Logic Warning: You are not logged in. Your IP address will be publicly visible if you make any edits. If you log in or create an account, your edits will be attributed to your username, along with other benefits.Anti-spam check. Do not fill this in! ====Logical truth==== {{Main|Logical truth}} Some complex propositions are true independently of the substantive meanings of their parts.{{sfnm|1a1=Hintikka|1y=2019|1loc=§Nature and varieties of logic|2a1=MacFarlane|2y=2017}} In classical logic, for example, the complex proposition "either Mars is red or Mars is not red" is true independent of whether its parts, like the simple proposition "Mars is red", are true or false. In such cases, the truth is called a logical truth: a proposition is logically true if its truth depends only on the logical vocabulary used in it.{{sfnm|1a1=Gómez-Torrente|1y=2019|2a1=MacFarlane|2y=2017|3a1=Honderich|3y=2005|3loc=philosophical logic}} This means that it is true under all interpretations of its non-logical terms. In some [[modal logic]]s, this means that the proposition is true in all possible worlds.{{sfnm|1a1=Gómez-Torrente|1y=2019|2a1=Jago|2y=2014|2p=41}} Some theorists define logic as the study of logical truths.{{sfn|Hintikka|Sandu|2006|p=16}} Summary: Please note that all contributions to Christianpedia may be edited, altered, or removed by other contributors. If you do not want your writing to be edited mercilessly, then do not submit it here. You are also promising us that you wrote this yourself, or copied it from a public domain or similar free resource (see Christianpedia:Copyrights for details). Do not submit copyrighted work without permission! Cancel Editing help (opens in new window) Discuss this page