General form: X makes Y seem impossible, yet nevertheless Y is possible.
Can’t we just reject X because we take Y to be possible, which contradicts
taking X seriously?
Y=“how is freedom possible?”
X = “we are chemical/physical beings”
“how is knowledge of the external world possible?”
X = skepticism “How do you know you’re not dreaming / in the Matrix?”
you don’t independently know that you’re not in the Matrix /
brain in the vat, so how could you
know that your hand is in front of you?
The skeptic has put an insuperable requirement for knowledge of the
Two possible replies:
Say the requirement is not genuine
More promising since requirements are usually designed to be
unfulfillable (though they still are very compelling)
Challenge the word “independently”
challenging skeptic’s assumed notions of epistemic priority
because you are accused of question begging if you say “I know I
have a hand, so therefore I’m not a handless brain in a vat”
GE Moore strategy: argue from knowledge to knowledge rather from
ignorance to ignorance.
Say we can satisfy the requirement
Sherlock Holmes meets you for the first time and says “ah I see you’re from
NJ”. “how did sherlock holmes know this?”
X = “given that I didn’t do anything to reveal my origin”
Immanuel Kant ‘grandfather of how possible questions’ and inventor of trancendental arguments
How is mathematical knowledge possible? How is pure science possible?
For the former, Kant answers by drawing attention to how diagramatic
reasoning is crucial.
One can respond to how diagrams (with, say, specific triangles) could
prove general properties (e.g. about triangles in general) and Kant has a
He’s not asking from an epistemological perspective.
These are interesting b/c they are examples of synthetic a priori
How is that kind of knowledge possible? (given that it must be possible in
virtue of mathematical knowledge existing)
X = “where does the knowledge come from if not experience nor analysis of
start off with assumption we have a certain experience, then try to find
necessary conditions for us to have that experience
E.g. external world skeptics believe we have inner experience. Kant argues
that outer experience is a necessary precondition for inner experience.
Therefore we have knowledge of the external world.
This doesn’t answer the ‘how possible’ question. It shows that Y is true
but does not dissolve the obstacle X. So again we have something that
seems necessarily true that asserts something that’s possible is
impossible. The skeptic has the upper hand since their arguments aren’t
as abstract / untrustworthy.
But it’s not like Kant thinks his trancendental arguments were designed
to answer his ‘how possible’ questions (some commentators make the
mistake of assuming this).