Well first of all I think sapience has nothing to do with the state of being alive. Second of all, nowhere in the Homunculus rules does it say it's either alive or that it has has an aura which then implies it is alive. OTOH pg 312, Auras and Astral Forms, establishes a trinary status for all things. They are either:
Well you're very mistaken. As Spience says they are as smart as people see definition below. A Homunculus, has skills can aparently learn new ones (See below), has critter powers, can think and moved around by itself, and it can be killed, all of which clearly implies its alive. Can you think something not alive that can choose to learn new skill that not alive? Nothing in the rules says characters are alive at generation ether, it obvious.
Sapience
Type: P Action: Auto
Range: Self Duration: Always
Sapient critters are self-aware, capable of making
their own choices, and are generally at or above the level
of Homo sapiens. While most critters are considered Unaware (see p. 131) of any skill they don’t possess, sapient
critters are merely Untrained (see p. 131) and can default
normally.
They are also capable of learning new skills if
they so choose.Most sapient critters are mundane, but they are capable of Awakening and possessing a Magic attribute.
Awakened sapient critters are capable of learning any
magical task they set their minds to, and follow the same
rules for magic as normal characters. While no sapient
critters are known to have Emerged as technomancers,
the appearance of “technocritters” has led many scientists to believe that it’s only a matter of time—if it hasn’t
already happened.
Living, and in possession of an aura.
Magical but not living, and in possession of an astral form.
None of the above, and having neither.
None of that is in the rules, you may like imagine it is but ain't so. Watcher have ability choose to manifest (See below). So how to your mind is something not alive able to CHOOSE to manifest.
Astral Form
Type: M Action: Auto
Range: Self Duration: Always
A critter with this power only exists in the astral plane.
Only astral attacks or mana spells/powers may hurt an
astral critter; physical attacks or spells/powers have no
effect. The reverse is also true; an astral critter can only
affect dual-natured beings or those on the astral plane,
whether through astral projection or astral perception.
Critters with this power may manifest on the physical
plane in the same way as astrally projecting magicians
(see p. 313). There is absolutely no correlation between having Sapience and being alive.
You meet a lot of things that have free will, choice and learn things aren't alive? This isn't a statistic model SSDR. We aren't analyzing probabilities here. We aren't searching for causality. Dead things don't do any of those things.
As of 5th edition (maybe 4th, didn't play that one so much), watchers are no longer spirits. I don't think they have a categorical name for what they are. From the first sentence on Watchers, pg 298:
Just to wrap this up once for all. Lets go look at what you referenced:
Watchers are like spirits, but in actuality are entities
bornfrom the ritual leader’s own mind rather than the metaplanes. Page 298 First sentence under Watcher (Minion.)
So the rule say they are born.
born
/bôrn/
1.
past participle of bear1 (sense 4).
adjective
1.
existing as a result of
birth.
birth
/bərTH/
noun
noun: birth; plural noun: births
the emergence of a baby or other young from the body of its mother;
the start of life as a physically separate being.
QED the rule do say they are Alive, and that is RAW. So SSDR your whole argument is in fact founded on false assumption. I'd suggest reading more closely in the future. Good Night.