You are right that my pithy summary was misleading. This may be a terminological point, but I am confused about how a hard-core scientific anti-realist can believe in predictions. At the very least, someone who thinks there is no objective physical reality has a hard time explaining why science seems like a one-way ratchet, with predictions always getting better and never getting worse.

I agree that science, like all facts, are socially-mediated. I think the case for incommensurability between certain scientific theories is overwhelming. But it seems like there must be some regularity external to human minds for scientific predictions to work the way we've observed them to work. (I vaguely recall my Philosophy of Science professor saying something like "Preserve the phenomena")

In short, the problem of Induction says that we can't prove the sun will rise tomorrow in the sense that we can prove that 3 + 5 = 8. But hardcore scientific anti-realism proponents seem like they should be surprised when the sun rises tomorrow (more precisely, when they experience what appears to be the sun rising tomorrow) because they literally believe that there is no mechanism that suggests it will happen. (Or am I just setting up a strawman?)