The Instigator
Con (against)
0 Points
The Contender
Pro (for)
7 Points

A priori knowledge exists.

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Post Voting Period
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Voting Style: Open with Elo Restrictions Point System: Select Winner
Started: 7/30/2014 Category: Philosophy
Updated: 3 years ago Status: Post Voting Period
Viewed: 884 times Debate No: 59751
Debate Rounds (4)
Comments (5)
Votes (1)




knowledge - Beliefs for which valid evidence can be presented, or beliefs whose validity can be proven by valid reasoning.
A priori knowledge - Knowledge that can be obtained without any experience.
exists- Can either be registered by human's senses, or it's presence can be concluded by valid reasoning.

Pro has BoP. Topic is resolution. Pro has to make arguments in Round 1. Con must not make a single premise in Round 4. Forfeit in Round 1, 2 or 3 means loss. Links can only be provided to back up challenged premises.


Synthesization of experience
Natural selection (or whatever floats your boat) has embedded within humans an incredible a priori conceptual framework for making sense of reality. Take a given experience: sitting in a lecture room. Our senses give us the speaker, the podium, the color of the walls, the chalkboard, the dimensions of objects in the room, various smells, sounds, colors and a million other phenomena. Somehow, we synthesize this vast array of phenomena into a meaningful experience, and more remarkably, the process is continuous; as external objects change or as we tilt our head, through the passage of time our mind renders the enormity of sense phenomena intelligible. Sense experience allows colors and such to enter our head but it doesn't go nearly far enough in explaining how we synthesize the various phenomena into a coherent whole.

All bachelors are unmarried men.
This is an example of a priori knowledge because it is purely analytic. It's true by definition; if someone's a bachelor, he is a man and unmarried. You don't need sense experience to determine that this statement is true, meaning it is necessarily a priori.

A = A
We don't need experience to tell us that A is equal to A. If two entities represent the same thing, they're necessarily equal to each other.

Possible worlds
Experience can only give us knowledge about what actually is; what is true of this world. Given this, we cannot garner the notion of necessity--things being true in all possible worlds--from experience. It is only contingently true that Stephen Hawking is a very intelligent man, but it's necessarily true that 2+2=4 (there's no world where 2+2=~4). It's easy to delineate necessity from contingency which would not be the case if all our knowledge was gained solely from experience since experience by itself only gives us knowledge of the world as it is--not as the world as it could be but is not, or is but could not have been, or is not and couldn't have been, or is and must be etc...

Debate Round No. 1


Legend: c1(p1+p2) means conclusion c1 is made from premises p1 and p2

I agree with synthesization of expirience part; And I thank my opponent for making such a great exlanation for people who are not familiar with the topic.

I am challenging following statement of my opponent: "All bachelors are unmarried men is an example of a priori knowledge".
p1: A priori knowledge is knowledge that can be obtained without any expirience p2: If one never saw marriage or heard of marriage, he can not know what it is. p3: If one never saw men or heard of men, he can not know what men are. c1(p1+p2): One can not know what unmarried men are a priori. c1(p1+p3)

I am challenging following statement: "You don't need sense experience to determine that this statement is true, meaning it is necessarily a priori."
I learnt that bachelor = unmarried men is true by reading - trough my eyes - with expirience. I claim that I would not not know this statement is true without expirience. And I am asking my opponent to name a possible way.

I am challenging my opponent's statement that A=A" is a priori knowledge:

Statement "If two entities represent the same thing, they're necessarily equal to each other" is true - by the law of logic A=A. But we can't know A=A is true. If we tried to prove it with statement "If two entities represent the same thing, they're necessarily equal to each other", that would be circular reasoning.

Same goes for other laws of logic. We can not KNOW they are true. We only ASSUME they are true.


Synthesization of experience
Con states that he agrees with this part. Since this was an argument for a priori knowledge, that would mean Con concedes the debate, so I'm somewhat confused.

All bachelors are unmarried men
Con is straw manning a priori knowledge in his effort to define a priori knowledge as knowledge completely independent of experience in every possible sense.

"But how could there be any justification apart from experience? Don't people have to learn from experience what bachelors, crows, and knowledge are in order to be justified in believing...The requirement that a priori knowledge (and justification) be absolutely independent of all experience seems too stringent and suggests that all a priori knowledge (and justification) must rest on innate ideas...To say that a person could be justified in believing any of (1a)–(14a) independent of experience means that they could be justified independent of experience beyond that which is needed to acquire the relevant concepts needed to understand those propositions."
-Stanford Encyclopedia of Philosophy

We gain a certain degree of our knowledge through experience, such as the notions of men and marriage. But beyond that, we don't need experience to tell us that all bachelors are unmarried men. That part is a priori and fits perfectly with what philosophers mean when they talk about knowledge independent of experience.

Con says we cannot know any of the laws of logic to be true. Since all knowledge is in some way grounded in logic, I ask how this is not self-defeating to any argument he makes. All of logic and rational thinking points to A being equal to A thus making it valid reasoning and matching the definition of knowledge.

Possible worlds
Ignored completely.

Argument to argument summary
1. Concession
2. Con bases his counter on a strawman notion of a priori requirements
3. Con Bases his counter on self-defeating radical skepticism
4. Ignored

Remember, I only need to win on one point to win this debate.
Debate Round No. 2


Synthesization of experience
Definition of a priori knowledge, that Pro has agreed upon by accepting the debate "Knowledge that can be obtained without any experience." can not by definition be present in synthesization of experience. Aside from that (a priori part), explanation of syntesization of experience is good; and not relevant to debate.

All bachelors are unmarried men
I don't have an idea what "completely independent of experience in every possible sense" is supposed to mean. If one needs some experience to obtain certain knowledge, then that knowledge is not a priori by definition.

My opponent has not pointed out any way I could find out bachelors = unmarried man other than by hearing or reading it. Many philosophers are wrong about lots of things. If it wasn't the case, they would not be rebutting each other all the time.
In fact, many philosophers are taking position that concept of a priori knowledge is based on fallacy.

Answer to the question: All logic and rational thinking does not point to A = A; rather: All logic and rational thinking are based on assumption that A = A. Nothing within the logic suggests that laws of logic are not assumptions.

Possible worlds
I am asking my opponent to excuse the fact that I overlooked his entire paragraph. He has not pointed out what in it is supposed to be example or proof of a priori knowledge, but I will assume it is "2+2=4".
If in imaginary world some people were using exact same mathematics, but only with cipher 2 being 3, and cipher 3 being 2, than 2+2 would be 6. All other alterations are also possible. 2+2=4 is true only because we have agreed upon it worldwide.

It seems like my opponent considers a priori knowledge to be everything that in not first conclusion from experience, but conclusion from [conclusion from experience].
Example: All roses are red - a posteriori; blood is red - a posteriori; Blood and roses have same color - a priori
Is this the case?


Synthesization of experience
It seemed like Con agreed this was a priori, yet he states that it doesn't fit the definition. It's never been contested that we possess an a priori conceptual framework as a precondition to experience. Since this framework is innate, it's indepdendent of experience, so even Con's definition matches it. I also argue that Con's counter is a strawman given the true definition of a priori.

All bachelors are unmarried men
Con's definition pushes a priori knowledge solely into the domain of innate ideas which is only part of what a priori is about. Stanford E. itself says the definition is too stringent and that a priori "means that they could be justified independent of experience beyond that which is needed to acquire the relevant concepts needed to understand those propositions." No experience is required to form tautologies beyond the rellevent notions.

The Stanford Encyclopedia of Phil. is a far better authority than Con. A priori is not solely about innate ideas completely independent of experience.

Either way, I've already proven innate ideas.

If all logic and rational thinking rests on A=A then Con just further proves 1) his radical skepticism refutes his own case which must be based on logic and rational thinking. 2) Nothing is more certain than the fact A=A. 3) A=A is innate.

Con cannot both use logic and reasoning while simltaneously denying it.

If we can know A=A then I win this debate. What could be more easy?

Possible worlds
I don't see how Con could look over an entire argument.

This is not about mathematics. It's about necessity and contingency. A posteriori knowledge only gives us the world as it actually is, but we can know what must be true in every possible world (2+2=4) ergo, empricism is not our only type of knowledge.

Semantics only changes how we express truths not the truths themselves. Mathematics is true independent of language.

Con is obviously confused about what I mean by a priori. I ask him to review the Stanford entry.

Debate Round No. 3


I am arguing that syntesization of experience has nothing to do with a priori knowledge.
"True definition" is definition stated for this debate in Round 1, that Pro agreed upon by accepting. "True definition" is not definition Pro had in mind.

I never denied logic. I said it is not know knowledge, but belief. We can and must use some belief for further reasoning.

Since Pro made appeal to authority, I will quote Friedrich Nietzsche himself: "Necessity and universal importance can never be found in experience! Therefore, they are independent of experience, before each experience! Knowledge which comes a priori, independent of all experience from reason itself, 'pure knowledge'!
'Basic principles of logic, principle of identity and contradiction, are pure knowledge, because they precede each experience.' - But they are not at all knowledge, but parts of faith which have regulative character."


As per the debate structure, I won't be posting anything this round in order that we each get an equal number of rounds.
Debate Round No. 4
5 comments have been posted on this debate. Showing 1 through 5 records.
Posted by phantom 3 years ago
Appreciate it.
Posted by Envisage 3 years ago
Interesting debate, will vote on it later.
Posted by phantom 3 years ago
Character limit is far too small, but I couldn't resist.
Posted by Cold-Mind 3 years ago
Is this definition fine?
Posted by dannyc 3 years ago
Helps to define knowledge.
1 votes has been placed for this debate.
Vote Placed by whiteflame 3 years ago
Who won the debate:-Vote Checkmark
Reasons for voting decision: I do think Con's definition was too restrictive, though unfortunately Pro only seriously contests it and provides a counter definition in R3. So I function based on the original definition. That still doesn't win Con the debate. Fundamentally, Con's argument against A=A is self-defeating, implying that a basic tenet of logic is founded solely in belief. If that is the case, then it calls all of logic into question, and therefore tells me that I should throw out any logic as belief. If I wanted to vote elsewhere, I could easily vote on the possible worlds argument, which gets a strange response from Con that doesn't seem to hit at the a priori aspect of the argument. Similarly, I could vote on synthesizing experience, as Con never contests that a priori knowledge is necessary in order to process experiences. That makes a priori knowledge a predecessor to a posteriori knowledge, and thus a source of knowledge in and of itself.