Do cantrips count as zero level spells?

Question

In pathfinder magic an arcane spellcaster can memorize a lower level spell into a higher level spell slot if they wish.

Eg use a 3rd level spell slot to memorise a 2nd level spell.

Does this include cantrips?

Arcane Spells Wizards, sorcerers, and bards cast arcane spells. Compared to divine spells, arcane spells are more likely to produce dramatic results.

Spell Slots: The various character class tables show how many spells of each level a character can cast per day. These openings for daily spells are called spell slots. A spellcaster always has the option to fill a higher-level spell slot with a lower-level spell. A spellcaster who lacks a high enough ability score to cast spells that would otherwise be his due still gets the slots but must fill them with spells of lower levels.

Answer 1

There's nothing prohibiting you from preparing a 0-level spell (cantrip) in a higher level slot [1]. The rules state the spells are "cast like any other spell", with the notable exception that "...they are not expended when cast and may be used again" [2]. Per the RAW, this would equally apply even if it was prepared in a higher level slot. Cantrips don't have any restrictions otherwise (and the only distinction from non-cantrip spells is, in fact, a benefit).

The question I have though, and this is admittedly just out of curiosity, but why would you want to waste a valuable higher level slot on something as mundane as a cantrip?

SOURCE

[1] http://paizo.com/prd/magic.html ("Preparing Wizard Spells")

A spellcaster always has the option to fill a higher-level spell slot with a lower-level spell.

[2] http://www.d20pfsrd.com/classes/core-classes/wizard#TOC-Cantrips

Wizards can prepare a number of cantrips, or 0-level spells, each day, as noted on Table: Wizard under “Spells per Day.” These spells are cast like any other spell, but they are not expended when cast and may be used again. A wizard can prepare a cantrip from an opposition school, but it uses up two of his available slots (see below).

Answer 2

Cantrips are definitely 0-level spells, and that should mean you can memorise them in a higher -level slot. However, the real question from there is - are they used when cast, if memorised in a higher level slot?

The definition of cantrips comes from the Cantrip Class Abillity, as shown below

Cantrips: Wizards can prepare a number of cantrips, or 0-level spells, each day, as noted on Table: Wizard under “Spells per Day.” These spells are cast like any other spell, but they are not expended when cast and may be used again. A wizard can prepare a cantrip from a prohibited school, but it uses up two of his available slots (see below).

This doesn't really clarify one way or the other, but it certainly seems to indicate that it's the level of the spell that defines a cantrip, which leads me to believe you could still recast a cantrip memorised in a higher-level slot.