鈥淭HE FACT that we can imagine extrasensory perception and the like is
evidence for the fact that they are possible in some sense,鈥� says Tim Crane
(Nature, volume 39, p 685). We are expected to take this assertion
seriously, because Crane is a philosopher at University College London.
But what can he mean? Our imagination is evidence for nothing, except
for the
functioning, or dysfunctioning, of our brain. I am not sure in what 鈥渟ense鈥�
impossible events or phenomena become possible when we imagine them. Throughout
history people have imagined and given meticulous descriptions of unicorns,
dragons, giants, mermaids, gods, devils, angels, heavens that revolve
around the
Earth, and much else, and all to little or no purpose so far as reality
goes.
It is true that certain things have never been observed because they are
statistically improbable, though not absolutely impossible. But it is physical
law, not our imagination, that determines whether a thing is possible. For
instance, it is impossible鈥攏ot merely very unlikely鈥攖hat a heavier
mass will orbit a lighter one. The 鈥渇act鈥� that we can imagine the Sun orbiting
the Earth does not change matters and is not evidence for such a thing
happening. And if parapsychological phenomena are proven to be real 鈥渋n some
sense鈥�, that sense will be external physical law and not because philosophers
and others have been imagining them. This is so obviously the case that only a
philosopher would fail to register it.
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The trouble with philosophers and their intellectual
cousins鈥攑sychologists, sociologists and historians鈥攊s that
when they
write in their knowing way about hard science, they eventually come up against
the problem that trips up all earnest amateurs: the actual facts. It is
rarely a
good idea to write too authoritatively about things we do not know that much
about. But such considerations have seldom restrained philosophers and the like
from attempting to put science in its place. So far as they are concerned, its
place is somewhere where they won鈥檛 be out of their depth.
This is what we might call a philosophical dilemma. Since philosophers
are so
out of their depth with science, any attempt they make to tow it into shallower
waters will be seized upon by scientists and cited as frivolous, uninformed and
unacceptable. And when faced with demands that they prove they know what they
are talking about, before they begin talking about it, philosophers complain
that this puts them in an unfair position. This is not what philosophers do,
they argue. Alas, life is full of injustice and philosophers have to suffer
their share of it with the rest of us.
Modern philosophers are only too happy to remind us that the word
鈥渟肠颈别苍迟颈蝉迟鈥�
was not invented until 1840, and that until then persons who practised science
were known as 鈥渘atural philosophers鈥�. This is unfortunate. For the past two
hundred years or so, since the time of Immanuel Kant鈥攁mong the last
people
to attempt, with some success, to write knowingly about science without first
being trained and educated in it鈥攑hilosophers have been trying to
pull off
the same trick. You could, perhaps, get away with it before then, but you
cannot
now. Science has become too complicated, too full of facts, too diffuse, too
immense.
Between the two world wars there was in Vienna a philosophical debating
society which came to be known as the Vienna Circle. Unlike other such
societies, it had many physicists among its members, and they decided to turn
the tables on philosophers and become scientists who wrote about philosophy.
They went so far as to invent their own philosophy, calling it 鈥渓ogical
positivism鈥�. Sadly, this turned out to be no philosophy at all, but rather a
scientific approach to things. It claimed that people who did not know about
science should not attempt to comment authoritatively on it. Philosophers were
offended by this cavalier attitude.
According to the tenets of logical positivism, anything one can say about
reality is either true, false or metaphysical, that is to say philosophical.
That would seem to leave the field free for philosophising鈥攅xcept that
logical positivists equated 鈥渕etaphysical鈥� with 鈥渕eaningless鈥�. The eminent
physicist Wolfgang Pauli was greatly influenced by the Vienna Circle, and it is
said that he once dismissed a colleague鈥檚 hypothesis as 鈥渘ot even wrong鈥�. Pauli
could be very sarcastic.
Logical positivism faded out as a philosophical school in the 1950s and
1960s, not because it was wrong but because it was too obviously the case.
Meanwhile, philosophers and their ilk continue to be ardent supporters of the
notion that what is real is what happens inside our head. Without our minds,
they say, reality is, at best, a mere possibility waiting to be made real, by a
mind, a thought, a philosopher.
Some day, when philosophers have learnt something about science, who knows
what might happen? It is worth hanging around for, but we should anticipate a
long wait. Philosophers have talked about science for about 2500 years now. Who
can say what another 2500 years might bring?