You are assuming that objective reality exists

It must exist, or our minds would be able to directly influence 'reallity'.

If lots of people think Logicaly the world will progress Logicaly...

You're assuming that if reality is subjective that there even ARE other people.

...by meditation or intake of halucinogenic substances...

Now these substances would be a part of objective reality. If not, then it's only your mind... See my point?

There is no way you could prove this to be untrue, just as it can't be proved to be true either from one person to the next. Essentialy Logic is your own construct in this scenario.

It can be proved untrue, by showing it's logically inconsistent. I disagree that logic is each person's own construct. Logic is completely self consistent. Must be. If anyone had 'different logic' it would be faulty logic.

might be an abstract fleeting 'phase' in an infinity of different world systems with an infinity of operative conciousnesses yet all corroborating to a single conciousness.

Infinity is paradoxical, and therefor does not exist in reality. Incomprehensibly huge numbers exist, yes, but not infinity. Infinity is more of a process (it's not a number), and is therefore limited by time.

Could it be that the researcher 'wills' the results of an experiment?

Only if reality was subjective as opposed to objective, but it has been shown that it is not.

And for the record, I don't assume this scenario to be true, I am partialy daydreaming and trying to prove that you can't fully assume with perfect truthfullness that the world is Logical and Objective.

You cannot prove something without logic, and since you're attempting to disprove logic, there is no way you can prove your statement!

That which cannot be false.

I don't think I agree with that. Can't think of an example offhand, but I'm sure something can be defined such that it cannot be false, yet is not true...

can you provide and example of a "proof related to subjective reality?".

That's a hairy subject, lol

I was thinking any logical proof could be considered subjective if all knowledge is tentative, which I agree with only to a certain extent. But I believe logical proofs have bearing on objective reality (as do most people). When you think about it, nothing really matters if reality is only subjective.