I foreign matter disappears when you go through, and bacteria and viruses are foreign matter, it would be great to set it up as a very cheap medical center. Ditto for removing shrapnel and the stuff that causes lung cancer.
Too bad that cancer cells themselves would presumably be recognized as “naked human”. If they weren’t your medical center would be very very profitable.
@XT
Well, first of all, I’d hire awesome agricultural dudes. “How I got started” would be muchly in their hands. But if I was in charge, I would take whatever corn like plant (or wheat, potato) is available in the area, take as much seed as possible and plant it in a number of well separated plots. I would cull anything weak looking quickly in most of them and leave a couple of plots to go wild for a season and see if anything interesting happens late in development there. Whichever plot/plant seemed to go in the right direction, those guys get an extra plot next season.
Look at how marijuana has increased in potency in the last few decades. They weren’t using high tech dna analysis. They just “get” how crossbreeding works.
Maybe the farm research happens in greenhouses? Easier to till, more controllable growing season, definitely a lot more control over what is pollenating what. The hypothetical posits essentially an earth clone, as opposed to an earthlike planet. Surely the appropriate sands for suitable glass would be in the right place, just need someone to go fetch it (a potentially daunting task). Or maybe someone around here knows how to make plexiglass from nettle leaves and squirrel oil? I dunno. Maybe it WOULD be harder than folks think to get to the next step, even if knowing what that next step is cuts out 1500 years of trial & error & waiting around for dumb luck to happen.
If only there were some kind of crowdsourced thinktank where all the minds in the world could be brought together virtually. Someone could ask, “Hey, how do you…” and someone else could respond with, “Oh, I know all about that. Here’s what you do…” I’ll bet that would be an effective tool in deciding what needs to happen in order to put together a bootstrapping plan for a previously human-free world. Such a thinktank would need to clearly express its goals, including a metric for how long it has been working toward them. I’d be willing to bet it would be frequented by some of the hippest people in the world, possibly a few total dipsticks.
Well, marijuana farmers and cultivators are able to use tools and techniques from this world, including fertilizers and irrigation. 
Sure, you’d hire agriculture dudes. So would I. And send them through…naked. With no tools, no technology and not even maps or climate models of where the portal is, unless you were planning to spend a few decades first scouting things out. Then…what? They wander around until the see something they recognize and hope it’s something usable? They are only going to be able to wander a few hours from the portal, and they will be at risk doing so. Or, if you spent the time to build the infrastructure, they could sit in the fort you had constructed while scouts brought them back stuff to look at. But we are talking about what’s in walking distance of the portal. Is this portal in pre-Europe? Is it on the pre-Russian steppes? Is it in the pre-Austrian Alps? Is it in pre-Africa? We wouldn’t even know that very quickly, and this assumes this new Earth is an exact analogue of our Earth. But what era is it? Is there a nasty ice age about to descend on the whole thing or a run away greenhouse effect? If we are talking pre-human times both of those possibilities happened relatively frequently after all. Today, right now and for the last 10k years we are living in an unusually stable climate…but going back to some random time in the past of this planet would be a crap shoot. I mean, the weather could be fine today, but what about next year? In 10 years where your portal is at could be an inland ocean or under a mile of ice.
I concede that being able to bolt back home and be able to eat and get medical treatment is going to be a huge advantage, but it will take even the smartest and most skilled people a hell of a long time to build anything meaningful, and it will take even today’s top genetics folks and your agriculture dudes longer than their lifetimes to bootstrap the genetic change from grass to corn, even assuming some lucky breaks.
To expand on my last: we now know about the difference between dominant and recessive genes. We would much more quickly recognize when inbreeding is good and when to bring in some new breeding stock. We may not do it perfect but the idea that we’d be at the same level as a paleolithic farmer is beyond ridiculous.
Eta: and we have a shitload more knowledge about what good fertilizer and irrigation is. How can you ignore that, XT?
You are right, because they would be better off, already having a basic infrastructure and culture as well as knowledge of their world that we would have to build from scratch. Also, I don’t think the native Americans who cultivated corn in the paleolithic. Didn’t that end something like 11k BCE?
What about using paragliders for scouting & gathering? I’ve seen those guys take off from level ground when the wind is good. Just need a suitable material to make the glider & tackle with. Wonder if any old moth cocoons would work or if you’d need actual silk worms. Maybe spider silk, but I won’t be helping on that project.
Well, I don’t think anyone would even attempt to make food for a seriously long period of time. Probably years or decades before it’s more efficient to head back to Earth 1 for food than it is to grow food and live full time in earth 2. Maybe orchards would be worthwhile as it would allow extended shifts.
I think within a year or two you have a steam or water wheel powered machine shop(s).
Where are you getting the metal from? How are you forging it? Is there a stream near your portal and materials to build a water wheel to build your powered machine shop? 
Seriously, listening to this is like that guy on Galaxy Quest telling the captain to look around and if he can build a rudimentary lathe…
I don’t know, man. You seem to be saying that the last few thouand years of knowledge is meaningless if you don’t have a screwdriver. I’m pretty sure I could cobble together a group of Mennonites to build me a water wheel in a few years.
No, not at all. Once you actually build the infrastructure to support the sorts of studies and experimentation you guys are talking about you’d be able to fast track quite a bit. But what you and most others are discounting is that those ‘paleolithic farmers’ knew their world a hell of a lot better than you will know this new one. Hell, what if what you need to make that corn is 250 miles away? How long will it take you to find it? What if the copper Snarky needs is 25 miles to the south west and 5 meters down…how long will that take to find and exploit? What if the bamboo Inigo needs to make his gliders is over in pre-China…5000 miles away. As are the silk worms.
The thing is, those Mennonites had some serious advantages over you on this new world…they actually had technology and a pipeline infrastructure to make more, materials and knowledge of their world. Think about this…the folks who tried to build a colony at Roanoke were centuries ahead, technologically, to many of the native tribes…even more to the tribes who first came over to the new world across the Bering Straights land bridge. Yet they died out pretty quickly because they didn’t know jack shit about the area they were in, what resources they could actually use, or even how to best exploit the native resources. And THEY are going to be way ahead of you, since they aren’t naked with zero technology and zero resources and starting from total scratch without even the contents of your stomach or your filings.
I think you equating ancient nomadic people crossing the Bering strait to modern people crossing a magical bridge to EarthII (where we get to choose the crossover point) is pretty stupid.
Yeah, but they didn’t have the ability to teleport back to the 21st century whenever they wanted.
And it would be, if that’s what I did. Sadly, you didn’t even grasp the argument I was making, as evident by this post, and since you can’t be bothered to keep things civil or even make a descent response I don’t see the point in continuing on this discussion.
And I’ve admitted that’s a huge advantage, logistically. But how does that help you in building the infrastructure to explore or to test or experiment? How does it tell you what is 10 miles away, or 50, or a 1000? As you can’t take any of the tech from here back with you, or bring any of the data back from there to analyze using modern technology, all you’ll really have is what you can memorize and bring with you to transcribe here, and then memorize and transcribe back there…once you build the infrastructure to even be able to have writing materials to write on and some place to store it that won’t be lost or destroyed by accident or even intentionally.
It is pretty much what you did. If you want to get all offended, that’s your problem.
I’m not offended, merely baffled that you don’t get it. I wasn’t equating native Americans coming across the Bering Straights with our theoretical naked Earthlings. I was saying that even though the Roanoke colonists were vastly technologically superior they couldn’t make it in the new world while 10,000 years before those native Americans were able to survive. The point wasn’t to equate, but to illustrate that one of the main issues is that these folks from Earth aren’t going to know anything about the environment they are in. What’s the climate like in the winter? In the Summer? What animals and resources are there? What animals and resources are 10 miles away? 100? 1000? It will take decades before they can even build up the rudimentary data they need because they will have to build literally from scratch. Yeah, it’s nice they can pop back through the portal, but consider…how’s that going to work out for a scouting force that’s even 10 miles away? Not going to really matter that there is a magic portal 10 miles away if they can’t get back to it. To build up to even explore that far is going to take a lot of time and effort.
Now, going back to the corn thing, consider…how do you FIND the stuff you want to try and use to start your generational genetic experimentation? If it’s 100 miles away it might take you decades before you stumble on it…or centuries. Certainly, by then you will have agriculture up and running, perhaps you will have found metal or other resources you can use as well. Then you would have to plant the stuff and select for the traits you want, then cross breed those and plant and select. What’s the growing season where you are at? How many crops a year can you get? 2? 3? Maybe you could cut the time to genetically select the right traits you want to get to in a few decades…if nothing goes wrong and everything goes perfectly. If you are lucky enough to have the precursor species your botanists know could become corn one day is something a scouting party could just find within the range they could get to realistically with whatever you build up.
Lots of luck would be required, and it would STILL take a hell of a long time to do just that. Getting steam engines and gliders and the like would take a long time too. And even with the magic portal back home, you are going to have very limited resources.
Can you please not pretend you’re not offended when you say something like " Sadly, you didn’t even grasp the argument I was making, as evident by this post, and since you can’t be bothered to keep things civil or even make a descent response I don’t see the point in continuing on this discussion."? It insults all of our intelligence.
Who is pretending? You clearly DIDN’T get it, and for all I know with this attempt to hijack the deflect you still don’t get it. Could you please either stay on track with the discussion or bow out? Seriously, I know you CAN give an interesting reply, as I’ve seen you do so in the past. Give one. Talk about the subject instead of trying to deflect to this sort of horseshit.
Or don’t. Totally up to you.
Guys, can we get this back to an interesting thought experiment? XT is pessimistic, or if you prefer, a conservative voice of reason that might keep the rest of us from getting overly optimistic and slaughtered by bears.
But the Roanoke failure is a bad example. That was most likely hostile natives and/or disease. Or aliens. And again, the stuff that whacked colonists (apart from natives) isn’t much of an issue here because we can just go home whenever we want or when we get hungry or the weather gets bad.