Where does abstraction collide?

The deliberate suppression of implementation detail so that a system can be used and reasoned about through a simpler description of what it does rather than how it does it: a data type, a function, or a whole layer exposes an interface while its inner workings stay hidden. Kramer's 2007 Is abstraction the key to computing? argued that the capacity to move between levels of detail, and to build and rely on such hidden layers, is the central skill of the discipline. Here the referent is an engineered barrier between an interface and its internals, and it has nothing to do with forming a general idea in the mind, making a non-representational painting, or drawing water from a river.[1]

Unit

One interface that hides a mechanism, defined by what it exposes and what it conceals

Recovery means

Not applicable

Measured by

Judged by how completely the interface hides its internals and by whether the hidden parts can change without breaking users of the interface

The mental process by which a person distils a general category or prototype from many specific examples, keeping what the cases share and dropping what is incidental to any one of them. Posner and Keele's 1968 On the genesis of abstract ideas showed experimentally that people who see only distorted versions of a pattern come to recognise the never-seen central pattern, evidence that the mind builds an abstract summary from instances. Here the referent is a general representation formed inside a learner from particular cases, not a hidden software interface, a style of painting, or the removal of water from its source.[2]

Unit

One general category or prototype distilled from a set of experienced instances

Recovery means

Not applicable

Measured by

Inferred from behaviour, such as faster or more accurate classification of a prototype the learner never actually saw during training

In the theory of visual art, the turning away from faithfully depicting the visible world toward form, colour, and line valued in their own right, up to fully non-representational work. Worringer's 1908 Abstraction and Empathy treated this impulse as a will to abstraction opposed to the urge to reproduce nature, a drive toward flat, stylised, enduring form rather than lifelike likeness. Here the referent is a tendency in how pictures are made and read, a stance toward resemblance itself, and it is unrelated to a software interface, a category held in the mind, or the extraction of water from a source.[3]

Unit

One artwork or style placed by how far it departs from depicting appearances

Recovery means

Not applicable

Measured by

Assessed by critics and historians through the degree of departure from resemblance and the emphasis on form, colour, and line for their own sake

The removal of water from a river, aquifer, or other body for human use, so that the quantity taken over time is what the word names: pumping groundwater for irrigation or supply is the paradigm case. Wada and colleagues' 2010 Global depletion of groundwater resources quantified how the volume abstracted from aquifers worldwide now outpaces natural recharge in many regions. Here the referent is a physical flow of water out of a source, counted in cubic metres or litres per second, and it shares nothing with a hidden software interface, an idea formed in the mind, or a style of picture beyond the letters of the word.[4]

Unit

A volume of water withdrawn from a source over time, in cubic metres or litres per second

Recovery means

The source may recover through natural recharge, but sustained withdrawal beyond recharge depletes it

Measured by

Metered at the point of withdrawal or estimated from pumping records, licensed volumes, and water-balance models