Harvey with sentences and propositions, don't even blink and ´never notice that there really IS a difference. Congratulations for seeing this and persisting until you understand the difference. It may not seem like an important distinction to your average Joe Q Citizen, but for the purposes of grammar and logic it is very important.
AND if this still doesn't make complete sense you're more than welcome to keep asking and we will keep trying to see if we understand it well enough to explain it to you.
Lene
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Sumi
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Posts: 14
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Post by Sumi on Aug 11, 2004 18:23:47 GMT -5
Lene, You are VERY gracious and understanding I understand what a proposition is now. It is clear ;D In Him, Sumi
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