Welcome to the first instalment of the Gibson (1979) reading group. I’m reading this for the first time, so I’m going to take things pretty slowly. If anyone is interested in following along, let me just say that Gibson is surprisingly readable. In this introductory chapter Gibson establishes the importance of the environment to the study of perception. It’s a brief chapter, but I think it’s important enough to leave it on its own.
For animals to exists, they must have somewhere to inhabit. And, for an environment to be an environment (as opposed to just a physical location), it must contain living things. Thus, animals entail environment and vice versa. Animals both perceive and behave in the environment, but that doesn’t mean that they “perceive the world of physics” (p.8). Physics has its units of measurements (e.g., metre, kilogram), but these are arbitrary. In studying perception, it’s important to think about units that are relevant to animals like us. These kinds of units nest within one another. For example, valleys nested within hills, trees and flowers are nested within valleys, leaves are nested within trees, cells are nested within leaves (p.9). These levels are messy and they overlap.
Our perceptual systems are geared towards perceiving things at environmental levels, but they are not geared towards perceiving very large things like galaxies and very small things like atoms. Relative to the range of possible sizes, we are tuned in to a pretty restricted range of medium sized things. This also applies to temporal levels of perception - we can deal with things that last from a second on to many years (but not more than 100 or so). And, it applies to frequencies - we cannot detect either very fast or very slow cycles. The point is that Gibson’s units are conventional and highly personal, while the units of classical physics are arbitrary and impersonal.
When we talk about things persisting in the environment, we mean that some things last a very long time (but, not necessarily that they last forever). What matters is that some things appear to persist to an observer. Solid things are more likely than liquids to persist in a way that is relevant to us. But, if a solid thing disintegrates, then we say that it ceases to exist (although a physicist would say that it has just changed state).
An environment implies a balance between persistence and change. If the world were invariant, then there could be no animals or plants. If the world were always changing, then, well, there also could be no animals or plants because there wouldn’t be anything stable to inhabit.
To reiterate, although environments are bound by the laws of physics, animals don’t perceive the world in these terms. While physics tends to describe the world in terms of bodies in space, it makes more sense to describe the environment in terms of mediums, substances, and surfaces. These concepts are the subject of Chapter 2.