In most anthropic discussions, “I am a typical observer” or “I shall regard myself as a typical observer” is taken as a given truth. However, I think that very idea is misguided. Because “observer” is a target drawn around where the arrow is. The arrow is the first person “I” in this analogy.
Everyone knows who the first-person “I” refers to since the only subjective experience felt is due to that particular physical body. We then put physical systems similar to this body into a category, and give it a name. But what similar feature is chosen to perform this grouping is arbitrary. From my personal perspective, such groups can be middle-aged men, things that can do simple arithmetic, synapsids, carbon-based lifeforms, macroscopic physical system, etc. It would be rather absurd to think “I” am typical for all these groups.
Furthermore, what does “typical” among a group really mean? If we look at the features that define a category, then of course I am similar to everything else. Since this grouping is based on everyone having that feature in the first place. This gives a false sense of mediocracy. But why would I be typical in terms of other features? e.g. for macroscopic physical systems, the defining feature is its scale, why should I expect myself exist at a typical time for this group? There is no reason for it. Various anthropic camps try to support this by regarding “I” as a random sample from the group. But that is just an ad-hoc assumption. And that is the root cause of various paradoxes.
It is not a coincidence that most anthropic theories have trouble defining what “observer” really means, which in turn messes up the reference class. (This is not exclusive to SSA. SIA and FNC are plagued by it too). Because it has no hard definition. It is just a circle drawn around the first-person “I” with a radius of anyone’s choosing.
Many think “observer” can be conclusively defined as someone/something that is conscious. But what is consciousness in the first place? The only consciousness that anyone has access to is that of the first person. “I know I am conscious, and can never be sure if you are just auto-piloting philosophical zombies.” I guess other people/animals/programs might also be conscious only because of their similarity to myself.
All in all, I feel people who hold “I am a typical observer” as an indisputable truth didn’t take a hard look at the meaning of “I” or “observer” or “typical”.