The Phenomenology of Visual Perception

[DocWatts]

Thought I might post another snippet from my philosophy book, 7 Provisional Truths, for those who might be interested.

This section is a follow up to my earlier post about how Objects are mentally constructed (but not imaginary), where I describe how objects are akin to a lens that our minds use to navigate Reality (which can be found here: https://www.actualized.org/forum/topic/101752-a-framework-for-ontology-objects-are-mentally-constructed/ )

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The Disclosive View As A Window Into Visual Perception

An illustrative case study for how the Disclosive View can help us explain and interpret our embodied interactions with the world can be found in a survey of how our visual field is organized. What we’ll be articulating here is a phenomenological account of how objects are disclosed to us through visual perception (recall that phenomenology concerns itself with how things show up for us in the directness of our lived experience).

Let’s first acknowledge that not having access to eyesight doesn’t preclude an individual from experiencing objects. Minds are inherently adaptable, so a perceptual system without access to eyesight has other avenues for object disclosure, such as touch and sound. For our present purposes however, we’ll focus on the primary means by which objects are disclosed to human beings, which is through vision. For those with functioning eyesight, our perceptual system organizes visual input along a subject-horizon schema. (A schema just refers to a template by which something is organized).

In practice, this subject-horizon schema highlights whatever visual phenomena we happen to be focusing on as a ‘foreground’ (i.e., a subject) which is contrasted against a ‘background’ (a horizon). The boundary that marks where a subject ends and the horizon begins we experience as the edges of an object; be that a blade of grass, or a printed word on a page. For things that extend beyond our field of vision, like the interior of a room, the unified whole that we experience is akin to a mental composite, composed as we move our eyes around, taking in details. 

Crucially, these subject-horizon schemas are not predetermined. Instead, their boundaries have an inherent flexibility that’s dependent upon the context in which we’re viewing something. A well-studied side effect of this flexibility are optical illusions. Optical illusions aren’t a case of our visual system ‘malfunctioning’, as common sense might attest. Instead, they are a consequence of the fact that our sense perception is tailored for coherence and intelligibility; not to recover fixed features from a ‘neutral’ Reality.

While contemporary common sense might tempt us to analogize our visual perception to a video camera, in actuality the embodiment of our minds and our perceptual system tells a very different story. The roots of this misleading metaphor stems from a fundamental misunderstanding of what sense perception is all about. As living beings, our survival depends on being able to flexibly cope with the complexities of a fluid environment. A perceptual system that functioned like a mechanical recording device wouldn’t be up to the task of providing focused information that’s relevant for our needs and purposes. 

The reason that this matters is because the overwhelming majority of what we might potentially encounter within Reality is irrelevant for us. Consequently, our perception is just as much a process of filtering out a near infinite stream of irrelevant stimuli as it is a process of presenting with us sights and sounds and tactile sensations. The fact that your nose isn’t visible to you right now, despite it lying within your visual field, is good evidence of this.

As it turns out, we’re capable of attending to only a tiny part of our visual field at any given moment. While our entire field of view spans about 180 degrees horizontally and 135 degrees vertically, only 2 degrees of that field consists of the highly detailed images that we associate with ‘what it’s like’ to have vision. This high detail portion of your visual field is associated with the fovea centralis, which is the region of your eyes where the light sensitive photoreceptor cells known as cones are most densely packed. From here, the rest of your visual field gradually widens out into a low acuity no man’s land of rough and tumble nebulosity. Where we can’t make out much more than some basic impressions of shapes, colors, and movement. If you doubt this, try affixing your eyesight on a focal point that’s a few inches away from this page, and see if you’re still able to make out any of the words in this paragraph.

It may be a bit surprising to discover just how small a portion of our visual field this high detail focal area actually is. Yet when everything is functioning properly, this system works so well that the blurry no-man’s land which takes up the majority of our visual field isn’t a hindrance to us in practice. In practice, we’re scarcely aware of it most of the time, which is indicative of its efficacy.

Edited June 5 by DocWatts