Information Models

Art Griesser
Which conveys more 

information?

• Colorless green ideas sleep furiously

• “You don’t have no more troubles, Roscoe,” 

I tell him, “you and me is just become 

business partners.”
Colorless green ideas 

sleep furiously

• Grammatically correct

• Meaningless

Notorious example from Syntactic Structures by Noam Chomsky (1957)
“You don’t have no more troubles, 

Roscoe,” I tell him, “you and me is 

just become business partners.”

• Grammatically atrocious

• Meaningful

From the story “Hog-Belly Honey” in the anthology Nine Hundred Grandmothers by R. A. Lafferty (1970)
Grammatically Correct

Colorless green ideas sleep furiously

Noun Phrase

Sentence

Verb Phrase

Adjective Adjective Noun Verb Adverb

Noun Phrase
• Colorless ☞ nondescript

• Green ☞ immature or newly formed

• Sleep ☞ mental or verbal dormancy

Attempts at meaning

• “Newly formed bland ideas are inexpressible 

in an infuriating way”

• “Nondescript immature ideas have violent 

nightmares”

http://en.wikipedia.org/wiki/Colorless_green_ideas_sleep_furiously
Given only one, which 

is better to have?

• Grammar (syntax)

• Meaning (semantics)
Given only one, which 

is better to have?

• Grammar (syntax)

• Meaning (semantics)

XML

JSON

YAML
Given only one, which 

is better to have?

• Grammar (syntax)

• Meaning (semantics)

XML

JSON

YAML

UML

OWL

Express
Why XML Schema is 

Syntactic

Grammar 

specifies when a 

sequence of 

words 

forms a valid 

sentence

XML Schema 

specifies when a 

sequence of 

XML elements 

forms a valid 

document
Why UML is Semantic

• Describes relationships between 

information

• Does not define serialization

An companion to UML (XMI) does define serialization (of both 

models and instance data). XMI is not widely used for instance data.
Who cares, we’ve got 

them both, right?
Who cares, we’ve got 

them both, right?

Or do we...
Things Like This 

Happen

An XML schema whose purpose to convey 

to a bank everything necessary to record a 

collection of new mortgages, but had no 

connection between mortgage holder and 

property

(Details changed to protect the guilty)
Things Like This 

Happen

If a message is syntactically perfect...

does it have meaning if it omits vital 

information?
Can we have them 

both?

Yes...
Can we have them 

both?

Yes... if the semantics come first
Why do Semantics 

Need to Come First?
Bike Shed Effect

“Parkinson's Law of Triviality, also known as 

bikeshedding or the bicycle-shed example, is 

C. Northcote Parkinson's 1957 argument 

that organisations give disproportionate 

weight to trivial issues. Parkinson 

demonstrated this by contrasting the 

triviality of a bike shed to a nuclear reactor.”

http://en.wikipedia.org/wiki/Parkinson's_Law_of_Triviality
Wadler’s Law

“In the context of programming language

design, one encounters Wadler's law, named 

for computer scientist Philip Wadler. This 

principle asserts that the bulk of discussion 

on programming language design centers 

around syntax (which, for purposes of the 

argument is considered a solved problem), as 

opposed to semantics.”

http://en.wikipedia.org/wiki/Parkinson's_Law_of_Triviality
Why do Semantics 

Need to Come First?

• Because syntax soaks up resources

• Without addressing deeper problems

• Focus on the semantics delivers more value