It happens. Guess you can't be an objectivist, then. You'll get over it ;)
In any universe in which the law of cause and effect exists, as it does in this one...
I suppose it would be crass of me to point out that this assertion is also far from proven true, but you can see David Hume's ideas on causation if you like....
"Beneficial" effects are a "good" choice, "detrimental" effects are a "bad" choice.
This is knowable, and provable -- assuming cause and effect.
Well, you're really assuming quite bit more than causality, but you're right - that's a necessary assumption. Which, again, just goes to show that you're not really an objectivist if you're going to assume things like causality, but you knew that. If it's objectively knowable that causality exists, which objectivism says it is, then you shouldn't simply accept it on faith until it's been rationally proven, again according to objectivism. Dunno how you're supposed to actually get anything done that way, but it is what it is - you're definitely right about that...
We take cause and effect as an objective reality as true based on observed evidence, as I know you know.
But yes, this all could be a dream . . . like Bobby dying on Dallas.
Do you find that "deep"? I don't.
Other than this, "we can't know anything for certain because it could all be a dream", do you have any actual substance to discuss?