a priori, a posteriori

OhMan

Member
English, AUS
How would you use these in a sentence correctly? This is what I have so far:

You are making an a priori assumption that because God exists the existence of our souls must logically follow.

Do not take the existence of God for granted, but demonstrate it a posteriori, because I have not been able to do so.
 
  • owlman5

    Senior Member
    English-US
    Hello, Oh Man. I'd say you're using these terms correctly. As long as you use them to distinguish between inductive and deductive reasoning, you should be using them well.
     

    Thomas Tompion

    Senior Member
    English - England
    In philosophy a priori means without recourse to empirical data; an a priori truth is something which can be shown to be true without our knowing anything outside the statement. Many a priori statements seem to be self-evident, like All cows are born from cows, and seem hardly worth saying. Statements which are true a postiori, on the other hand, require empirical knowledge for verification, like Some cows are lame.

    You are making an a priori assumption that because God exists the existence of our souls must logically follow.

    I'm not clear that this sentence uses the expression correctly, but I'm pretty sure the speaker is saying that the other person defines God as an entity which made man with souls, and so if God exists, men have souls.
     
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    OhMan

    Member
    English, AUS
    What if I modify the sentence as follows:

    You are assuming a priori that because God exists the existence of our souls must logically follow.

    Would this be correct? Also is there some sort of rule for italicizing Latin phrases?
     

    Cagey

    post mod (English Only / Latin)
    English - US
    I italicize phrases in another language than English. This is customary in the articles I read.

    The sentence is grammatical. I can't comment on whether it is correct, because it is not clear to me what you intend a priori to mean. Will you tell us in different simpler words what you mean to tell the person you are addressing?
     

    Thomas Tompion

    Senior Member
    English - England
    What if I modify the sentence as follows:

    You are assuming a priori that because God exists the existence of our souls must logically follow.

    Would this be correct? Also is there some sort of rule for italicizing Latin phrases?
    I don't like it, OhMan, because a priori is a way of classifying statements, into the manner in which they can be verified. What you are assuming a priori is that God is an entity which makes man with souls; what you are saying he assumes is what follows from that.
     

    OhMan

    Member
    English, AUS
    I am saying that my opponent has a belief in God that he thinks is self evident or axiomatically correct. So, if he believes God to exist a priori, then his argument for a soul naturally follows from that premise. I find this to be begging the question, because it is that very premise that we are trying to establish. Therefore, I would ask him to give evidence for a soul a posteriori.

    So the fallacy would be as follows:
    Does God exist?
    Yes, because we have souls.
    Well, why do we have souls?
    Because God imbues us with them.
    Well this is begging the question, you can't give evidence for the existence of souls by invoking God, because God is the very subject in which we are discussing.


    Makes sense? I'm just not to clear how to use them in a sentence.
     

    Thomas Tompion

    Senior Member
    English - England
    When you outline the fallacy, I don't know why you leave the important premise (that making men with souls is part of his definition of God) so late in the argument. Also I'd rather see you present the argument without the rhetorical questions, but that's a matter of taste.

    Your friend is making two assumptions: that only God can imbue men with souls and that men are being created with souls. From this it can be shown a priori (by looking at the definitions of the words) that God exists. No a postiori evidence is necessary.

    That's how I see it.
     

    OhMan

    Member
    English, AUS
    No, I think you have misunderstood. He is trying to prove to me that God exists. When I ask him what evidence can he give for the existence of God, he says the human soul. When I ask him why do you think we have souls, he says God imbued us with them at some point during our evolutionary history.

    So in his explanation for the existence of the soul, he invokes God, which you see, is a circular argument. I want him to give evidence for a soul a posteriori, rather than having him using an a priori explanation which just also happens to be a logical fallacy.

    My presenting of the argument with questions inserted was merely for your benefit because you said you did not understand. This is not how I laid out my argument in actuality.
     
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    Thomas Tompion

    Senior Member
    English - England
    Hello OhMan,

    Remember that your question was about the correct use of the expressions a priori and a postiori. I have concentrated on that issue. I'm sorry if my previous answer wasn't clear. I have been more concerned with correct use of the expressions than with the validity of any argument. I think I know exactly what your friend is saying and how you are trying to refute him. This is, after all, a very famous argument.

    I'm still not happy that you are using the expressions correctly, and I'll try to show you why:

    [...] I want him to give evidence for a soul a posteriori, rather than having than using an a priori explanation which just also happens to be a logical fallacy.
    You can ask him for a posteriori evidence that we have souls, certainly. I wouldn't expect him to be able to do so. I've never heard anyone start to do so. Where does one start looking?

    What he has given is an a priori justification - you say explanation: I'm not happy that the a priori can explain.

    Also and this may be by the way, I'm not sure I can see anything logically contradictory in his position: like most a priori arguments it doesn't tell us much - I know he's unmarried because he's a bachelor.
     
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    OhMan

    Member
    English, AUS
    So, you think I should ask him to give me some more evidence apart from the soul, since the soul doesn't explain anything?

    I thought a priori/a posteriori was synonymous with deductive/inductive, or assumed/proven.

    Also, why do you keep spelling a posteriori like a postiori, is that a typo or some sort of language difference?
     

    Thomas Tompion

    Senior Member
    English - England
    So, you think I should ask him to give me some more evidence apart from the soul, since the soul doesn't explain anything? I don't have a view on what you should do. I'm only concerned with your use of the expressions.

    I thought a priori/a posteriori was synonymous with deductive/inductive, or assumed/proven. I suspect a lot of people think this. It's not quite true, as I've been trying to explain. I think you should regard a priori and a posteriori as ways of describing possible means of justifying a statement, rather than as logical processes.

    Also, why do you keep spelling a posteriori like a postiori, is that a typo or some sort of language difference? No, just an error. Thanks for pointing it out. I've never been able to spell.
     

    OhMan

    Member
    English, AUS
    Well forgive me but would you be able to give me some sort of source for your information regarding a priori/a posteriori meaning? I think it would be beneficial for me to read this source rather than just take you on your word.
     

    Thomas Tompion

    Senior Member
    English - England
    Well forgive me but would you be able to give me some sort of source for your information regarding a priori/a posteriori meaning? I think it would be beneficial for me to read this source rather than just take you on your word.
    Look it up anywhere on the web. My only claim to authority is a good honours degree in Philosophy at one of our most famous universities. That doesn't mean I can't make mistakes, just like the people who write articles in Wikipedia on the subject.
     
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