Answers.Body: <p>Think of a computer as a <a href="https://en.wikipedia.org/wiki/Turing_machine" rel="nofollow noreferrer">Turing Machine</a>--this idea is a <a href="https://en.wikipedia.org/wiki/Model_of_computation" rel="nofollow noreferrer">model of computation</a>, and all of modern computing is based on the <a href="https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis" rel="nofollow noreferrer">Turing-Church thesis</a>.</p>
  
  <p>Machine and program can be interchangeable—at the end of the day, it's all <a href="https://en.wikipedia.org/wiki/Algorithm" rel="nofollow noreferrer">algorithms</a>, whether hard coded in the form of microchip, or in the form of software.  (Any microchip can be emulated as software.)  </p>
  
  <p>Pre-modern computers were mechanical in popular sense. Examples include Babbage's 
   <a href="https://en.wikipedia.org/wiki/Difference_engine" rel="nofollow noreferrer">difference engine</a>, and <a href="https://en.wikipedia.org/wiki/Mechanical_calculator" rel="nofollow noreferrer">mechanical calculators</a> in general.  These led to <a href="https://en.wikipedia.org/wiki/Mechanical_calculator#Programmable_mechanical_calculators" rel="nofollow noreferrer">programmable mechanical calculators</a> and electromechanical computers such as IBM's <a href="https://en.wikipedia.org/wiki/Harvard_Mark_I" rel="nofollow noreferrer">Harvard Mark I</a>, based on Babbage's notion of an <a href="https://en.wikipedia.org/wiki/Analytical_Engine" rel="nofollow noreferrer">Analytic Engine</a>.</p>
  
  <p>In this context, Machine Learning may also connote software that runs on a machine (hardware) as opposed to human/animal learning, which utilizes a biological medium.</p>
  
  <hr>
  
  <p>The etymology of "mechanics", and by extension, "machine" is worth looking at.</p>
  
  <ul>
  <li><a href="http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dmechanisma" rel="nofollow noreferrer">mechanisma</a> (in the sense of "mechanism") </li>
  <li><a href="http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dmechanicus" rel="nofollow noreferrer">mechanicus</a> (in the sense of "belonging to mechanics")</li>
  <li><a href="http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dmechanema" rel="nofollow noreferrer">mechanema</a> (in the sense of "a trick")</li>
  </ul>
  
  <p><em>Mechanema</em> is instructive in that math and engineering can be understood as the "trick to doing things". (<a href="https://www.etymonline.com/word/machination" rel="nofollow noreferrer">Machination</a> is not pejorative in this sense, as "noun of action from past participle stem of <em>machinari</em> 'contrive skillfully, to design; to scheme, to plot,'"—one can plot the course of a celestial body.)</p>
  
  <p><strong>Early uses of the <em>mech-</em> root</strong></p>
  
  <p>Aristotle's <a href="https://en.wikipedia.org/wiki/Mechanics_(Aristotle)" rel="nofollow noreferrer">Μηχανικά</a> (<a href="http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Aristotle/Mechanica*.html" rel="nofollow noreferrer">"Mechanical Problems"</a>*)</p>
  
  <p>Euler's <a href="http://www.17centurymaths.com/contents/euler/mechvol1/preface.pdf" rel="nofollow noreferrer">Mechanica</a> (Euler was referring to <a href="https://en.wikipedia.org/wiki/Classical_mechanics" rel="nofollow noreferrer">Classical Mechanics</a>, an analytic and predictive science made possible by calculus, which is based on functions.)</p>
  
Answers.ContentLicense: CC BY-SA 4.0
Answers.CreationDate: 2019-02-21T01:58:55.780Z
Answers.LastActivityDate: 2019-02-22T01:18:04.333Z
Answers.LastEditDate: 2019-02-22T01:18:04.333Z
Answers.UserDisplayName: DukeZhou
Body: <p>Mitchell's definition of machine learning is as follows:</p>
  <blockquote>
  <p>A computer program is said to learn from experience E with respect to some task T and performance measure P, if its performance at task T, as measured by P, improves with experience E.</p>
  </blockquote>
  <p>Here, we talk about what it means for a <strong>program</strong> to learn rather than a <strong>machine</strong>, but a program and a machine aren't equivalent, so this is a definition about &quot;program learning&quot; rather than &quot;machine learning&quot;. How is this consistent?</p>
  
Tags: <machine-learning><terminology><definitions>
Title: Is the definition of machine learning by Mitchell in his book "Machine Learning" valid?
UserDisplayName: iosdev
ThreadText: # Is the definition of machine learning by Mitchell in his book "Machine Learning" valid?
  
  (Asked by: username_0 on 2019-02-20)
  
  Mitchell's definition of machine learning is as follows:
  
  > A computer program is said to learn from experience E with respect to some task T and performance measure P, if its performance at task T, as measured by P, improves with experience E.
  
  Here, we talk about what it means for a **program** to learn rather than a **machine**, but a program and a machine aren't equivalent, so this is a definition about "program learning" rather than "machine learning". How is this consistent?
  
  **Tags:** machine-learning, terminology, definitions
  
  
  ---
  
  ## 1 answers
  
  ### Answer by username_1 on 2019-02-21. Score: 2
  
  Think of a computer as a [Turing Machine](https://en.wikipedia.org/wiki/Turing_machine)--this idea is a [model of computation](https://en.wikipedia.org/wiki/Model_of_computation), and all of modern computing is based on the [Turing-Church thesis](https://en.wikipedia.org/wiki/Church%E2%80%93Turing_thesis).
  
  Machine and program can be interchangeable—at the end of the day, it's all [algorithms](https://en.wikipedia.org/wiki/Algorithm), whether hard coded in the form of microchip, or in the form of software. (Any microchip can be emulated as software.)
  
  Pre-modern computers were mechanical in popular sense. Examples include Babbage's
  [difference engine](https://en.wikipedia.org/wiki/Difference_engine), and [mechanical calculators](https://en.wikipedia.org/wiki/Mechanical_calculator) in general. These led to [programmable mechanical calculators](https://en.wikipedia.org/wiki/Mechanical_calculator#Programmable_mechanical_calculators) and electromechanical computers such as IBM's [Harvard Mark I](https://en.wikipedia.org/wiki/Harvard_Mark_I), based on Babbage's notion of an [Analytic Engine](https://en.wikipedia.org/wiki/Analytical_Engine).
  
  In this context, Machine Learning may also connote software that runs on a machine (hardware) as opposed to human/animal learning, which utilizes a biological medium.
  
  ---
  
  The etymology of "mechanics", and by extension, "machine" is worth looking at.
  
  * [mechanisma](http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dmechanisma) (in the sense of "mechanism")
  * [mechanicus](http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dmechanicus) (in the sense of "belonging to mechanics")
  * [mechanema](http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.04.0059%3Aentry%3Dmechanema) (in the sense of "a trick")
  
  *Mechanema* is instructive in that math and engineering can be understood as the "trick to doing things". ([Machination](https://www.etymonline.com/word/machination) is not pejorative in this sense, as "noun of action from past participle stem of *machinari* 'contrive skillfully, to design; to scheme, to plot,'"—one can plot the course of a celestial body.)
  
  **Early uses of the *mech-* root**
  
  Aristotle's [Μηχανικά](https://en.wikipedia.org/wiki/Mechanics_(Aristotle)) (["Mechanical Problems"](http://penelope.uchicago.edu/Thayer/E/Roman/Texts/Aristotle/Mechanica*.html)\*)
  
  Euler's [Mechanica](http://www.17centurymaths.com/contents/euler/mechvol1/preface.pdf) (Euler was referring to [Classical Mechanics](https://en.wikipedia.org/wiki/Classical_mechanics), an analytic and predictive science made possible by calculus, which is based on functions.)
  
  
  ---
  
  