The explanatory gap (EG) can be defined as the failure to provide an absolute account for mental phenomena. Mental
phenomena are referring to all mental events and states, for example; desires, thoughts
and emotions. A prime focal point is qualia. This is the given term describing
our personal experiences. There is something ‘it is like’ for us when
experiencing things, such as seeing the colour red.
The gap infers a void of important knowledge.
In this case, it is having a verified report detailing qualia in a logical
form. “The explanatory gap argument doesn’t demonstrate a gap in nature, but a
gap in our understanding of nature.” (Joseph Levine). Our curiosity is aimed at increasing our explanatory power of the interactive
relationship between our brain and mind. A well-functioning mind enables us to be
aware of experiences we come across in the world and the reason for our
When defining the
body, we say that it’s physical with precise spatial characteristics. They’re
spatial because they have an exact location. When trying to understand the
mind, our brain is probably the most relevant body part. Our mental character
and brain network are both believed to be independent and interactive states.
This obscure relationship creates inexplicable confusion. The EG expresses a troubling
puzzle associated with our conscious experiences in the material world.
Physicalism states that physical facts metaphysically determine all our facts.
From a posteriori reasoning, we know that physical, non-mental events have the
capacity to cause conscious experiences. On the flip side, it entails that
conscious experiences can cause purely physical events. For example, if I think
about wanting a tea, I can then get up and make one.
Analytical behaviourism may provide solid enough logic to bridge the
explanatory gap. Logical/analytical behaviourism argues that statements of the
mind should be understood in terms of statements about behavioural
dispositions. A disposition is the way in which the mental state is actualised.
When speaking about mental states we are only describing behaviour. For
example, to be in pain is just to wince/cry, etc.
They believe we are misled by the belief that
we have a mind and the way we talk about an individual’s mental states. This
reductive theory argues we should change mental terms such as ‘desiring’ with details
referring to behaviour. Science can only investigate what is observable, hence
we must look to behaviour. Talking about our inner mental states are
inaccessible to others, thus cannot be scientific.
This might bridge the explanatory gap because
the behaviourist says that all psychological phenomena can be translated to
behavioural terms and concepts. They say we don’t need concepts or states which
go further than behavioural dispositions. When talking about mental states we
make a category mistake, said Ryle, meaning we are really talking about some
Emil de Bois-Reymond asked what conceivable link there is between the
movement of atoms in our brain and our ability to experience subjectively. It’s
argued that qualia would not be distinct if they didn’t possess certain
One argument further separating the EG is the
Knowledge argument. Imagine that physicalism is correct and that
neuroscientists had knowledge of all the laws about our functioning brains.
Further, imagine a neuroscientist in possession of this knowledge but was born
without colour perception. Something is missing from their knowledge. For
example, they wouldn’t be able to recognise a red object from a blue one. We
would say that they have learnt something new if he acquired colour perception,
showing that physicalist descriptions can’t explain everything in our world.
Furthermore, he considered the argument from
multiple realizability. This investigates the idea that the same mental state
could be ‘realised’ in different ways. Imagine two people see a bear and are
both terrified. One runs away while the other is frozen to the ground. This
shows that the same mental state could lead to alternative dispositions. This
is problematic because if different behaviours are shown as a cause of the same
mental state, then how can we know they are the same thing. Further, this could
also be true the other way around, i.e. the same behaviour may be shown because
of a different mental state. It follows that if we can’t know that they are the
same thing, there is a gap in our knowledge.
Type identity theory argues that mental states and processes are
identical to brain states and processes. Philosophers such as Smart deny the
existence of irreducible non-physical properties such as qualia. Their claim is
that we have mental ‘types’ of things such as believing something is the case
and we have physical ‘types’ of things, e.g., neurons firing in our brain. The
belief is nothing more than physical processes/changes. The two concepts are
distinct; however, we are referring to the same property.
This is ontological reduction because the
mental phenomena are identical to physical properties. Smart uses Ockham’s
razor to support this. The principle suggests that the simplest answer is
correct as we should avoid multiplying answers beyond necessity. Science has
shown that physical properties of our brains are good reason to explain mental
states. As there are no dualist arguments backed by empirical research, we
should reject theories suggesting non-physical properties exist.
Considering other issues forced upon us by
the explanatory gap, type identity also provides a strong account for mental
causation. If it’s true that all mental properties are identical to brain
properties, then mental states involving behavioural dispositions are
neurological connections. Thus, mental causation is reduced to physical
causation. This can be seen as a step towards bridging the EG.
In ‘What is it like to be a bat’, Nagle argued it’s impossible for us to
acquire an objective understanding of other ‘type’s’ of experiences. Nagle
(1974) defined consciousness as ‘the emergent property making the mind-body
problem intractable’. As organisms have conscious experiences, there is
something that ‘it is like’ for them, the subjective character of experience. He
refuses to say that mental states causing us to behave exhausts their analysis.
We have learnt that bats brains are specially designed to correlate outgoing
impulses with echoes enabling them to judge the distance, shape and size of
objects. We can only imagine how this would feel for us. Our minds capacity is
limited to truly understanding what it’s like for a bat to be a bat.
Regarding personal experiences, we each have
our own point of view. However, we would have as much trouble understanding our
own experiences properly if approached from alternative views as we would if we
tried apprehending experiences of another species without taking up its viewpoint
(Nagle, 1974). It’s this element of experience complexing the problem because real
experiences can only be gained from the organism itself.
In science, reduction is usually seen as progression
towards objectivity as we isolate specific variables, minimising our dependence
on human senses. The less dependent it is, the better the objectivity. However,
with human experiences, movement towards objective descriptions takes us
further away from the phenomenal properties defining their real nature. It is
these factors making the EG difficult to bridge.
Firstly, I outlined analytical
behaviourism which attempts to close the EG by claiming that talk of mental
phenomena is just referring to behavioural dispositions. This was threatened by
issues including multiple realizability. Secondly, I looked at Emil de
Bois-Reymond’s views. He couldn’t conceive how ‘mental’ processes could have a
causal / interactive relationship with the physical world. I moved onto considering mind/brain type
identity theory. This physicalist theory claims that we can close the EG
because brain processes are identical to mental processes. The gap may be
bridged because all that exists are the physical properties. Lastly, we looked
at Nagle’s answer. He believed that the dilemma will continue to exist until
the definitions of key words such as subjectivity and objectivity are agreed.
His claim was that it’s impossible for us to objectively understand other’s
Overall, I believe the explanatory gap is far
from bridged. Problems in this complexing debate evidently exist. Our brains
are so complex that we don’t know everything about them yet. We’ll struggle to understand
the mind properly until we know all physical facts about the way it operates in
life and after death. When defending physicalist theories, phenomenal aspects
of our experience require physical accounts. However, after considering these,
it seems that many questions have remained unanswered.
Chalmers, D. (2010). Consciousness and Its
Place in Nature. The Character of Consciousness, 103-140.
Conaill, D. (2017), Phenomenology,
Objectivity, and the Explanatory Gap. The Sou. Jour. of Phil., 55: 32–50.
Levine, J. (2009). The
Explanatory Gap. The Oxford Handbook of Philosophy of Mind: Oxford University
Nagle, T. (1974). What Is It Like to Be a
Bat? The Philosophical Review, Vol. 83, No. 4, pp. 435-450
Smart, J. “The Mind/Brain Identity
Stanford Encyclopedia of Philosophy (Spring 2017 Edition).
Sturm, T. (2012). Consciousness regained?
Philosophical arguments for and against reductive physicalism. Dialogues in Clinical Neuroscience, 14(1), 55–63.