[Michiel]

> However I don't know if that reflects some deeper truth about the world, or just my bias in how I answer the questions.

It's the same reason why you always end up on "Philosophy" if you're browsing Wikipedia and consistently follow the first link in each article. Here's the path for "Airplane":

  Airplane
  Fixed wing aircraft
  Aircraft
  Vehicle
  Motion (physics)
  Natural science
  Science
  Knowledge /* we know where this going... */
  Fact
  Proof (truth)
  Argument
  Philosophy

Try it yourself: http://www.xefer.com/wikipedia

[Kronopath]

I think that website cheats a little bit. The first link in "Science" is not "Knowledge" but "Latin", where it's describing the root of the word "Science". If you follow it properly, you'll find that even the article for "5 Whys" doesn't go to Philosophy:

  5 Whys
  Technique
  Technology
  Tool
  Goal
  Animal
  Eukaryote
  Organism
  Biology
  Natural Science
  Science
  Latin
  Italic Languages
  Indo-European Languages
  Language Family
  Language
  Human
  Taxonomy
  Ancient Greek
  Greek Language
  Indo-European Languages // Infinite loop!

[Michiel]

That path seems to go in the same direction, but then it diverges in Science, mostly due to the first sentence on that page, where [Latin] and [knowledge] are links:

> Science (from [Latin] scientia, meaning "knowledge") is a systematic enterprise that builds and organizes [knowledge]...

It happens again in Taxonomy, which otherwise would surely lead to Philosophy from the [classification] link:

> Taxonomy (from [Greek]: τάξις taxis "arrangement" and Greek: νομία nomia "method"[1]) is the science of identifying and naming species, and arranging them into a [classification].

On our way to Philosophy we are constantly confronted with Latin and Greek concepts, because Rome and Greece are where many of the concepts in Philosophy originated.

[esrauch]

I think the wikipedia game specifically excludes words in parenthesis and italics. Following those rules you actually do get to Philosophy, and you also get to Philosophy from Indo-European Languages.

Though there are some other cycles that exist.

[sev]

I had heard this before and just tried it...awesome!

It's also interesting that philosophy links to existence (ontology) and that links back to philosophy.