Maybe. It's highly contested. One popular argument against that claim (which I agree sounds reasonable on its face) is that it turns out to allow us to draw some strong conclusions about the universe which, intuitively, should not be possible to conclude from our armchair (the "presumptuous philosopher").

In the philosophy literature, this often is framed in terms of a choice between the self-indication assumption or the self-sampling assumption.

https://en.wikipedia.org/wiki/Self-sampling_assumption

https://en.wikipedia.org/wiki/Self-indication_assumption

The canonical reference on this is Bostrom.

https://www.amazon.com/Anthropic-Bias-Observation-Selection-...

In the physics literature, this has been discussed as the assumption of "typicality".

http://journals.aps.org/prd/abstract/10.1103/PhysRevD.75.123... http://journals.aps.org/prd/abstract/10.1103/PhysRevD.81.123... http://arxiv.org/abs/0707.4169 http://journals.aps.org/prd/abstract/10.1103/PhysRevD.78.023...

Hartle and Srednicki's thought experiment involving the Jovians is a form of the presumptuous philosopher argument.

Only if they are indistinguishable from 'normal' brains.