Re: Model != World?
From: Jan Hidders <hidders_at_gmail.com>
Date: Mon, 4 Jan 2010 14:33:12 -0800 (PST)
Message-ID: <669629c5-5dc0-48a9-9eae-7591c5c4c432_at_a32g2000yqm.googlegroups.com>
Date: Mon, 4 Jan 2010 14:33:12 -0800 (PST)
Message-ID: <669629c5-5dc0-48a9-9eae-7591c5c4c432_at_a32g2000yqm.googlegroups.com>
On 4 jan, 22:44, Tegiri Nenashi <tegirinena..._at_gmail.com> wrote:
> Excuse me, but I have a basic question. What is the motivation for
> differentiating the concepts of "World" and "Model"?
The term model is usually used for the complete structure for which we define the truth value of a formula. In conventional logic this is usually a model of the particular world we assume we are in. However, in modal logic this includes the complete set of possible worlds plus the particular world we assume we are in. Both are needed since for basic propositions we need to inspect the actual world and the modal operators refer also to the other possible worlds.
- Jan Hidders