"It would be preferable to find consciousness in the real world. Either reflected in behavior or in the physical structure of the brain."
"It would be preferable" expresses wishful thinking. The word refers to subjective experience, which is subjective by definition, while you are looking at objective things instead.
No, "it's preferable", same as "you should", is fine when there is a goal specified. e.g. "it's preferable to do X, if you want Y". Here, the goal is implicit - "not to have stupid beliefs". Hopefully that's a goal we all share.
By the way, "should" with implicit goals is quite common, you should be able to handle it. (Notice the second "should'. The implicit goal is now "to participate in normal human communication").
(This post grew out of an old conversation with Wei Dai.)
Imagine a person sitting in a room, communicating with the outside world through a terminal. Further imagine that the person knows some secret fact (e.g. that the Moon landings were a hoax), but is absolutely committed to never revealing their knowledge of it in any way.
Can you, by observing the input-output behavior of the system, distinguish it from a person who doesn't know the secret, or knows some other secret instead?
Clearly the only reasonable answer is "no, not in general".
Now imagine a person in the same situation, claiming to possess some mental skill that's hard for you to verify (e.g. visualizing four-dimensional objects in their mind's eye). Can you, by observing the input-output behavior, distinguish it from someone who is lying about having the skill, but has a good grasp of four-dimensional math otherwise?
Again, clearly, the only reasonable answer is "not in general".
Now imagine a sealed box that behaves exactly like a human, dutifully saying things like "I'm conscious", "I experience red" and so on. Moreover, you know from trustworthy sources that the box was built by scanning a human brain, and then optimizing the resulting program to use less CPU and memory (preserving the same input-output behavior). Would you be willing to trust that the box is in fact conscious, and has the same internal experiences as the human brain it was created from?
A philosopher believing in computationalism would emphatically say yes. But considering the examples above, I would say I'm not sure! Not at all!