Category: uncategorized

For Wittgenstein, what does it mean for two words have the same meaning?

An essential part of Wittgenstein’s later philosophy is the idea that, in general, the meaning of a word is how it used.  Moreover, “how a term is used” amounts to “how it’s use is explained”.

One might say that such a position has problems of a familiar sort. Consider the following argument:

1. A and B are different words.[For example, “car mechanic” and “surgeon”]

2. How A is used=How B is used in virtue of the fact that A and B are explained in the same way.

The mechanic performed surgery on my car this morning.

The doctor performed surgery on my body this morning

3. Therefore, A and B mean the same thing. [they share the same meaning]

3.  If that’s the case, then as long as someone can reasonably explain the meaning of A in the same way as B, then A and B can mean the same thing despite significant differences in

(i) the social environments they were originally (or currently are) used in,

(ii) respective etymologies

(iii) characteristic sensory modality they are appropriate within

Modal logic: developments & applications in IT research areas

This post contains preliminary and very general research into recent developments in nonclassical (i.e. modal) logics and information technology and other relevant areas of study (namely, knowledge representation, computer programming, decision theory, artificial intelligence, verificationism)

A modal logic framework for multi-agent belief fusion

Liau, C. 2005. A modal logic framework for multi-agent belief fusion. ACM Trans. Comput. Logic 6, 1 (Jan. 2005), 124-174. DOI=

Epistemic logic, belief fusion, belief revision, database merging, multi-agent systems, multi-sources reasoning


This article provides a modal logic framework for reasoning about multi-agent belief and its fusion. We propose logics for reasoning about cautiously merged agent beliefs that have different degrees of reliability. These logics are obtained by combining the multi-agent epistemic logic and multi-source reasoning systems. The fusion is cautious in the sense that if an agent’s belief is in conflict with those of higher priorities, then his belief is completely discarded from the merged result. We consider two strategies for the cautious merging of beliefs. In the first, called level cutting fusion, if inconsistency occurs at some level, then all beliefs at the lower levels are discarded simultaneously. In the second, called level skipping fusion, only the level at which the inconsistency occurs is skipped. We present the formal semantics and axiomatic systems for these two strategies and discuss some applications of the proposed logical systems. We also develop a tableau proof system for the logics and prove the complexity result for the satisfiability and validity problems of these logics.


An internal semantics for modal logic

Fagin, R. and Vardi, M. Y. 1985. An internal semantics for modal logic. In Proceedings of the Seventeenth Annual ACM Symposium on theory of Computing (Providence, Rhode Island, United States, May 06 – 08, 1985). STOC ’85. ACM, New York, NY, 305-315. DOI=


In Kripke semantics for modal logic, “possible worlds” and the possibility relation are both primitive notions. This has both technical and conceptual shortcomings. From a technical point of view, the mathematics associated with Kripke semantics is often quite complicated. From a conceptual point of view, it is not clear how to use Kripke structures to model knowledge and belief, where one wants a clearer understanding of the notions that are primitive in Kripke semantics. We introduce modal structures as models for modal logic. We use the idea of possible worlds, but by directly describing the “internal semantics” of each possible world. It is much easier to study the standard logical questions, such as completeness, decidability, and compactness, using modal structures. Furthermore, modal structures offer a much more intuitive approach to modelling knowledge and belief.

First-order classical modal logic: applications in logics of knowledge and probability

Arló-Costa, H. and Pacuit, E. 2005. First-order classical modal logic: applications in logics of knowledge and probability. In Proceedings of the 10th Conference on theoretical Aspects of Rationality and Knowledge (Singapore, June 10 – 12, 2005). R. van der Meyden, Ed. Theoretical Aspects Of Rationality And Knowledge. National University of Singapore, Singapore, 262-278.

The paper focuses on extending to the first order case the semantical program for modalities first introduced by Dana Scott and Richard Montague. We focus on the study of neighborhood frames with constant domains and we offer a series of new completeness results for salient classical systems of first order modal logic. Among other results we show that it is possible to prove strong completeness results for normal systems without the Barcan Formula (like FOL + K) in terms of neighborhood frames with constant domains. The first order models we present permit the study of many epistemic modalities recently proposed in computer science as well as the development of adequate models for monadic operators of high probability. We conclude by offering a general completeness result for the entire family of first order classical modal logics (encompassing both normal and non-normal systems).

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philosophy vs. information technology – printing requirements

I’m not a fan of discussing something in the context of that thing’s nature.  Thus I dislike saying things like: “well the nature of Wittgenstein’s philosophy is such that…”  Use of the expression imitates that conception of natural and/or logical necessity that Wittgenstein’s later developments (language games, the concept of grammar) nicely opposed, if not the necessity per se, its ill philosophical effects.

This is going to seem irrelevant but and it sort of is, but we could introduce another sort of language game where I’m apt to use or convey that sense of necessity I just got through justifying a disagreement with.  This has more practical relevance – printing requirements.  I figured my undergraduate stint with philosophy would, naturally, of necessity (yes I’m stretching it) – represent more in terms of printing costs vs. my graduate studies information technology.  After all, those old philosophy research papers from the 1940s, they’re available in PDF, but nobody would think (I hope not) to try to read them on a monitor where resolutions are roughly (something like) 40% that of the resolution of the real deal (i.e., reading a real book).  And since IT itself is a new discipline, it stands to reason that documentation ought to be primarily available on screen, right?

None of this turns out, with me, to be true.  I’m beginning to mooch off the network printers and/or printers of my family/peers.  So yeah, this is all leading up to my find for the week.  Practical knowledge is the new metaphysical necessity, it helps to not purchase your printing equipment at oversized vendors with terrible prices.  So yeah, this is definitely a practical post.

Printing needs

IT security surveys typically run anywhere from 20-50+ pages with lots of images and/or non-text/colored content.  Lexmark printers – especially the inkjets –  are pretty good for undergraduate/mid-level printing requirements.  I bought the Z1300 a year or so ago and while basic, its completely fine for low to mid-level use.  My gripe has to do with the software, and an aspect of it that’s quite irrelevant to its functionality.  There’s this annoying voice that activates whenever you use the thing, so I recommend NOT wearing headphones if you’re about to print something.  Of course you could shut it off in the options but who remembers that?  I’ll have to dig up an article on CNET which – I recall – named the z1300 a definite grab for the price.  If I buy online I tend to gravitate towards vendors who’ve been around for awhile and that sport high customer ratings.

Anyway, for printer toners and ink/other printer supplies its probably easiest to buy the stuff online. Make sure to review CNET or Tom’s Hardware Guide or something to make sure the stuff you purchase is legitimate and/or corresponds with your printer.  Might pay a few extra bucks for shipping but from what I can tell the price is initially reduced at the best online vendors.  If the vendor’s been around for several years chances are you should feel confident buying printing supplies from them.


Scanners probably aren’t too necessary for most undergraduates unless they’re into photo editing and/or really wanna share old pictures on social networking sites.  Color depth is important to watch out for, although honestly I dont’ know much about scanners other than a few good shopping places online.

Although, scanners would be extremely useful if you’re considering going into digital/online publishing for instance.  Especially if you were an editor or content producer for an academic publication, since physical documents are still digitally scanned as part of the update process for large academic databases such as EBSCO.

Old habits: maybe they don’t die hard

As an undergraduate, I certainly acted on that impulse to procrastinate. In my limited experience, philosophers or aspiring philosophers are not different in this regard, and in some ways, seem to procrastinate to an even greater degree.

Is this part of the philosopher in me slowly dying? If picture below is any indication, then either (p) I’m growing up or (q) I’m slowly divorcing myself from philosopher-type habits. As it turns out, if p or q, then r: D tracks his assignments.

the death of an old habit