{"id":20,"date":"2000-12-20T00:00:29","date_gmt":"2000-12-20T07:00:29","guid":{"rendered":"http:\/\/www.mii.ucla.edu\/causality\/?p=29"},"modified":"2000-12-20T00:00:29","modified_gmt":"2000-12-20T07:00:29","slug":"is-the-dox-operator-universal","status":"publish","type":"post","link":"https:\/\/causality.cs.ucla.edu\/blog\/index.php\/2000\/12\/20\/is-the-dox-operator-universal\/","title":{"rendered":"Is the do(x) operator universal?"},"content":{"rendered":"<p>From <font><strong>Bill Shipley, Universite de Sherbrooke, (Quebec) CANADA: <\/strong><\/font><\/p>\n<p>I<font>n most experiments, the external manipulation consists of adding (or subtracting) some amount from <em>X<\/em> without removing pre-existing causes of <em>X<\/em>.  For example, adding 5 <em>kg<\/em>\/<em>h<\/em> of fertilizer to a field, adding 5 <em>mg\/l<\/em> of insulin to subjects etc.  Here, the pre-existing causes of the manipulated variable still exert effects but a new variable (<em>M<\/em>) is added.<br \/> &#8230; The problem that I see with the <em>do<\/em>(<em>x<\/em>) operator as a general operator of external manipulation is that it requires two things: (1) removing any pre-existing causes of <em>x<\/em> and (2) setting <em>x<\/em> to some value.  This corresponds to some types of external manipulations, but not all (or even most) external manipulations.  I would introduce an <em>add<\/em>(<em>x=n<\/em>) operator, meaning &quot;<em>add<\/em>, external to the pre-existing causal process, an amount &#39;<em>n<\/em>&#39; of <em>x<\/em>&#39;&#39;. Graphically, this consists of augmenting the pre-existing causal graph with a new edge, namely <em>M-n<\/em>&#8211;&gt;<em>X<\/em>. Algebraically, this would consist of adding a new term &#8211;<em>n<\/em>&#8211; as a cause of <em>X<\/em>.<\/font><\/p>\n","protected":false},"excerpt":{"rendered":"<p>From Bill Shipley, Universite de Sherbrooke, (Quebec) CANADA: In most experiments, the external manipulation consists of adding (or subtracting) some amount from X without removing pre-existing causes of X. For example, adding 5 kg\/h of fertilizer to a field, adding 5 mg\/l of insulin to subjects etc. Here, the pre-existing causes of the manipulated variable [&hellip;]<\/p>\n","protected":false},"author":3,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[12],"tags":[],"class_list":["post-20","post","type-post","status-publish","format-standard","hentry","category-do-calculus"],"_links":{"self":[{"href":"https:\/\/causality.cs.ucla.edu\/blog\/index.php\/wp-json\/wp\/v2\/posts\/20","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/causality.cs.ucla.edu\/blog\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/causality.cs.ucla.edu\/blog\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/causality.cs.ucla.edu\/blog\/index.php\/wp-json\/wp\/v2\/users\/3"}],"replies":[{"embeddable":true,"href":"https:\/\/causality.cs.ucla.edu\/blog\/index.php\/wp-json\/wp\/v2\/comments?post=20"}],"version-history":[{"count":0,"href":"https:\/\/causality.cs.ucla.edu\/blog\/index.php\/wp-json\/wp\/v2\/posts\/20\/revisions"}],"wp:attachment":[{"href":"https:\/\/causality.cs.ucla.edu\/blog\/index.php\/wp-json\/wp\/v2\/media?parent=20"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/causality.cs.ucla.edu\/blog\/index.php\/wp-json\/wp\/v2\/categories?post=20"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/causality.cs.ucla.edu\/blog\/index.php\/wp-json\/wp\/v2\/tags?post=20"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}