Philosophy of Mind
Substance dualism:
Descartes:
Descartes thought human beings consist of two substances: mental and physical substance.
These substances are “fundamental building blocks of reality”. Physical substance means
extension (size, shape, location in space), while mental substance means thinking
(reasoning, imagining, believing, etc..)
The theory has been proven to be wrong, but Descartes came up with arguments, which
could be strong to some extent anyway.
Descartes’ arguments for substance dualism:
1) Human beings are special because they have reason, language and consciousness
2) Something physical is not conscious, cannot reason or use language
3) Hence, there must be something dividing humans and other physical things:
substance dualism.
Nowadays, these arguments are faced with the challenge whether some physical objects
(animals, AI) have rationality, language and consciousness (stronger nowadays because of
the invention of artificial intelligence, but people remain divided about them being
conscious).
Leibniz’s principle of identity of indiscernibles holds that x = y, but only when x and y share
all their properties. This can be used as a proof for mind-body dualism:
1) I can doubt that I have a body
2) I cannot doubt that I exist
3) Hence, I am not identical to my body
Problems:
Problems with this are that this doesn't seem to work with psychological states, since what
you attribute to something doesn’t automatically mean they are different (one can
differentiate a morning star and evening star even though they are the same star) Thus even
though I can doubt that I have no body, this does not imply that I am not identical with my
body (doubting establishes I have a body) (attribution of qualities can be faulty due to
humans attributing them to things)
Another problem with substance dualism is that a large part of our mental is unconscious,
while impacting our behaviours. It is not clear how Descartes’ theory can take this into
account. Introspection also poses a problem due to it giving us complete mental symmetry
and certainty. In reality however, there might be an asymmetry between how we know
ourselves and others, and how reliable I am about my own mental states (Is knowledge
about my own mental states more certain?)
,Another problem: How is causal interaction between mental and physical substances
possible? The physical domain has causal closure; when we ‘go to the fridge’, we can give a
full physical explanation without referencing the mental. We could call our desires a mental
reference, but those can also be explained by physical means (I want a drink because my
stomach is empty)
Other small issues are that the cartesian account doesn’t explain much while contemporary
neuroscience explains it way better, and it is still unclear what mental substance is anyway
(we only know what it isn’t, e.g.: ‘it doesn’t exist in space’).
There has been a shift towards materialism due to difficulty explaining the place of mental
things in a physical world. To say everything is physical means either materialist principles
are based on current physics, of which we don’t yet know whether they are real, or some
future physics, but these don’t exist yet.
, Behaviorism:
Psychological behaviorism:
Behaviorism is a thesis on how psychology should proceed and focuses on the explanation
of behavior in terms of stimulus-response reactions (objective), and is against internal non-
observable mental states.
This has some problems: Is it wrong to assume non-observable entities exist? By postulating
non-observable entities we can explain things based on that and get further. Also: the
stimulus-response paradigm doesn’t seem to work for complex interactions (When you
‘WOW’ at a Rembrandt, what stimulus is being responded to?), and finally there is the
“poverty of the stimulus argument”.
The poverty of the stimulus argument holds that we need to postulate some innate function
to explain the competence of stimuli in our thought processes.
Philosophical behaviorism:
Philosophical behaviorism is a thesis about the meaning of mental states, and holds that
mental states are behavioral dispositions (toothache pain). These dispositions are
tendencies to display certain behaviour at certain circumstances (disposition to
shatter/dissolve/etc.), but don’t guarantee it will occur, due to it not being the cause. This
way observable behaviour can be used to understand the meaning of mental states.
Ryle: When we talk about the mind, they are reasons about why we behave in certain ways.
Ryle thinks that Descartes got wrong that the mind causes our behaviour; the mind is not a
thing, but a linguistic label.
Problems with this: There is no one-to-one relation between behaviour and mental states:
not everyone expresses toothache-pain in the same circumstances. This means that the
same mental state can lead to different behaviours, meaning we would get an infinitely long
list of all possible behaviours (which would be absurd). This makes philosophical
behaviourism pretty much impossible. One could also pretend to have or not have pain
(super stoic/perfect pretender).
