A little while back, we came to the defense of Arthur Conan Doyle by pointing out that surprisingly many intellectuals and scientists including those of the caliber of Albert Einstein and Pierre Curie, believed in or were at least open to the possibility of the paranormal back in the late 19th and early 20th centuries, and that these beliefs were far more defensible 120 years ago than they are today.
Curie had company. William Crookes and fellow Nobel laureate Charles Richet were two of the many scientists who devoted a large part of the time to paranormal research. Albert Einstein wrote the preface to Mental Radio. Respected publications published serious discussions about psychic and supernatural phenomena. Not everyone was a believer, but it was rare to find people in the "absolutely, positively no-way" camp either.
Nor were the Curies the only ones to make a connection between the fantastic scientific discoveries of the day and the possibility of the paranormal. When Edison stumbled on the first radio transmitter back in the 1870s (that’s another story we need to get into), he wondered if it might explain telepathy. When the later debunked N-rays were announced, scientists speculated that they too might explain psychic phenomena.
When you are constantly bombarded with news of the seemingly magical—be it cylinders that capture voices, strange rays that let doctors see through flesh, or communications that somehow travel instantly through the air—it would probably seem foolhardy to prematurely dismiss the possibility of something outside of our range of knowledge.
We, on the other hand, have two large bodies of knowledge to draw on when evaluating claims of the supernatural. First, we have well over a century of paranormal research where, when you take out the frauds and the fatally flawed test designs, you find no support whatsoever for these claims. Second, we have a century of research into physics that has effectively ruled out any possibility of these forces causing ghosts to walk or psychics to tell you anything that couldn't be learned from a cold reading.
This still didn't explain why someone would still be making these claims in the middle of the last century:
‘I assume that the reader is familiar with the idea of extra-sensory perception … telepathy, clairvoyance, precognition and psycho-kinesis. These disturbing phenomena seem to deny all our usual scientific ideas … Unfortunately the statistical evidence, at least for telepathy, is overwhelming … Once one has accepted them it does not seem a very big step to believe in ghosts and bogies.’
These words weren’t published in the pages of an obscure occult journal or declared at a secret parapsychology conference. They weren’t written by a Victorian spiritualist or a séance attendee. In fact, their author is Alan Turing, the father of computer science, and they appear in his seminal paper ‘Computing Machinery and Intelligence’ (1950), which describes the ‘imitation game’ (more commonly known as the ‘Turing test’) designed to establish whether a machine’s intelligence could be distinguished from that of a human.
The paper starts by setting up the now-famous thought experiment: a human, a machine, and an observer who asks questions. If the observer cannot work out which one is which based on their responses, the machine has passed the test: its intelligence is indistinguishable from that of a human mind. The vast majority of the paper addresses various objections against the experiment from mathematics, philosophy of mind, or from those sceptical about the power of computers.
But, about two-thirds of the way through the paper, Turing addresses an unexpected worry that might disrupt the imitation game: telepathy. If the human and the observer could communicate telepathically (which the machine supposedly could not do), then the test would fail. ‘This argument is to my mind quite a strong one,’ says Turing. In the end, he suggests that, for the test to work properly, the experiment must take place in a ‘telepathy-proof room’.
Why did Turing feel the need to talk about telepathy? Why did he consider extrasensory perception a serious objection to his thought experiment? And what about his peculiar mention of ghosts?
Matyáš Moravec, a lecturer in philosophy at Queen’s University Belfast, explains that Turing's beliefs may have been questionable at the time, they weren't all that unconventional in the mid-century halls of Cambridge.
In 1882, a group of scholars associated with Trinity College, Cambridge,
founded the Society for Psychical Research, a learned society whose aim
was to study these phenomena with scientific rigour. Over the course of
its existence, the society counted among its members some of the
brightest minds of the time, including the author Arthur Conan Doyle and
the physicist J J Thomson. Its members
displayed various levels of commitment to the phenomena of the séance
room. Some were very committed, such as the physicist Oliver Lodge, who
wrote a highly influential book containing records of séances where he
communicated with his son who was killed in action during the First
World War. Some were much more sceptical, like Eleanor Sidgwick, a
physics researcher and the principal of Newnham College, Cambridge, or
John Venn, the inventor of the Venn diagram. Despite the differences in
their level of commitment to the reality of paranormal occurrences, this
heterogeneous group of scholars agreed that these phenomena deserved
scholarly attention.
A high number of professional philosophers either joined the society or
engaged with its findings. The ethicist Henry Sidgwick (Eleanor’s
husband) was one of its founders, together with F W H
Myers, the inventor of the word ‘telepathy’ and an unusually committed
member: according to at least one report, he continued his involvement
after his death, sending messages from the beyond via various mediums (a
sort of extreme version of the professor emeritus who occasionally
drops by the department). Such esteemed philosophers as Henri Bergson, William James and F C S Schiller were each elected president of the society. Many other philosophers, such as May Sinclair, were regular members.
...
Serialism begins with the premise that anything that moves must move in time. For example, a car moving on a road is in one place at t1, and at another place further up the road at t2. If there was no time, it would be hard to describe the car as ‘moving’ at all. But, Dunne argued, time itself
moves. It would be strange to say that time does not move. It cannot
stand still. (The British philosopher Antony Flew noted that Dunne does
not distinguish straightforward spatial motion from the elusive ‘flow’
of time, which is the main blunder that eventually leads to his bizarre
theory of time.) So, Dunne thought, there must be a meta-time or
hypertime, a higher series of ‘time above time’ describing the movement
of the time we inhabit. But this ‘time above time’ must also move
(otherwise it would not be time). So, there must be a third series of
time, and so on to infinity. Dunne believed that, when we dream, our
minds can gain access to these higher series of times, some of which
contain future events.
The book became a bestseller. It was republished in several editions and influenced several key 20th-century writers, including Jorge Luis Borges, C S Lewis, J B Priestley and J R R
Tolkien. The physicist Arthur Eddington wrote an approving letter to
Dunne, which was published in later editions of the book. The wider
public became fascinated with the idea of ‘seeing the future’, to the
point where the phrase ‘Dunne dream’ became a shorthand for any
precognitive dream.
By contrast, the book was ridiculed in academic circles. Not so much
because Dunne believed in precognitive dreams (as a matter of fact, many
academics thought that the catalogue he provided of these dreams was
the only valuable thing about his book [This strikes me as particularly significant. Lots of intellectuals accepted the idea that precognition was real of needed to be studied; they were just skeptical of that particular explanation. -- MP]), but because of his bizarre
theory of time. One reviewer in The Journal of Philosophy said that it was very hard to take it seriously, another in Nature
considered the possibility that the book was just a practical joke, and
an unimpressed philosopher called serialism a ‘logical extravaganza’.
Broad was the only professional philosopher to seriously engage with
Dunne. Trinity College holds Broad’s own copies of Dunne’s books, whose
margins are covered in extensive notes containing suggestions for fixing
serialism and using it to generate a philosophically robust explanation
of precognitions. He even published a stand-alone paper on Dunne in the
journal Philosophy in 1935, and Dunne features in several places of his magnum opus, Examination of McTaggart’s Philosophy (1933-8).
Broad addressed what might be called the ontological problem with precognitions. In the first half of the 20th century,
one of the most widely accepted views of time was the ‘growing block’
theory, which says that the past exists, the present exists, but the
future does not. This accords pretty well with our everyday intuitions
about time, but poses a particular philosophical problem for the
existence of precognitions. Say I foresee, in a dream, what happens next
Saturday. Supposing the growing-block theory is true, next Saturday
does not (yet) exist. So, what was it that I saw in the dream? How could
I have seen something that does not exist?
The engagement with Dunne motivated Broad to propose one of the first
‘hypertime’ theories. This is a group of theories that claim that time
has two (or more) dimensions, similar to the way that the space we
inhabit is three-dimensional. In Broad’s view, one dimension had a
growing-block structure. In this dimension, the future does not exist.
But, he suggested, there could also be a second dimension of time in
which the future does exist, and so contains the foreseen
event. In a precognitive dream, we gain access to it. This is a
streamlining of Dunne’s logical extravaganza: Broad got rid of the idea
that time itself must move through time, and ditched the ‘infinite’
series of dimensions. Two dimensions are enough.