☛ XKCD: “Extended Mind” by Randall Munroe, no. 903, May 25th, 2011

On XKCD’s website (not here), if you place the cursor of your mouse over the illustration, you’ll get this afterthought:

Wikipedia trivia: if you take any article, click on the first link in the article text not in parentheses or italics, and then repeat, you will eventually end up at “Philosophy”.

From the article “Spark Plug”, it takes 17 clicks to get to “Philosophy” (through “Cylindar head”, “Internal combustion engine”, “Engine”, “Machine”, “Energy”, “Physics”, “Natural science”, “Science”, “Knowledge”, “Fact”, “Information”, “Sequence”, “Mathematics”, “Quantity”, “Property (philosophy)”, and “Modern philosophy”).
From the “Xkcd” article… it takes 19 clicks (9 clicks to get to “Natural science” and then it follows the same path as “Smart plug” does, all the way to “Philosophy”).
[UPDATE – May 8, 2012] A few days after Randall Munroe posted the above XKCD panel, someone actually build a web interface to test and visualize this phenomenon. See Xefer: “All Roads Lead to “Philosophy”” by Jeffrey Winter, May 31, 2011. Test it here.