15 January 2015

Toward an Understanding of the Mind: We Think in Metaphors

Traditional philosophies of mind have held several tenets about the nature of human reason. A (very) abridged list:

  • Reason is literal, abstract, and fundamentally unembodied. This does not mean that we don't take in sensory data from our bodies to think; rather, it means that the process of reasoning is not fundamentally connected to our embodiment, such as the contemplation of abstract forms. 
  • Reason is primarily conscious, and we can understand our minds through critical self-reflection.
  • Metaphor is primarily poetic and rhetorical, and not part of everyday language or fundamental to our process of reasoning.
The findings of cognitive neuroscience reveal all of these tenets, and many more, to be flatly and irreparably wrong. Cognitive neuroscience reveals that:
  • Reason is almost entirely subconscious, and is structured by metaphors.
  • These metaphors are physical connections in the brain which depend on our embodiment.
  • We cannot choose which metaphors structure our process of reasoning.
To understand how we think in metaphors, it's helpful to first understand what parts of our cognition are not metaphorical. Quite a bit of our conscious experience is indeed literal: these are spatial-relations concepts like up, down, over, under, through, left, right, etc.; proprioceptive concepts like reaching, touching, feeling, listening, seeing, tasting, etc.; and structural concepts like more, less, wider, narrower, etc. Notably, all of these aspects of cognition are directly tied to our embodiment. This is a key concept that will be expanded upon shortly.

These literal concepts form the skeletal structure of metaphorical reasoning, which is part of our everyday language and absolutely fundamental to the process of reasoning itself. One of the most striking finding of cognitive science is that it is virtually impossible for us not to think in metaphors. The most basic of these metaphors are called primary metaphors, in which a sensorimotor operation is paired with a subjective experience. Importantly, these primary metaphors are physical connections in the brain. I'll give just a few examples:

1. Love is closeness
It was a difficult time for us, but ultimately my wife and I have grown closer to each other
They were best friends for years, but recently have drifted apart

2. More is bigger
He's got a huge ego
The store had a big sale yesterday

3. Knowing is grasping
That flew over my head
Ah, now I've got it

Importantly, these metaphors are also frequently paired with physical gestures. These types of gestures transcend language and are found throughout the human experience. For example, if you said, "prices went through the roof" and pointed sideways, your audience would be confused about your meaning. Intuitively, you point upward. You wouldn't pair saying "Ah, now I've got it" with a waving of your hands in the air; you'll gesture with a closing fist as though physically grasping an object. If someone asks you how much you like cookies, you won't say "I love them!" while moving your hands close together; you'll stretch your arms out wide! All human beings use these same primary metaphors, regardless of language.

The formation of these primary metaphors happens very early in our childhood, as two different regions of the brain are repeatedly activated simultaneously. For the "love as closeness" metaphor, a child experiences the physical sensations of affection — being gently touched, held, kissed, etc., with spatial proximity. Again, physical gestures become important; we don't say "I love you" while pushing someone away; we usually say the word while hugging, touching, etc. This metaphor becomes a permanent connection in the brain and is used throughout our lives in narratives about loving relationships. 

The statement that this is a physical connection in the brain is not something can be swept under the rug (that's a metaphor) by claiming it's a fortunate correlation. This is because scientists who study embodied cognition successfully predicted that the neural circuitry responsible for sensorimotor perception was the same circuitry responsible for the formation of primary metaphors [1].  

A profoundly important aspect of this development is that the formation of these primary metaphors is entirely subconscious. You did not have any say over what metaphors structure your language and process of reasoning. We use primary metaphors with regard to time ("my birthday is just around the corner", "I'm glad that situation is behind me"), causation ("the President got the country through a tough economic time"), and countless other everyday processes of reasoning and language. 

So to recap, the findings of cognitive neuroscience are that:
  • Reasoning and language are structured by primary metaphors
  • Primary metaphors are physical connections in the brain
  • The formation of primary metaphors is entirely subconscious
  • Thus, the structure of reason is subconscious and inaccessible to our phenomenological experience — you cannot understand your own mind just by thinking about it!
These findings undermine a great deal of philosophical assumptions that have stubbornly persisted for centuries and are only now dying a slow death, being replaced by an empirically responsible philosophy of mind. Philosopher of antiquity, without the access to the empirical methodology we have today, could only attempt to understand their minds through self-reflection. But since that is impossible, those philosophies were doomed from the outset.

Next, we'll take a look at some of that philosophy of mind, particularly in regard to Aristotle's view of abstract thought, and show how computational neuroscience usurps it. 

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