[dragonwriter]

> The tricky bit about consciousness is that nobody can find a useful way to measure or define it

This, particularly the “define” part, is the key problem.

> Now imagine we magically imbue that deer with a consciousness in this situation. What measurably changes about their behavior? They still scream, try to run, struggle to survive — I can’t think of any way the situation would be different.

Of course you can't, because you haven't defined what consciousness means. Without a definition, you can't answer the question of “what is different if it is present vs. absent”.

> Thus, the claim “deers have consciousness” is non-falsifiable

It's beyond that, it's meaningless.