{"id":10509,"date":"2011-07-24T17:37:30","date_gmt":"2011-07-24T17:37:30","guid":{"rendered":"https:\/\/maverickphilosopher.blog\/index.php\/2011\/07\/24\/leibnizs-law-a-useless-expression\/"},"modified":"2011-07-24T17:37:30","modified_gmt":"2011-07-24T17:37:30","slug":"leibnizs-law-a-useless-expression","status":"publish","type":"post","link":"https:\/\/maverickphilosopher.blog\/index.php\/2011\/07\/24\/leibnizs-law-a-useless-expression\/","title":{"rendered":"‘Leibniz’s Law’: A Useless Expression"},"content":{"rendered":"

Pedant and quibbler that I am, it annoys me when I hear professional philosophers use the phrase 'Leibniz's Law.'  My reason is that it is used by said philosophers in three mutually incompatible ways.  That makes it a junk phrase, a wastebasket expression, one to be avoided.  Some use it as Dale Tuggy does, here<\/a>, to refer to the Indiscernibility of Identicals, a principle than which no more luminous can be conceived.  (Roughly, if a<\/em> = b<\/em>, then whatever is true of a<\/em> is true of b<\/em>, and vice versa.)  Fred Sommers, referencing Benson Mates, also uses it in this way.  (See The Logic of Natural Language<\/em>,  p. 127)<\/span><\/p>\n

Others, such as the distinguished Australian philosopher Peter Forrest, use it<\/a> to refer to the Identity of Indiscernibles, a principle rather less luminous to the intellect and, in my humble opinion, false.  (Roughly, if whatever is true of a<\/em> is true of b<\/em> and vice versa, then a<\/em> = b<\/em>.)  And there are those who use it as to refer to the conjunction  of the Indiscernibility of Identicals and the Identity of Indiscernibles.<\/span><\/p>\n

So 'Leibniz's Law' has no standardly accepted usage and is insofar forth useless.  And unnecessary.  You mean 'Indiscernibility of Identicals'?  Then say that.  If you mean its converse, say that<\/em>. Ditto for their conjunction.<\/span><\/p>\n

There is also the problem of using a great philosopher's name to label a principle that the philosopher may not even have held.  Analytic philosophers are notorious for being lousy historians.  Not all of them, of course, but the run-of-the-mill.  If Sommers is right, Leibniz was a traditional logician who did not think of identity as a relation as Frege and Russell do.  (p. 127) Accordingly, 'a = b' as this formula is understood in modern predicate logic does not occur in Leibniz. <\/span><\/p>\n

 <\/p>\n","protected":false},"excerpt":{"rendered":"

Pedant and quibbler that I am, it annoys me when I hear professional philosophers use the phrase 'Leibniz's Law.'  My reason is that it is used by said philosophers in three mutually incompatible ways.  That makes it a junk phrase, a wastebasket expression, one to be avoided.  Some use it as Dale Tuggy does, here, to refer … Continue reading “‘Leibniz’s Law’: A Useless Expression”<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[454,346,6,723,20],"tags":[],"class_list":["post-10509","post","type-post","status-publish","format-standard","hentry","category-history-of-philosophy","category-identity-and-individuation","category-language-matters","category-leibniz","category-metaphilosophy"],"_links":{"self":[{"href":"https:\/\/maverickphilosopher.blog\/index.php\/wp-json\/wp\/v2\/posts\/10509","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/maverickphilosopher.blog\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/maverickphilosopher.blog\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/maverickphilosopher.blog\/index.php\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/maverickphilosopher.blog\/index.php\/wp-json\/wp\/v2\/comments?post=10509"}],"version-history":[{"count":0,"href":"https:\/\/maverickphilosopher.blog\/index.php\/wp-json\/wp\/v2\/posts\/10509\/revisions"}],"wp:attachment":[{"href":"https:\/\/maverickphilosopher.blog\/index.php\/wp-json\/wp\/v2\/media?parent=10509"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/maverickphilosopher.blog\/index.php\/wp-json\/wp\/v2\/categories?post=10509"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/maverickphilosopher.blog\/index.php\/wp-json\/wp\/v2\/tags?post=10509"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}