No mathematical proposition can be proven true by observation. It follows that it is impossible to know any mathematical proposition to be true.
The conclusion follows logically if which one of the following is assumed?
(A) Only propositions that can be proven true can be known to be true.
(B) Observation alone cannot be used to prove the truth of any proposition.
(C) If a proposition can be proven true by observation then it can be known to be true.
(D) Knowing a proposition to be true is impossible only if it cannot be proven true by observation.
(E) Knowing a proposition to be true requires proving it true by observation.
Please explain your answers.
Btwn A and E on this one.
A- maybe an assumption. If propositions don't have to be proven true to be known to be true then this would weaken the argument so eliminating this as an option supports the conclusion.
E- maybe an assumption. If a proposition doesnt require to be proven true by observation then the argument is weakened. In order to bolster the author's conclusion there must be no other way to prove the mathematical proposition, otherwise this would weaken the conclusion.
I think E is the correct answer.