A Device-Oriented Defi nition of Functions of Artifacts and Its Perspectives 217
an agent such as the high-conductivity property, the property of an operand can enable a
behavior and/or a function: “The combustible property of oil enables the burning behavior
of a boiler (and a heat-generation function)” (operand’s property enabling [quasi-]
function). Especially for human actions, we can say “a property of a tool enables human
actions” such as “the sharp edge of a knife enables a human’s cutting action” (user enabling
[quasi-]function). This can be defi ned as a user enabling function, as a subtype of envi-
ronmental functions.
A capability function represents that an entity can perform an activity that has no effect
on others. For example, we may say, “Humans have a walking function” (capability func-
tion). The property enabling function and capacity to perform a function are similar, but
they are based on the effect on other external entities. Last, we should note that the func-
tions with designing time discussed in section 12.3.5 are quasi-functions as well.
12.4 Concluding Remarks
We discuss device-oriented defi nitions of functions of technical artifacts and some general
categories of functions from different perspectives for capturing functions. Table 12.1
shows a summary of some of the distinctions discussed in this chapter, though it does not
include detailed descriptions about some of the distinctions in section 12.3. From the
viewpoint of engineering, we emphasize accidental functions based on contexts of acci-
dental use and that our defi nition of function is separate from a device ( function as role
of behavior).
Table 12.1
Summary of Distinctions of Functions
Distinction Distinguished types of functions (F denotes “function”) Section
locality local F and conjunct F 12.2.2
context determiner external F and component F 12.2.3
inherence F as role of behavior and capacity to perform a function 12.2.4
essentiality essential F and accidental F 12.2.5
generality (type) generic F (types of F) and instances of F 12.2.7
achievement goal F and method F 12.2.7
system boundary device F and environmental F 12.3.3
effect effect F and quasi-F 12.3.3, 12.3.6
device’s operand base-F and (causal) meta-F 12.3.4
operand (meta effect) effect-on-state F and effect-on-process F (meta F) 12.3.4
negation of goal positive F and negative F 12.3.5
— other functions in fi gure 12.3 12.3