Quantum theory is open to different interpretations, and this paper reviews some of the points of contention.
The standard interpretation of quantum physics assumes that the quantum world is characterized by absolute indeterminism and that quantum systems exist objectively only when they are being measured or observed.
David Bohm’s ontological interpretation of quantum theory rejects both these assumptions. Bohm’s theory that quantum events are party determined by subtler forces operating at deeper levels of reality ties in with John Eccles’ theory that our minds exist outside the material world and interact with our brains at the quantum level.
Paranormal phenomena indicate that our minds can communicate with other minds and affect distant physical systems by nonordinary means.
Whether such phenomena can be adequately explained in terms
of nonlocality and the quantum vacuum or whether they involve
superphysical forces and states of matter as yet unknown to science
is still an open question, and one which merits further experimental
Some of the issues involved are explored below.
An accurate measurement of the position of an orbiting
electron by means of a microscope, for example, requires the use of
light of short wavelengths, with the result that a large but
unpredictable momentum is transferred to the electron. An accurate
measurement of the electron’s momentum, on the other hand, requires
light quanta of very low momentum (and therefore long wavelength),
which leads to a large angle of diffraction in the lens and a poor
definition of the position.
Furthermore, the uncertainty principle implies that a particle can never be at rest, but is subject to constant fluctuations even when no measurement is taking place, and these fluctuations are assumed to have no causes at all. In other words, the quantum world is believed to be characterized by absolute indeterminism, intrinsic ambiguity, and irreducible lawlessness.
As the late physicist David Bohm (1984, p. 87) put it:
Bohm (ibid., p. 95) took the view that the abandonment of causality had been too hasty:
Most physicists, however, are content to accept the
assumption of absolute chance. We shall return to this issue later
in connection with free will.
The wave function can be used to calculate the probability of finding a particle at any particular point in space. When a measurement is made, the particle is of course found in only one place, but if the wave function is assumed to provide a complete and literal description of the state of a quantum system - as it is in the conventional interpretation - it would mean that in between measurements the particle dissolves into a "superposition of probability waves" and is potentially present in many different places at once.
Then, when the next
measurement is made, this wave packet is supposed to instantaneously
"collapse," in some random and mysterious manner, into a localized
particle again. This sudden and discontinuous "collapse" violates
the Schrödinger equation, and is not further explained in the
In fact, the standard interpretation of quantum theory implies that all the macroscopic objects we see around us exist in an objective, unambiguous state only when they are being measured or observed. Schrödinger devised a famous thought-experiment to expose the absurd implications of this interpretation.
A cat is placed in a box
containing a radioactive substance, so that there is a fifty-fifty
chance of an atom decaying in one hour. If an atom decays, it
triggers the release of a poison gas, which kills the cat. After one
hour the cat is supposedly both dead and alive (and everything in
between) until someone opens the box and instantly collapses its
wave function into a dead or alive cat.
more extravagant approach is the many-worlds hypothesis, which
claims that the universe splits each time a measurement (or
measurement-like interaction) takes place, so that all the
possibilities represented by the wave function (e.g. a dead cat and
a living cat) exist objectively but in different universes. Our own
consciousness, too, is supposed to be constantly splitting into
different selves, which inhabit these proliferating,
According to the most extreme, anthropocentric version of this theory, only selfconscious beings such as ourselves can collapse wave functions.
This means that the whole universe must have existed originally as "potentia" in some transcendental realm of quantum probabilities until selfconscious beings evolved and collapsed themselves and the rest of their branch of reality into the material world, and that objects remain in a state of actuality only so long as they are being observed by humans (Goswami, 1993).
Other theorists, however,
believe that nonselfconscious entities, including cats and possibly
even electrons, may be able to collapse their own wave functions
Since the very idea of wave packets spreading out and
collapsing is not based on hard experimental evidence but only on a
particular interpretation of the wave equation, it is worth taking a
look at one of the main alternative interpretations, that of David Bohm and his associates, which provides an intelligible account of
what may be taking place at the quantum level.
assumes the real existence of particles and fields: particles have a
complex inner structure and are always accompanied by a quantum wave
field; they are acted upon not only by classical electromagnetic
forces but also by a subtler force, the quantum potential,
determined by their quantum field, which obeys Schrödinger’s
equation. (Bohm & Hiley, 1993; Bohm & Peat, 1989; Hiley & Peat,
It corresponds to what Bohm calls the implicate order, which can be thought of as a vast ocean of energy on which the physical, or explicate, world is just a ripple.
Bohm points out
that the existence of an energy pool of this kind is recognized, but
given little consideration, by standard quantum theory, which
postulates a universal quantum field -- the quantum vacuum or
zero-point field -- underlying the material world. Very little is
known about the quantum vacuum at present, but its energy density is
estimated to be an astronomical 10^108 J/cm³ (Forward, 1996, pp.
The apparently separate forms
that we see around us are therefore only relatively stable and
independent patterns, generated and sustained by a ceaseless
underlying movement of enfoldment and unfoldment, with particles
constantly dissolving into the implicate order and then
recrystallizing. This process takes place incessantly, and with
incredible rapidity, and is not dependent upon a measurement being
For Bohm, the probabilities calculated from the wave function indicate the chances of a particle being at different positions regardless of whether a measurement is made, whereas in the conventional interpretation they indicate the chances of a particle coming into existence at different positions when a measurement is made.
The universe is constantly defining
itself through its ceaseless interactions -- of which measurement is
only a particular instance -- and absurd situations such as
dead-and-alive cats therefore cannot arise.
He suggests that there may be an infinite series of implicate orders, each having both a matter aspect and a consciousness aspect:
The concept of the implicate domain could be seen as an extended form of materialism, but, he says,
The position that some events "just happen" for no reason at all is impossible to prove, for our inability to identify a cause does not necessarily mean that there is no cause. The notion of absolute chance implies that quantum systems can act absolutely spontaneously, totally isolated from, and uninfluenced by, anything else in the universe.
The opposing standpoint is that all systems
are continuously participating in an intricate network of causal
interactions and interconnections at many different levels.
Individual quantum systems certainly behave unpredictably, but if
they were not subject to any causal factors whatsoever, it would be
difficult to understand why their collective behavior displays
But if this indeterminism is interpreted to mean absolute chance, it would mean that our choices and actions just "pop up" in a totally random and arbitrary way, in which case they could hardly be said to be our choices and the expression of our own free will. Alternatively, quantum indeterminism could be interpreted as causation from subtler, nonphysical levels, so that our acts of free will are caused -- but by our own selfconscious minds.
From this point of view -- sometimes
called "soft determinism" -- free will involves active, selfconscious self-determination.
(1994), for example, who believes that consciousness is basically a
pack of neurons, says that the main seat of free will is probably in
or near a part of the cerebral cortex known as the anterior cingulate sulcus, but he implies that our feeling of being free is
largely, if not entirely, an illusion.
researchers see a connection between consciousness and the quantum
vacuum: for example, Charles Laughlin (1996) argues that the neural
structures that mediate consciousness may interact nonlocally with
the vacuum (or quantum sea), while Edgar Mitchell (1996) believes
that both matter and consciousness arise out of the energy potential
of the vacuum.
He argues that the mind is not only nonphysical but absolutely nonmaterial and nonsubstantial.
if it were not associated with any form of energy-substance
whatsoever, it would be a pure abstraction and therefore unable to
exert any influence on the physical world. This objection also
applies to antireductionists who shun the word "dualist" and
describe matter and consciousness as complementary or dyadic aspects
of reality, yet deny consciousness any energetic or substantial
nature, thereby implying that it is fundamentally different from
matter and in fact a mere abstraction.
According to this view, nature in general, and all the entities that compose it, are formed and organized mainly from within outwards, from deeper levels of their constitution.
This inner guidance is sometimes automatic and passive, giving rise to our automatic bodily functions and habitual and instinctual behavior, and to the regular, lawlike operations of nature in general, and sometimes it is active and self-conscious, as in our acts of intention and volition. A physical system subjected to such subtler influences is not so much acted upon from without as guided from within.
As well as influencing our own brains and bodies, our
minds also appear to be able to affect other minds and bodies and
other physical objects at a distance, as seen in paranormal
These experiments demonstrated that if two quantum systems interact and then move apart, their behavior is correlated in a way that cannot be explained in terms of signals traveling between them at or slower than the speed of light.
This phenomenon is known as nonlocality, and is open to two main interpretations:
If nonlocal correlations are literally instantaneous, they would effectively be noncausal; if two events occur absolutely simultaneously, "cause" and "effect" would be indistinguishable, and one of the events could not be said to cause the other through the transfer of force or energy, for no such transfer could take place infinitely fast.
There would therefore be no causal transmission
mechanism to be explained, and any investigations would be confined
to the conditions that allow correlated events to occur at different
For if nonlocal
propagated not at infinite speeds but at speeds greater than that of
light through a "quantum ether" -- a subquantum domain where current
quantum theory and relativity theory break down -- then the
correlations predicted by quantum theory would vanish if
measurements were made in periods shorter than those required for
the transmission of quantum connections between particles. Such
experiments are beyond the capabilities of present technology but
might be possible in the future. If superluminal interactions exist,
they would be "nonlocal" only in the sense of nonphysical.
already pointed out, if nonlocality is interpreted to mean
instantaneous connectedness, it would imply that information could
be "received" at a distance at exactly the same moment as it is
generated, without undergoing any form of transmission. At most, one
could then try to understand the conditions that allow the instant
appearance of information.
For if ESP
phenomena do involve subtler forms of energy traveling at finite but
perhaps superluminal speeds through superphysical realms, it might
be possible to detect a delay between transmission and reception,
and also some weakening of the effect over very long distances,
though it is already evident that any attenuation must be far less
than that experienced by electromagnetic energy, which is subject to
the inverse-square law.
Bohm says that such foreshadowing takes place "deep in the implicate
order" (Talbot, 1992, p. 212) -- which some mystical traditions
would call the astral or akashic realms.
Experiments at the PEAR lab at Princeton University have yielded a smaller shift of 1 part in 10,000 (Jahn & Dunne, 1987). Some researchers have invoked the theory of the collapse of wave functions by consciousness in order to explain such effects. It is argued that in micro-PK, in contrast to ordinary perception, the observing subject helps to specify what the outcome of the collapse of the wave function will be, perhaps by some sort of informational process (Broughton, 1991, pp. 177-81).
Eccles follows a similar
approach in explaining how our minds act on our own brains. However,
the concept of wave-function collapse is not essential to explaining
mind-matter interaction. We could equally well adopt the standpoint
that subatomic particles are ceaselessly flickering into and out of
physical existence, and that the outcome of the process is
modifiable by our will -- a psychic force.
Such phenomena clearly involve
far more than altering the probabilistic behavior of atomic
particles, and could be regarded as evidence for forces, states of
matter, and nonphysical living entities currently unknown to
science. Confirmation that such things exist would provide a further
indication that within the all-embracing unity of nature there is
Such investigations could
deepen our knowledge of the workings of both the quantum realm and
our minds, and the relationship between them, and indicate whether
the quantum vacuum really is the bottom level of all existence, or
whether there are deeper realms of nature waiting to be explored.