You, you are going to be crucified by scientists. :-) More seriously, I get your point but many discoveries are done by finally observing something which exist

You, you are going to be crucified by scientists. :-) More seriously, I get your point but many discoveries are done by finally observing something which existence has been anticipated, hypothesized but still unproven. A planet that had an effect on nearby objects because of its gravity for instance. Or the Higgs boson. So, yes, thinking of things that are not proven to exist (yet) is often scientifically helpful. You still want to apply Occam's razor of course.