These are the answers by philosopher
John Kuiper to the
ten questions about intuitionism:
De vragen waren naar mijn mening moeilijk gesteld: natuurlijk kun je best een
discontinue functie definiéren op het continuüm van de reële getallen:
neem het TND maar aan. Het is alsof je aan Lobatchewski vraagt of hij
nu echt zelf gelooft dat er meer dan één lijn door een punt gaat,
evenwijdig aan een andere lijn.
Maar ik heb toch een poging gewaagd, uitgaande van een "liberaal"
intuïtionisme (wat dat ook wezen mag) en een beetje op het gevoel
afgaand:
-
Do you agree that it is impossible to define a total
function from the reals to the reals which is not
continuous?
Yes.
-
Do you agree that the intermediate value theorem does not
hold the way that it is normally stated?
Yes.
-
Do you agree that there are only three infinite
cardinalities?
Yes.
-
Do you agree that the continuum hypothesis is a
meaningful statement that has a definite truth value,
even if we do not know what it is?
Mu.
-
Do you agree that the axiom which states the existence
of an inaccessible cardinal is a meaningful statement
that has a definite truth value, even if we do not know
what it is?
Mu.
-
Do you agree that for any mathematical question it is
easy to build a machine with two lights, yes and no,
where the light marked yes will be on if it is true
and the light marked no will be on if it is false?
No.
-
Do you agree that for any two statements the first
implies the second or the second implies the first?
No.
-
Do you agree that a constructive proof of a theorem
gives more insight than a classical proof?
Mu.
-
Do you agree that mathematics can be done using different
kinds of reasoning, and that depending on the situation
different kinds of reasoning are appropriate?
Yes.
-
Do you agree that all mathematical truths are true,
but that some mathematical truths are more true than
other mathematical truths?
No.