I will explain you all went wrong.
You're right in the sense that we cannot be
certain of the origins of the apparent face.
But there are many precedents in nature of what appear to us to be face-like patterns/ structures, some have been seen on Mars (e.g. the Cydonia face and pyramids).
So many precedents that we have a word for those subjective perceptions- pareidolia.
There are absolutely zero precedents (and zero evidence) for
(1) Any form of manufactured extraterrestrial artefact
(2) Any form of intelligent life ever visiting Mars, excepting known human-built machines since 1976.
(3) Any form of alien life at all.
Do we know humans see faces where there has been no intent, or organisational ability, to depict a face? Yes, definitely.
Do we know that there are manufactured artefacts beyond Earth that we haven't put there since 1957? No.
Is there evidence that non-human intelligences exist, or have ever existed, anywhere? Not at present.
Is there evidence of a spacefaring human society before ours? No, and overwhelming evidence that the idea is absurd (although popular in science fiction).
Nonetheless we cannot definitively falsify the hypothesis that this "face" has been intentionally made at present.
But when formulating our descriptions and understanding of the universe, it is often sensible to provisionally accept what seems most likely based on the evidence we have, and by looking for analogous precedents.
I'm not sure the analogy with Schrödinger's cat is that helpful; (without wanting to take us off-topic) some physicists who think it's a useful description of macro-scale effects dependent on quantum events would state that the cat's status is
intrinsically unknowable, and thus exists in a superposition of states, unless you make an observation.
IIRC Schrödinger devised this thought experiment in an attempt to demonstrate the intuitive implausibility of such an interpretation.
The rocks that make up the face exist. The face is either a case of pareidolia (likely) or has been deliberately designed (very unlikely, as far as we currently know).
It is not in a superposition of states just because we don't know for certain at present.
Not being able to conclusively demonstrate that it results from pareidolia does not make an intelligent origin more likely.
The status of the half-face on Mars is not intrinsically unknowable. It is possible some future orbiter or rover will image it from other angles and/ or lighting conditions and demonstrate that the apparent face is a product of pareidolia.
If not, perhaps in the future it will be visited by astronauts or robots who could look for evidence of carving or machining, and who could test if it was minerally distinct from its surroundings.
However, sending a multi-hundred-million dollar probe specifically to investigate what is
probably an example of pareidolia might be questioned at the present time.
(Edited to add: If I was Earth Finance Minister I'd take the money from Mr Putin's "defence" budget and start building the probe tomorrow, but unaccountably I haven't been elected to that position yet.)
