Paralysis by Lucrezia Dal Toso

The dualism of Popper-Eccles
That of mind/body interaction is a traditional problem of philosophical
reflection. The development of new scientific disciplines today tends to propose
it again as a problem of the relationship between the mind - or self-awareness -
and the brain.
The most authoritative exponents
of the dualist model are the
philosopher Karl Popper (1902-
94) and the neurobiologist and
Nobel Prize winner John Eccles
(1903-97). Their thesis (The self and
its brain, 1977) is that the mind,
self-conscious thought, is an entity
ontologically distinct from brain
matter and is able to influence it
causally. Eccles identifies in the
left frontal cortex of the human
brain some microstructures, called
“psychons”, which would have the
function of communicating to the
brain the “wishes” of the conscious
mind (his critics will compare them
with irony to Descartes’ pineal
gland). Popper frames Eccles’
discoveries in a broader theoretical
paradigm, called “Three Worlds
Theory”, which assumes a complex
model of interaction.
The self and his brain
The core of the mind/brain problem is the
qualitative difference and categories between the
nature of brain structures and processes and the
nature of mental objects and processes.
What is the relationship between mental activity
and the electrical and chemical activation of a
certain number of brain cells? In what sense can
one say that a thought or emotion depends on
the brain?
In particular, the conscious self is a phenomenon
that is difficult to reduce to a set of brain
processes, just as the intentionality of mental
acts (which allows us to think both real and
unreal objects) is difficult to explain as a material
epiphenomenon.
Schematically, two main models of solution can
be distinguished: a dualist and interactionist
model and a monist and materialist model.
The 3-Worlds Theory of Popper
Most people would easily agree that the scientific method is not the only way to
bring about knowledge.
Popper distinguishes, at the level of
regional ontologies, three worlds:
World 1, consisting of matter
and physical processes; World 2,
consisting of mental states; World
3, consisting of the products of the
human mind (abstract concepts,
scientific theories and other
cultural objects). No purely physical
system can grasp the abstract
contents of World 3. Therefore
there must be mental activities
(World 2) that grasp the objects of
World 3 and then interact causally
with the events of World 1.
Critics have objected that if
electronic computers can simulate
thought, and if the brain is a
“biological machine” that functions
like a computer, we would have
an example of direct interaction
between World 1 and World 3.
Popper counter-objectioned that
this is only an analogy and not an
appropriate account of how the
principles of World 3 (including
logic) govern the activities of
World 1.
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