Editing 1417: Seven

The number seven being the number for when sets become indistinguishable is possibly a reference to {{w|The Magical Number Seven, Plus or Minus Two|Miller's law}}.  Especially considering that this is a law dealing with human memory, which Cueball is having issues with.  However, this law refers to elements ''within the same set'' becoming indistinguishable, rather than the indistinguishability of different sets of the same size - indeed, its original tests involved either distinguishing between the items, or repeating them back ''in the correct order''.  But then again, that might be part of the humor.

For each of the seven lists below, the relevant item's traditional position within its own list of seven, according to Wikipedia, is '''not''' necessarily equal to its position on the list in the comic. For some lists the position is equal, but not for all. For instance Sneezy is traditionally never mentioned first amongst the dwarfs since the leader Doc normally comes first. But "phylum" is the second major taxonomic rank as is "phylum" the second item on the list in the comic.

!{{W|Seven Dwarfs#Disney Dwarfs|Disney's Dwarfs}} from ''{{w|Snow White and the Seven Dwarfs (1937 film)|Snow White and the Seven Dwarfs}}''<ref group=c>The order is taken from the page about the movie, but Sneezy is never no. 1. On the other page, which is listed alphabetically, he is no. 5.</ref>

!Major {{w|taxonomic ranks}}.<ref group=c>There are technically 8 on this list as {{w|Domain (biology)|domain}} has been included as the first in the list in 1990. It is, however, still normal to only list the 7 ranks in the table.</ref>

!{{w|Continents}}<ref group=c>Continents do not have a fixed order and can be ordered by several criteria. This table orders the continents by population, by which Europe is the third-largest and matches the position in Cueball's list.</ref>

The title text extends this saying he also does the same with the set of the seven days of the week. There are several sets of 7 featuring the name '''Electra''', which are all listed in the table below. Until [[Randall]] tells us which he meant, all are possible.

!{{w|Pleiades (Greek mythology)|Pleiades}}, Seven Sisters, nymphs and daughters of Atlas and Pleone in Greek mythology<ref group=t>List as on Wikipedia, with the oldest first and the youngest last (it's unclear whether the ones in the middle are also listed by age). In any case, only in reverse alphabetical order Electra would be no. 5: Taygete, Sterope, Merope, Maia, '''Electra''', Celaeno, and Alcyone.</ref><ref group=t>Electra is one of the septet of Pleiades sisters, one of the named stars in the Pleiades Star Cluster, and also of the septet of the complete extant plays by Sophocles.</ref>

!{{w|Pleiades|Pleiades}} Star Cluster <ref group=t>[[Randall]] names the Pleiades his favorite astronomical entity in the {{xkcd|about|"about" section}} on his website.</ref><ref group=t>In the order of stars named for the Seven Sisters starting from 12 o'clock position and counting clockwise.  This list does not include Atlas and Pleione, parents of the Seven Sisters, and the remaining two named stars in the Cluster, which would be the eighth and ninth stars, respectively.</ref>

*Concerning the seven colors of the spectrum (no. 4 on the title text list) {{w|Indigo#Classification as a spectral color|indigo is stuck in}} by {{w|Isaac Newton}} to add up to the seven notes in the {{w|Scale (music)#Western music|Western musical scale}}.

**It should be noted that {{w|Indigo#Classification as a spectral color|Newton probably meant}} the colors {{w|cyan}} and {{w|blue}} as we think of it today, rather than blue and {{w|indigo}}.

**Also note that in a {{w|rainbow}} you usually {{w|Rainbow#Number of colours in spectrum or rainbow|cannot distinguish more than six colors}} with cyan melting in with green and blue and the same for indigo with blue and violet.

**These are also the traditional seven artists' pigments, {{w|Roy G. Biv|with the accompanying mnemonic "Roy G. Biv"}} (or the "Richard Of York..." counterpart mnemonic, for those indoctrinated by a different method). Indigo dye is a widely known and readily available coloring agent. The ongoing ubiquity of the ''pigment'' (think denim) gives it a unique prominence despite its uncertain status as a spectral color.