Global scepticism can be resisted. Discuss
Philosophical scepticism is a less a theory and more a challenge which questions any claim to knowledge. To be more
precise it asks if we have an adequate justification for anything we believe to be true. Philosophical scepticism is
sometimes described as hyperbolic scepticism as – unlike normal incredulity which simply arises from ‘everyday’
reasons for doubt (e.g., we doubt A’s claim he knows B is abroad, because we saw someone who looks just like B
moments ago) – it is willing to entertain any reason for doubt, no matter how fantastical or strange (e.g., the brain in
a vat hypothesis). While local scepticism applies philosophical scepticism to a limited range of knowledge claims (e.g.,
about God or a mind-independent world), global scepticism applies it to all knowledge claims. In this essay we will
explore responses from reliabilism and empiricism. From this we will conclude that global scepticism can be resisted
but not by reliabilism and only to a very limited extent by empiricism.
In a certain respect the reliabilist response to global scepticism rests upon an unwillingness to ‘play the game’
according to the sceptic’s rules. To elaborate, there appears to be an assumption at the heart of scepticism that
knowledge claims require a justification, or to be more precise an adequate justification, and if this isn’t forthcoming
then the claim is open to doubt. However, this assumption is entirely rejected by reliabilism. Instead, according to
reliabilism knowledge is true belief formed by a reliable cognitive process (a process that yields a high percentage of
true belief e.g., perception, testimony, memory, etc.); justification – let alone an adequate justification - isn’t
necessary. This is significant, as it seems to give the reliabilist a free pass to ignore sceptical arguments against
justifications for knowledge (e.g., the evil demon and brain in a vat hypothesis). For example, if realism is true and
perception is a reliable cognitive process, then according to reliabilism we know physical objects exist and global
scepticism has been resisted. Similarly, if our minds are not being manipulated and reason is a reliable cognitive
process, then according to reliabilism we can know analytic truths, and once again global scepticism has been
resisted.
At this point we may object that the conditional (the ‘if’) in the previous two statements is suspect and gives the
sceptic room to challenge the reliabilist position. Hence, surely, we must know our minds are not being manipulated
or that realism is true before we can know analytic truths or that physical objects exist. Without this knowledge we
don’t know that perception and reason are reliable cognitive processes. However, this misses the point, as it assumes
that which the reliabilist rejects, justification. For the reliabilist we don’t need to know that reason or perception are
reliable cognitive processes to possess knowledge. If they are, then we do; this isn’t a matter of justification, but
what is the the case. Thus, all sceptical arguments challenging perception or reason as adequate justifications for
knowledge are irrelevant, and the reliabilist can resist global scepticism.
However, despite its initial promise, we have good reason to reject the reliabilist response as its definition of
knowledge falls foul of Gettier examples. For example, in Gettier’s second example we can assume that Smith used
reliable cognitive processes (e.g., perception and reason) to form his true belief ‘Jones has a Ford or Brown is in
Barcelona’, and Harry used a reliable cognitive process (perception) to form his true belief ‘There is a barn’, but in
both cases – due to the role of luck and coincidence – we are reluctant to say the agent knew the proposition. Thus,
yes, reliabilism resists global scepticism if we accept its definition of knowledge, but inconveniently Gettier examples
reveal we should do no such thing, and therefore reliabilism fails to resist global scepticism.
Turning to empiricism there are two ‘judgments of reason’ we can know: relations of ideas (analytic truths) and
matters of fact (synthetic truths). The former is known a priori by analysing the meaning of words, and the latter is
known a posteriori from perceptions (both from reflection and the senses). If we start with the former, it would
appear that empiricism is on to a winner. Surely, we cannot doubt that all triangles have three sides or that a
bachelor is an unmarried man. They are true by definition and cannot be denied without falling into logical
contradiction. Our knowledge of them is certain.
However, if we take Descartes’ evil demon hypothesis seriously a doubt may enter which cannot be banished. For if
as Descartes suggests an evil demon exists and he has complete control of my mind, not just in terms of what I
perceive but also what I think, then how can I be certain that the demon is not making me think that a triangle has
three side when in fact it does not. With such control, what seems obvious, certain, true by definition, may actually
be far from it. This is difficult prospect to consider, but without any guarantee that our minds are not being
Philosophical scepticism is a less a theory and more a challenge which questions any claim to knowledge. To be more
precise it asks if we have an adequate justification for anything we believe to be true. Philosophical scepticism is
sometimes described as hyperbolic scepticism as – unlike normal incredulity which simply arises from ‘everyday’
reasons for doubt (e.g., we doubt A’s claim he knows B is abroad, because we saw someone who looks just like B
moments ago) – it is willing to entertain any reason for doubt, no matter how fantastical or strange (e.g., the brain in
a vat hypothesis). While local scepticism applies philosophical scepticism to a limited range of knowledge claims (e.g.,
about God or a mind-independent world), global scepticism applies it to all knowledge claims. In this essay we will
explore responses from reliabilism and empiricism. From this we will conclude that global scepticism can be resisted
but not by reliabilism and only to a very limited extent by empiricism.
In a certain respect the reliabilist response to global scepticism rests upon an unwillingness to ‘play the game’
according to the sceptic’s rules. To elaborate, there appears to be an assumption at the heart of scepticism that
knowledge claims require a justification, or to be more precise an adequate justification, and if this isn’t forthcoming
then the claim is open to doubt. However, this assumption is entirely rejected by reliabilism. Instead, according to
reliabilism knowledge is true belief formed by a reliable cognitive process (a process that yields a high percentage of
true belief e.g., perception, testimony, memory, etc.); justification – let alone an adequate justification - isn’t
necessary. This is significant, as it seems to give the reliabilist a free pass to ignore sceptical arguments against
justifications for knowledge (e.g., the evil demon and brain in a vat hypothesis). For example, if realism is true and
perception is a reliable cognitive process, then according to reliabilism we know physical objects exist and global
scepticism has been resisted. Similarly, if our minds are not being manipulated and reason is a reliable cognitive
process, then according to reliabilism we can know analytic truths, and once again global scepticism has been
resisted.
At this point we may object that the conditional (the ‘if’) in the previous two statements is suspect and gives the
sceptic room to challenge the reliabilist position. Hence, surely, we must know our minds are not being manipulated
or that realism is true before we can know analytic truths or that physical objects exist. Without this knowledge we
don’t know that perception and reason are reliable cognitive processes. However, this misses the point, as it assumes
that which the reliabilist rejects, justification. For the reliabilist we don’t need to know that reason or perception are
reliable cognitive processes to possess knowledge. If they are, then we do; this isn’t a matter of justification, but
what is the the case. Thus, all sceptical arguments challenging perception or reason as adequate justifications for
knowledge are irrelevant, and the reliabilist can resist global scepticism.
However, despite its initial promise, we have good reason to reject the reliabilist response as its definition of
knowledge falls foul of Gettier examples. For example, in Gettier’s second example we can assume that Smith used
reliable cognitive processes (e.g., perception and reason) to form his true belief ‘Jones has a Ford or Brown is in
Barcelona’, and Harry used a reliable cognitive process (perception) to form his true belief ‘There is a barn’, but in
both cases – due to the role of luck and coincidence – we are reluctant to say the agent knew the proposition. Thus,
yes, reliabilism resists global scepticism if we accept its definition of knowledge, but inconveniently Gettier examples
reveal we should do no such thing, and therefore reliabilism fails to resist global scepticism.
Turning to empiricism there are two ‘judgments of reason’ we can know: relations of ideas (analytic truths) and
matters of fact (synthetic truths). The former is known a priori by analysing the meaning of words, and the latter is
known a posteriori from perceptions (both from reflection and the senses). If we start with the former, it would
appear that empiricism is on to a winner. Surely, we cannot doubt that all triangles have three sides or that a
bachelor is an unmarried man. They are true by definition and cannot be denied without falling into logical
contradiction. Our knowledge of them is certain.
However, if we take Descartes’ evil demon hypothesis seriously a doubt may enter which cannot be banished. For if
as Descartes suggests an evil demon exists and he has complete control of my mind, not just in terms of what I
perceive but also what I think, then how can I be certain that the demon is not making me think that a triangle has
three side when in fact it does not. With such control, what seems obvious, certain, true by definition, may actually
be far from it. This is difficult prospect to consider, but without any guarantee that our minds are not being
