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there is always more to having those abilities than knowing those facts.
(Mellor 1991c: 7)
But if the ability hypothesis is false, then it cannot explain why Nagel is
wrong about the  factual scope of objective science . Indeed, it seems rather
that there are facts about the bat s experience (assuming it has experiences)
which are beyond the scope of objective science: the facts which would be
truly expressed (per impossibile) by saying  Experiencing the world from a
sonar point of view is like this . Or, to take a more everyday example, the fact
Subjective facts 73
that I can express when I say  red looks like this is a fact that a blind person
cannot know. Yet, as Russell (1927) points out, a blind person can know the
whole of physics. And there is nothing relevant to this debate which stops the
blind person learning the whole of objective science. True enough, the sighted
person has abilities that the blind person does not have, and Mellor is right
that no amount of science can give you these abilities. But this is irrelevant.
The important point is not that there are these abilities which someone who
knows what it is like has; the important point is that someone who knows what
it is like knows that certain things are the case. This is the propositional knowledge
which the sighted have and the blind lack, in addition to whatever abilities
they may also have.
4 Challenging the premises
I therefore reject these attempts to dispute the validity of the argument;
the argument is valid. But what about the premises? Few physicalists wish
to challenge the first premise, that in the story as told Mary knows all the
physical facts about colour vision.9 For suppose a physicalist did deny this.
Then her or she would have to accept that there are some physical facts which
in principle cannot be known without having certain experiences. Physics, the
science which states the physical facts, is in principle incompletable until certain
very specific experiences are had. Now it may be true that having knowledge
in general requires having experiences of some kind. Yet how can physical-
ism, which bases its epistemological outlook on physical science, require that
science demands us to have certain specific experiences? The suggestion has
little plausibility.
So most responses to the argument have challenged the second premise
instead, and claimed that Mary does not learn any new fact. In a recent
survey, G�ven G�zeldere describes this character of this dominant response
as follows:
The pivotal issue here is whether the having of an experience constitutes
a special class of irreducible  first-person facts or whether what is lacking
in Mary has to do with her experiential  mode of access to facts that she
is already acquainted with.
(G�zeldere 1997: 38)
The idea seems to be that Mary already knows all the facts in question;
she simply gains a new  mode of access (whatever that is) to a fact she
already knew. If this response were right, then certainly the argument would
be undermined. But it seems to me that, despite its popularity, the response
cannot be correct.
The central idea is that Mary apprehends or encounters in a new way some-
thing she already knew. The phrase  mode of access is often used to describe
what this encountering in a new way is. But what are  modes of access ? One
74 Tim Crane
way to understand them is in terms of new Fregean modes of presentation of the
objects and properties already known under other modes of presentation. On
this interpretation, the puzzle about the argument is of a piece with other
puzzles about intensionality, and many authors have explicitly drawn this
comparison. Vladimir might know that Hesperus shines in the evening but
not know that Phosphorus shines in the evening. We do not conclude from
this that Hesperus is not Phosphorus since, as is well known,  X knows that p
is not an extensional context. According to this view, the fact that Hesperus
shines in the evening is the same fact as the fact that Phosphorus shines in
the evening  after all, they are the same star, the same shining, the same
evening! So although Mary knows that red looks like this, this is not a new
fact that she has learned but, analogously, a new mode of presentation of a
fact she knew before.
But which fact is this? We need to identify something that can be referred
to in more than one way, the relevant fact concerning which can be learned
about in the black and white room. One way of putting it might be like this.
When she leaves the black and white room, Mary judges that seeing red is like
this. The physicalist says that seeing red is being in brain state B, so let us
suppose Mary knew this in the black and white room. Mary can therefore
infer that being in brain state B is like this. We therefore have two terms,
 seeing red and  being in brain state B , that pick out the same thing, and a
predicate  like this which can only be used when one is having the experience.
But nonetheless, the experience is the brain state for all that.
So far so good. But remember that the distinction between different modes
of presentation of the same thing is supposed to show that the second premise
of the argument is false: Mary does not learn anything new. But it cannot show this.
For if this construal of Mary s case and the case of Hesperus and Phosphorus
are really parallel, then this entails that someone who comes to believe that
Phosphorus shines in the evening because of their belief that Hesperus is
Phosphorus does not learn anything new, but only comes to appreciate a
previously known fact under a new mode of presentation. And this cannot be
right: the original point of the distinction between sense and reference was
to do justice to the fact that the discovery that Hesperus is Phosphorus can
be a significant advance in someone s knowledge. It was a discovery about the
heavens that Hesperus is Phosphorus, it was a new piece of knowledge that
the ancients gained. So, similarly, the knowledge that Phosphorus shines in
the evening is a new piece of knowledge. If facts are what you learn when you
gain knowledge, then the normal approach to the distinction between sense
and reference entails that what the ancient astronomers learned when they
learned that Hesperus is Phosphorus is a new fact.
Of course, there is something that is the same before and after this particular
discovery: how things are in the world, the reference of the terms, the entities.
No-one disputes this about the Hesperus Phosphorus case. So one could say:  in
a sense the facts are the same, in a sense they are different . But the relevant
question is whether anything is learned when someone acquires the belief that
Subjective facts 75
Hesperus is Phosphorus, whether there is any new knowledge at all. And if
there is a sense in which the fact learned is a new fact (even if there is a sense [ Pobierz całość w formacie PDF ]