"Despite their appealing simplicity, syllogisms don't work well in the real world, because most of the data we use is not amenable to such effortless recombination. As a result, the Semantic Web will not be very useful either...This sentiment is attractive precisely because it describes a world simpler than our own. In the real world, we are usually operating with partial, inconclusive or context-sensitive information."
Hmm, relational databases are used everyday and they make assertions - even incorrect ones. When you create a row in a table you're saying "Andrew lives at 12 Mulberry Lane" or "Andrew has $123 dollars in his account". Relational databases have the same problems with respect to partial, inconclusive or context-sensitive information.
RDF by itself, has no enforced schema, so you could quite easily store data that you would not be able to put in a relational database. However, by adding schemas you can then start querying or preventing from being stored data that does not fit your schema. It's a lot more flexible in that manner.
"Each of those statements is true, in other words, but each is true in a different way. It is tempting to note that the second statement is a generalization that can only be understood in context, but that way madness lies. Any requirement that a given statement be cross-checked against a library of context-giving statements, which would have still further context, would doom the system to death by scale."
To quote Tim Berners-Lee in "Weaving the Web":
"Databases are continually produced by different groups and companies, without knowledge of each other. Rarely does anyone stop the process to try to define globally consistent terms for each of the columns in the database tables...If HTML and the Web made all online documents look like one huge book, RDF, schema and inference languages will make all the data in the world look like one huge database"
"If a reasoning engine had pulled in all the data and figured the taxes, I could have asked it why it did what it did, and corrected the source of the problem.
Being able to ask 'Why?' is important. It allows the user to trace back to the assumptions that were made, and the rules and data used. Reasoning eninges will allow us to manipulate, figure, find and provide logical and numeric things over a wide-open field of applications."
"Is your "Person Name = John Smith" the same person as my "Name = John Q. Smith"? Who knows? Not the Semantic Web. The processor could "think" about this til the silicon smokes without arriving at an answer."
Defining equality is exactly what Semantic Web technology allows you to do - by using things like OWL. You can say "Person Name = Name" if Person Name's First Name is equal to Name's Christian Name and Person Name's Last Name is equal to Name's Surname. In fact, defining equality also includes different languages and differing literals (like II, 10, 2, "two", etc.).
Again, we get Cory with the Metacrap and Mark with his tag soup.
Reading the sections "Worldviews Differ For Good Reasons" and "Worse is Better" sounds very similar to the sections in "Weaving the Web" about the Semantic Web and using databases, except of course Berners-Lee says the Semantic Web takes these things into consideration.
Clearly, Clay has missed the point of RDF and Semantic Web technologies. Maybe people should stop concentrating so much on the "Semantic" part of the name and more on the "Web" part. Saying that you can't use the Semantic Web technologies "a bit at a time, out of self-interest and without regard for global ontology" is a lot like saying you can't use TCP/IP, HTML, or HTTP for the same reasons.
Most of these arguments are just common Semantic Web misunderstandings. Maybe the Tuple or Relational Web would've been a better name.
The Semantic Web, Syllogism, and Worldview