I agree with John that most astronomical press releases present far more certitude than is warranted. Would you feel better if it read: "Astronomers theorize that quasars consist of supermassive black holes, each surrounded by a vortex of gas."? What level of proof is needed before a statement can be made without such a preface?

How do you feel about the certitude of the following statements? How many need a "astronomers theorize that..."?

- there's a supermassive black hole at the center of the Milky Way.
- the moon orbits the earth.
- the Andromeda nebula is a galaxy, not unlike the Milky Way, that is 2 million light years away.
- type Ia supernova are caused by white dwarfs accreting matter beyond the Chandrasekhar mass limit.
- the age of the universe is 13.7 +/- 0.2 billion years old.
- in the ultraviolet, dust is highly forward scattering.

Certainly more than one side should be viewed on the question of quasars. But at what point does one side become the dominant paradigm? At what point should it? At what point do Arp's ideas become a historical curiosity? Is it possible that the rest of the astronomical community has gotten it wrong and Arp has it right? I guess that is possible. I don't think, though, that most astronomers think conspiratorially about their theories. Egos do get involved sometimes, of course. And that applies equally to Arp, too.