Function (object)

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A Swiss Army Knife has a multitude of functions

The function of an object is the task it has to fulfill. In addition to form , material , structure , etc., function is an essential characteristic of every object that is used or used.


Function can be used as control flow - edge ( relationship will be described between two objects). While the term “ purpose ” describes the motivation for active activity or behavior, the term “function” is usually applied to passive objects that are used by humans. In everyday use, however, function and purpose are often used synonymously. Are used accordingly u. a. the terms method, behavior, action and order.


A heart supplies blood to a body.
An argument is used to substantiate or refute an assertion.
Fe 3 O 4 functions as a catalyst in the Haber-Bosch process .
A residential building is there for living (→ see also: List of buildings by function )
Screws serve as releasable connections of components of all kinds.

The fulfillment of requirements is called functionality or usability .

If an object fulfills several different functions at the same time, one speaks of “multifunctionality”. The goal of covering as many technical functions as possible with as few components as possible is referred to in design engineering as " function integration ". If the target behavior and the actual behavior of an object diverge, one also speaks of overfunction, underfunction, malfunction or error .

Types of functions

In the work Function Statements from 1977, which was picked up several times, Peter Achinstein distinguished between three types of functions with which statements such as "x works as y" can be explicated :

Construction functions

Design capabilities (design functions) describe features that something has been specially created for.


  • A key ring collects several keys and prevents them from being easily lost. That is what it was made for (also).

Usage functions

User functions describe functions that someone (consciously) uses . They can correspond to construction functions, but also - in the sense of the function (s) intended during creation - through misappropriation or improvisation or even with objects that were not made for something, come about without a construction function at all.


  • Someone who uses the keychain precisely for what is conceived uses it for both its functional and its constructional functions.
  • If someone is holding a bunch of keys to keep them from sleeping during the day with the sound of falling down , they are using the key outside of the construction function (s).
    If someone uses iron ore to make a keychain, he / she uses the iron ore for it, but a constructional function of the iron ore is not evident (it was not "made or intended to become a keychain"), unless a strongly teleological position is taken as in the doctrine of predestination .

Service functions

Service functions (service functions) generally describe functions that are actually executed. They can include both construction and utility functions, but also unintended functions that benefit something else.


  • If the key ring is intact and is consciously used in the sense of creation, all three types of function apply to it.
  • When the keychain can no longer perform its construction function due to physical change, but is used as a tool for operating the emergency eject of a CD-ROM drive , there is both a utility and a service function. Here one can still speak of the original construction function, but it can no longer be performed (no longer perform any actual service).
  • If the bunch of keys lies on a sheet of paper and prevents it from being thrown away by a gust of wind without it being put there, then this fastening has a service function that was neither intended nor (consciously) used when it was created.
    If the bunch of keys triggers the arrest of a person wanted by the police in an airport through the signal of a
    metal detector, the bunch of keys had the service function of drawing attention (to the wanted person) from the point of view of the police without it being intended.
    If the frictional noise of the key ring in a jacket pocket leads to the unintentional finding of a desired coin, it also performed a service without a design or utility function.

Philosophical standpoints on the concept of function

In the naturalistic philosophy of the first half of the 20th century, such as logical empiricism or the Vienna Circle , the concept of function was not central. It was viewed as a relic of an Aristotelian teleology or a mere phrase that can be replaced by an equivalent, purely causal formulation. This belief is based on the notion of scientific explanations as expressed in the Hempel-Oppenheim scheme . This strictly reductionist view was represented by Ernest Nagel in his work The Structure of Science (1961).

Since the 1970s in particular, the question of the epistemological position and the peculiarity of the term “function” has come into the interest of philosophical literature: Most contemporary authors start from the idea that the reference to functions wants to explain in a certain way why Object is present in the particular form. This claim is u. a. back to the philosopher Larry Wright . It is philosophically controversial whether the term function has an identical meaning in different disciplines and what this meaning may consist of. Accordingly, it is also controversial whether the type of explanation given for the existence of the functional object can be of the same kind in different sciences. Most authors admit that there are different ways of using the word “function” in different contexts that are not based on a precisely defined term. In biology, theorists of science often relate function to genuinely biological terms such as natural selection ( Ruth Millikan ) or fitness ( John Bigelow and Robert Pargetter ), while in the functions of technical devices and social institutions, human intentions explain the existence of the object.

Robert Cummins sees functions broadly as the roles that certain properties of components play in making a more complex system work. These types of functions are also referred to as causal role functions in the English-language literature . In principle, according to Cummins, functions can be described in any kind of system, even in those in which we would not choose such a formulation in everyday understanding . These include astronomical systems or objects from inanimate nature such as rocks or weather phenomena. The raison d'être of different ways of using the term is acknowledged by Peter Godfrey-Smith , for example , but also by Ruth Millikan.

The question of how functions relate to other terms, such as “ purpose ”, “ design ” or “ organism ”, is also dealt with by various authors.

Individual evidence

  1. Christoph Rehmann-Sutter : Describing life: about interrelationships in biology . Verlag Königshausen & Neumann, Würzburg 1996, pp. 225-227 at Google books , ISBN 3-8260-1189-9
  2. Mohammed Ali Berawi, Roy Woodhead: A Teleological Explanation of the Major Logic Path in Classic FAST . In: 44th Annual Conference of the Society of American Value Engineers International (SAVE International) . Montreal 2004, Function.pdf # page = 3 available on a website of Value Solutions Ltd  ( page no longer available , search in web archivesInfo: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice. (English)@1@ 2Template: Dead Link /