## Paradox of Knowability

Posted by allzermalmer on April 12, 2013

Theorem 5: If there is some true proposition which nobody knows (or has known or will know) to be true, then there is a true proposition which nobody can know to be true

“There are truths that cannot be known. For suppose that all truths can be known. Then all truths actually are known. Otherwise, we may suppose for some p that p but it is not known that p. Then it can be known that p but it is not known that p. But when it is known that thus and such, it is known that thus and it is known that such. So it could be known that p and known that it is not known that p. But what is known is true. So it could be known that p and not known that p. But that is a contradiction, and no contradiction can be true. So all truths are actually known.” W.D. Hart

(1) Assume that if X is true then possible to know that X is true. (2) Then, if X is true & do not know that X is true, then possible to know that both X is true & do not know X is true. (3) But, not possible to know that both X is true & do not know X is true. (4) Not both X is true & do not know X is true. (5) If X is true then do not not know that X is true. (6) If X is true then know that X is true.

What if the World is non-omniscient? This would mean that nobody knows all truths, and nobody ever will. Therefore, there are unknowable truths. If some truth is unknown, then that it is unknown is itself unknowable; Because the world is non-omniscient, there is some unknowable truth. If there at exists at least one Truth, such that Truth is true and Truth is unknown, then there exists at least one Truth, such that Truth is unknown and Truth is unknowable. If there does not exist at least one Truth, such that Truth is unknown and Truth is unknowable, then there does not exist at least one Truth, such that Truth is true and Truth is unknown.

**It is possible that **it is known by someone at some time that both *X is true* & It is not known by someone at some time that *X is true. ***It is possible that **both It is known by someone at some time that *X is true* & It is not known by someone at some time that *X is true (reduction ad absurdum)*

** Non-Omniscience**:

*X is true*& It is not known by someone at some time that

*X is true.*

* Verdicality (KV): *If it is known by someone at some time that

*X is true*, then

*X is true.*

* Distribution (KC): *If it is known by someone at some time that both

*X is true*&

*Y is true*, then both it is known by someone at some time that

*X is true*& It is known by someone at some time that

*Y is true.*

* Non-Contradiction (LNC)*:

**It is not possible that**both

*X is true*&

*X is not true.*

* Clousure (CP): *If

*X is true*implies

*Y is true*&

**it is possible that**X is true, then

**it is possible that**

*Y is true*.

* Knowability (KP):* If

*X is true*then

**it is possible that**it is known by someone at some time that

*X is true.*

(1) Assume that *X is true *& It is not known by someone at some time that *X is true *

(2) **It is possible that **it is known by someone at some time that both *X is true *& It is not known by someone at some time that *X is true. (By KP & (1).
*

*(3) *It is known by someone at some time that both *X is true *& It is not known by someone at some time that *X is true. *It is known by someone at some time that *X is true *& It is known by someone at some time that it is not known by someone at some time that *X is true. *

*(4) *It is known by someone at some time that* both X is true *&* *it is not known by someone at some time that *X is true. *It is known by someone at some time that* X is true *&* *It is not known by someone at some time that* X is true. (By Simp, VK, and Adjunction (and Transitivity implication))*

*(5) ***It is possible that both*** *It is known by someone at some time that* X is true *&* *It is not known by someone at some time that* X is true. (by CP)*

*(6) ***It is not possible that*** *both* *It is known by someone at some time that* X is true *& It is not known by someone at some time that* X is true. (by LNC)*

*(7) ***It is necessary that** not both *X is true* & *X is not true*.

**(8)* *X is true* & It is known by someone at some time that *X is true. (by Reduction Ad Absurdim) *

Thus, If *X is true*, then it is known by someone at some time that *X is true:: If it is not known by someone at some time that X is true, then X is not true.
*

This entry was posted on April 12, 2013 at 4:20 AM and is filed under Philosophy. Tagged: Clousure, Clousure Principle, Distribution, Epistemology, Fich's Paradox, Fitch, Hart, Knowability, Knowability Principle, Knowledg Verdicality, Knowledge, Knowledge Distribution, Logial Non-Contradiction, Logical Non-Contradiction Principle, Metaphysics, Non-Contradiction, Non-Omniscience, Paradox, Paradox of Knowability, True, Truth, Verdicality, W.D. Hart. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.

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