1. Paavo Pylkkänen
Dept. of Cognitive Neuroscience and Philosophy, Univ. of Skövde, Sweden
Dept. of Philosophy etc., University of Helsinki, Finland
E-mail: paavo.pylkkanen@his.se

2.  Part 1: a brief overview of the philosophical
problems of relating mind and matter
 Part 2: a brief presentation of quantum
theory, leading to Bohm’s interpretation
 Part 3: the relevance of Bohm’s interpretation
to the mind-body problem

4.  Much of contemporary philosophy is
committed to physicalism:
 everything is physical, or
 everything is in an appropriate way dependent
upon the physical (“supervenience”)

5.  Many philosophers find it difficult to simply
reduce the mental to the physical, and they
thus defend non-reductive physicalism:
 mental properties are non-physical properties
which, however, depend or “supervene” upon the
physical.

6.  The trouble with non-reductive physicalism:
it seems to leave the mental causally
inefficacious or epiphenomenal.
 if the mental is non-physical, it seems impossible
to understand how the mental could be the cause
of physical effects
 dependence/supervenience doesn’t help

7.  Philosophers (e.g. Yablo, Lewis, Kim) have
developed some ingenious ways to make the
idea of genuine mental causation plausible.
 however: it seems that even these fail to tell us
how mental properties (conceived as non-
physical) could possibly influence the physical
course of events

8.  There thus seems to be no genuine role for
mental properties in contemporary
physicalism.
 this is a very unsatisfactory situation.
 however, to go back to, say, interactive substance
dualism seems equally unsatisfactory.
 Thomas Nagel has summarized the situation:
“Neither dualism nor materialism seems likely to
be true, but it is not clear what the alternatives
are.”

9.  The alternative explored here: let us look at
science in more detail.
 It has been known for a long time that the
main theories of modern physics, quantum
theory and relativity require radical changes
in our view of matter.

10.  A true “physicalist” needs to consider the
mind-body problem in relation to our best
scientific view(s) about the body
 It could be the case that quantum theory and
relativity say nothing that is relevant to the mind-
body problem
 However, this issue cannot be settled without
careful examination!

19.  What happens if you pass e.g. electrons
through the 2-slits?
 The electron was initially assumed to be a
particle (it has mass and charge)
 So we expect that it should behave like a little
bullet

23.  Notice that we get an interference pattern
even if the electrons enter the slit system one
by one

26.  An individual system exhibits both
 particle properties
▪ it arrives at the detector at a single spot
 and
 wave properties
▪ the place where the spot appears is constrained by the
mathematics of wave behaviour
▪ how else would such individual particles build up a wave
interference pattern?

27.  Natural to ask: how does the electron move
through the slit system? How could a particle
obey the mathematics of waves?
 The easiest way to answer these questions
would be to make further experiments
 “Let’s look what happens”

28.  Unfortunately we cannot observe the motion
of an individual electron in detail!
 This relates to the Heisenberg indeterminacy
principle
 “If we observe precisely where it is, we have no
idea of where it is going” (and vice versa)

29.  Note especially: to predict the movement of
an electron we should measure both position
x (“where it is”) and momentum p (“where it
is going”) at a single moment.
 we cannot do this as long as we stay within current
quantum theory!
 without the initial conditions we cannot predict
what the individual system does!
▪ -> indeterminism, probability…

30.  The mystery is this: the electrons leave as
particles, and they arrive as particles, one by
one, to the screen.
 as a large number of them passes through the
system, a pattern builds up.
 what is this pattern?
 it is an interference pattern!
 interference is a signature of a wave.

31.  But how can the particles, sent into the
system one by one, collectively build up an
interference pattern?
 Surely each individual “particle” must also
have some wave property
 how otherwise could such a “particle” obey the
interference pattern (avoid certain areas)?

40.  Bohm’s interpretation postulates that the
electron is a particle and a field

41.  It is a common strategy in science to
postulate a theory or hypothesis to explain
some phenomena that we are interested in
 “Theorists postulate unobservable entities, and
specific laws governing them, because
occasionally this produces a theory that allows us
to construct predictions and explanations of
observable phenomena hitherto unexplained.”
Churchland 1988: 71

42.  So: Bohm’s interpretation resolves wave-
particle duality by postulating that an
electron is a particle always accompanied and
guided by a new type of field.

43.  In the two-slit experiment the particle goes
through one of the slits, and then appears at a
point in a photographic place
 this explains why we see the appearance of a spot
 note especially that there is no need to assume a
collapse of the wave function
 The accompanying field goes through both slits,
interferes afterwards, and guides the movement
of the particle so that the particles collectively,
spot by spot, build up an interference pattern.

44.  The field gives rise to a new type of potential
energy which Bohm called the “quantum
potential”

47.  Note: R appears both in denominator and
numerator so that it can be multiplied by an
arbitrary constant without changing Q.
 size doesn’t matter here, as a small wave can have
exactly the same effect as a large one!
 this means that Q (and thus the effect on the
particle) can be strong even if the amplitude of the
quantum field is very weak.

48.  What matters then?
 Note that Q depends on the second spatial
derivative of R
 This reflects the way in which R changes, or
the form of the wave.
 Thus, Q depends only upon the form of the
quantum wave!

49.  Bohm & Hiley: the quantum field is not
pushing and pulling the particle mechanically
 Rather, it is putting form into the activity of
the particle, literally IN-FORMING the energy
of the particle
-> A new notion of active information!

50.  The basic idea of active information is that a
form having very little energy enters into a
directs a much greater energy.
 The activity of the greater energy is given a
form similar to that of the smaller energy

51.  Ship on autopilot, guided by a radar wave
 DNA molecule guiding biological processes
 reading a map

52. SHANNON INFORMATION ACTIVE INFORMATION
 A quantitative measure of  Not essentially related to
information that our knowledge or lack of it
represents the way in  e.g. information that is
which the state of a system relevant to determining the
is uncertain to us movement of the electron
itself
 e.g. we can only specify
 information for the electron
probabilities of various states
 information as an “objective
commodity”

53.  As we come to the psychological domain, it
seems obvious that information is a key
factor of mental phenomena.
 this has, of course, been recognized in cognitive
science, with its assumption that the human
brain/mind can be seen as a system that receives
and stores information, and uses such information
in the intelligent control of behaviour.

54.  Bohm’s radical suggestion is that there is at
least a strong analogy between the operation
of information at the quantum level, and the
operation of information at the various levels
of mind.

55.  We saw above that the suggestion is that at
the quantum level information acts – it
actively guides the movement of particles.
 Similarly, in human subjective experience,
information content acts.

56.  When I see something that in a given context
means “danger” (e.g. a snake), this
information content acts within the brain
 via electric action potentials
 also via various neurochemical processes to
prepare the body for appropriate response (cf.
Thagard (2002))

57.  Bohm emphasizes that “…this is not merely a
mental process, but includes an involuntary
and essentially unconscious process of
hormones, heart-beat, and neurochemicals
of various kinds, as well as physical tensions
and movements” (1990).

58.  But how does information content act upon
matter?
 how does such an abstract quality as the
experienced meaning of information (e.g.
“danger”) result in a wide range of electrical and
chemical processes in the brain?

59.  This question is very difficult to answer in
contemporary philosophy of mind, which is
still based upon a very strict division between
the categories “physical” and “mental” (see
Kim 2006).

60.  Meaning is typically considered to be located
at the “mental” side of the division, and there
is currently no coherent theory that explains
how meaning qua meaning can influence
physical processes.

61.  It is assumed that meanings are typically
carried by some physical “vehicles”
 any causal influences associated with meaning are
assumed to be the result of the operation of the
physical vehicle that carries the content or
meaning.
 The meaning itself is assumed to be causally
inefficacious.

62.  Notice that in Bohm’s model of the electron,
the information is carried by the quantum
field that is a qualitatively new type of field in
physics that has some very exotic properties
 influences the movement of particles via its form
 lives in a multidimensional configuration space
 is able to mediate EPR-type non-local influences
between particles

63.  Thus we have a more subtle aspect
(information in the quantum field) guiding
the behaviour of a more manifest aspect (the
particle)

64.  We could generalize this to a principle that
applies whenever meaning influences matter
in other contexts.
 Bohm proposed such a principle and called it
“soma-significance”.
 In this terminology a process in which
meaning organizes the more manifest levels
of matter is called a “signa-somatic” process.

65.  Thus, in the context of the human mind we
could speculate that information contained in
mental processes and conscious experience is
carried by some fairly subtle medium.

66.  Of course, it seems likely that a great deal of
information that enters consciousness is at
some stage carried by neurophysiological
processes that exist at the “classical level” of
reality (i.e. in processes where quantum
effects have a negligible effect).

67.  But it is possible that the information that is
experienced in consciousness is carried by
some much more subtle medium
 analogous to the quantum field
 but capable of much more complex properties,
including qualia, subjectivity and conscious
experience.

68.  This information then typically “acts
downwards” toward the more manifest levels
of the brain, ultimately guiding behaviour.

69.  But how could such a “very subtle” field
carrying information possibly be able to act
upon the more manifest processes e.g. in the
motor cortex?
 one possibility is that it would act via the quantum
field.

70.  “…that which we experience as mind, in its
movement through various levels of subtlety,
will, in a natural way ultimately move the body
by reaching to the level of the quantum
potential and of the ‘dance’ of the particles.
There is no unbridgeable gap or barrier between
any of these levels. Rather, at each stage some
kind of information is the bridge. This implies
that the quantum potential acting on atomic
particles, for example, represents only one stage
in the process.”

71.  Bohm was not too specific about what he
meant by the “various levels of subtlety”.
 Are these new types of fields, similar to but
more complex than the quantum field?
 Or can they include levels of processing in
the more classical domains of brain function
(e.g. the various levels of processing of visual
information).

72.  I think Bohm’s view was quite inclusive
 he did not deny the obvious role which classically
describable processes play in the processing of
information that enters consciousness (see Bohm
& Hiley 1993: 179).

73.  However, I also think he felt that the more
subtle aspects of mind and conscious
experience involve more subtle levels of
information, which have not yet been
discovered by cognitive neuroscience.
 the discovery of the quantum potential is very
important as a first guide to what the nature of
such more subtle levels could be.

74.  Indeed, Bohm suggested that by extending
the ontological interpretation in a natural
way, we could include the subtle mental
aspects into the theory.
 but how can such an extension be done?

75.  “… one could begin by supposing … that as the quantum
potential constitutes active information that can give form
to the movements of the particles, so there is a
superquantum potential that can give form to the
unfoldment and development of this first order quantum
potential. This latter would no longer satisfy the laws of
the current quantum theory, which latter would then be
an approximation, working only when the action of the
superquantum potential can be neglected. Of course,
there is no reason to stop here. One could go on to
suppose a series of orders of superquantum potentials,
with each order constituting information that gives form
to the activity of the next lower order (which is less
subtle).”

76.  This, then, is a schematic view of the way
“mind acts on matter” in Bohm’s extended
ontological interpretation of the quantum
theory.

77.  Bohm’s solution has two parts.
 on the one hand he argues on the basis of
quantum theory that matter has far more
subtle properties than Western mechanistic
science has thus far assumed.

78.  on the other hand he suggests that minds are
very subtle but adds that it is a mistake to
assume that minds are entirely non-physical.
 instead he assumes that every mental process has
a subtle physical aspect which carries the
information that is part of the essence of that
process.

79.  Quantum theory is important even for the
latter hypothesis
 for quantum theory makes plausible the idea that
it is possible for there to exist very subtle physical
processes.
 In Bohm’s extended quantum theory these
physical processes are assumed to be so
subtle that they can justifiably be
characterized as “mental”.

80.  In my view, this is to date the most elegant
attempt to tackle the problem Descartes left
behind himself: how can mind and matter,
which seem so completely different,
nevertheless manage to influence each
other?

81.  Science seeks that which is general and
necessary
 Bohm’s new proposal: information is general
and its action is necessary
-> active information as a universal principle
 Active information helps us to understand the
nature of mind/consciousness
if active information is (part of) the essence of mind,
and if active information is similarly essential in various
levels, all the way to the fundamental laws of physics, it
helps us to find a place for mind in nature!

82.  Bohm, D. (1990) A New Theory of the Relationship of Mind and Matter.
Philosophical Psychology vol. 3 no. 2, pp. 271-286
 Bohm, D. and Hiley, B. J. (1993) The Undivided Universe: An Ontological
Interpretation of Quantum Theory. London: Routledge
 Hiley, B.J. and Pylkkänen, P. (2005), “Can mind affect matter via active
information?”, Mind and Matter, vol. 3, no. 2, 7-26. Url:
www.mindmatter.de/mmpdf/hileywww.pdf
 Pylkkänen, P. (2007) Mind, Matter and the Implicate Order. New York and
Berlin: Springer.
 Towler, M. (2009) Pilot-wave theory, Bohmian metaphysics, and the
foundations of quantum mechanics, a graduate course at the Cavendish
Laboratory, University of Cambridgehttp
://www.tcm.phy.cam.ac.uk/~mdt26/pilot_waves.html
 For criticisms of Bohm’s approach, see the entry “Bohmian mechanics”
by S. Goldstein in the Stanford Enclyclopedia of Philosophy.
 See also Riggs, P. (2009) Quantum Causality: Conceptual Issues in the
Causal Theory of Quantum Mechanics. Heidelberg and New York:
Springer.