The consensus at the time of Copernicus was that the Sun revolved around the Earth, so I'm not too worried.
Ah, playing a variation of the Galileo Gambit, I see. One could utter this statement of yours after they are challenged on any claim at all... and it does nothing to the truth or otherwise of what they claim. It simply makes them look like an arrogant fool. And, channelling my inner Sagan for a moment, bear in mind that while people may have laughed at the idea of the earth revolving around the sun, people also laughed at Bozo the clown.
And there is actually more people who think the argument is valid than people who think it is invalid, even without counting myself.
Further, I can justify to myself, in a rational way, why the argument is valid, so I can live with your "consensus", for what it's worth.
An appeal to consensus from a group that clearly has no particular skill in modal logic? Yeah, that'll get you far.
Why not go the easier route, post a syllogism that uses classic logic, and then debate the truth or otherwise of the far stronger premises. It amounts to the same thing. Or is your desire to use premises that can be more easily accepted as true your overriding concern, even if it limits the strength of your conclusion?
I don't know yet if I'll post the explanation. Right now, I don't feel like it.
So you really have nothing to offer here. You post a question and are unwilling to discuss it in a manner conducive to actual discussion. You throw your toys out of the pram when you don't like what people say. So why are you here? To poll a group of people not particularly versed in modal logic whether their "expert" opinion is that your argument is valid or not?
None of you can prove his assertion that the argument would be invalid.
So you're working on "its valid until someone can prove it isn't"? What is the ultimate purpose of your argument? Why not post a form that is far easier to determine its validity (I.e. using classic logic) and then debate the truth or otherwise of the stronger premise? At the moment, as surmised by JamesR, and explained in more detail by Baldeee, your argument may be valid but the conclusion is incredibly weak. And of no more overall worth as an argument than a classic argument would be, once full discussion of the premises has been undertaken.
Is your intention to try to argue that consciousness determines what we do? If so, crouching an argument in modal terms is not going to get you there any quicker, and in fact more slowly, than a classic approach, as you'll waste time over assessing whether the argument is valid. And then to be meaningful you still have to go through establishing how things actually work in our world, rather than work with simple notions of what is possible in at least one conceivable world.
All anyone does here is merely assert it is invalid, when they do. People who have claimed invalidity on ground of undistributed middle did so on the basis of a different argument, which is clearly something absurd to do.
If you can't work out how dissection of a frog doesn't help you understand the frog, maybe you're in the wrong field of study. Furthermore, if you can't provide argument as to why you think your own argument is valid, why should others post any explanation as to why they think it invalid? As it is, those people, myself included, have posted far more about why they think it invalid than you have posted as to why you think it valid.
So stop being a hypocrite, stop being arrogant, stop being a troll. Can you do those things for us, please?
And I'm not interested in convincing you it is valid. I'm only interested whether you think it is valid or not and in proofs you can offer that it is not valid.
"You can't prove me wrong therefore it's right!"
Given your modal approach to the issue, one has to question why you have gone down this route if you are at all interested in anything other than modal logic itself. And if not, why you would bother seeking responses from a group who clearly aren't able to help you. The one person who has offered anything formally is one who says they don't know if it is valid or not. But you seem to be happy taking the consensus of everyone else, who have, it seems, even less grounding in modal logic.
If you're here to ultimately discuss the subject matter of your argument, there are far easier ways. One can construct a fairly simple syllogism and then discuss the truth or otherwise of the premises. That is far easier than creating a modal argument, arguing over its validity across 3 or 4 threads, only to then have to discuss the same issues of how things actually work.
If, however, you're here to discuss modal logic, and formal structures and proofs thereof, then you're clearly not going to get that here. So why persist?