Signs/Headscratchers

Why a species that is capable of space travel across solar systems and avoiding detection couldn't just create a wetsuit to avoid that.
- Actually, they'd want a drysuit. A wetsuit is specifically designed to soak up water, let body heat warm it, and use it as an insulation buffer to the surrounding cold water. Drysuits are for use in _really_ cold or hot water, or in toxic liquids, which in this case is exactly what water is.
  - You're assuming that it would be easy to make a wetsuit? They rely on a lot of their natural advantages anyways, such as camoflage. Avoiding being hit and detected in the first place seems to be their greatest concern.
- Or maybe thay just didn't know that water would be toxic to them, because it doesn't exist where they come from - that would be a nice aversion for No Biochemical Barriers. Maybe they came to research the planet and were unlucky enough to discover the hard way how exactly they react to water.
  - Water is composed of hydrogen(the most common element in the Universe) and oxygen. It can't be that hard to figure out how to replicate that. Besides, we are a civilization incapable of manned interstellar travel at a feasible level, and yet we're perfectly capable of synthesizing elements, they surely must be able to recreate Earth's atmosphere for research purposes before invading.
    - Can't be that hard, huh? 'Kay, you do it.
- Water in any form is very common in our solar system alone. We've found it (not counting Earth) on the Moon, Mars, several of the moons of Jupiter and Saturn, Pluto, comets, and other places. Assuming that our solar system is fairly standard, how could they not be prepared for it?
  - Perhaps they have never encountered water in liquid form? Much of the universe is very cold. Most of those places that were listed in the previous entry were only found in solid (ice) form. Perhaps the aliens are from a very cold world and have had trouble creating liquid water anywhere outside of a laboratory, as was similar to the case with The Race in the Worldwar series of books. They had never encountered frozen water anywhere but laboratories or in very small quantities at the polar regions of their worlds, and were totally unprepared for the harsh, brutal winters of Earth.
- But this just raises further questions. They've been here for a while, so they should have prepared. Specifically, why go after humans, creatures that are eighty percent water?
  - Perhaps when water is mixed with other substances, it is safe for the aliens? Or, by some process, they remove the water from our bodies? We drink alcohol and smoke cigarettes, both of which are toxic to us, and it gives us trouble, but we survive.
Or why they were so sloppy as to leave a glaring amount of evidence leading to them.
- They might be hoping for misdirection. At first people were willing to say it was the work of pranksters.
- If you refer to the crop circles, I assume that they're directions to others of their kind, like "land here" or "stay away" or maybe even "we attack at midnight".
Or why they couldn't take any number of any other approaches (e.g. blanket bombing nerve gas).
- Assuming they have no material constraints and they can produces that much gas within an unspecified period of time. Or the fact they might have some kind of cultural attachment to hunting and some sort of code.
Or why they just turn out to be "crawling in the shadows to grab at you" monsters that can't break down a wooden barricade.
- Because they prioritise stealth above all else. They might not have known much about the basement anywasy so bashing straight in might be a tad bit too reckless.
- Also refer to the "ten-foot-jump" question and answers below.
Or why off-screen Earths armies were having trouble fending off an invasion by a race that can be stopped by a locked door and maimed with a kitchen knife.
- Possible Zerg Rush. I wouldn't say they had trouble fending them off when the aliens left after one night.
Or perhaps the biggest of all: Why would they try to invade earth when their whole invasion plan could be thwarted by a rain storm.
How is it that the aliens' legs can push them up to the top of a ten-odd-foot roof but can't kick down a wooden door?
- Being able to leap ten feet isn't necessarily a show of brute strength-what if the aliens were actually light in order to be more agile? They're a scouting force that's not meant to engage humans-think of them as space saboteurs rather than space marines that decided to try to impress their colleagues in the cities by capturing some humans-and failed utterly.
- Fridge logic of the trope here. The aliens are clearly on a raid for human beings (for whatever reason, all we know is that the guy on the radio said they dragged off the humans). Because to our knowledge human beings can't be found anywhere else (and indeed they couldn't be found away from water) the aliens picked dry parts of the earth to do a quick raid. Mist probably dosen't hurt them that bad, concentrated amounts of water are what really eats away at them (and even so, I think it was water mixed with being wailed on by a baseball bat from a dude who could clearly swing the thing pretty fast that killed the alien off) so if human beings are what they need then they risk it. This also explains why they didn't use rayguns or what have you as they needed the bodies at least mostly intact and death by asphyxiation would do minimal bodily damage (aside from y'know, the whole death thing).
  - Although one would still wonder why an advance race of aliens would go on a planet that rains a substance that is acidic to them without bringing a raincoat.
  - With their technology I'm sure they can predict when it will rain a great deal more accurately than humans can. How's this, though: their style is obviously stealth over warlike confrontation (hence their not attacking with ray guns or some shit), but they just continue to sit there, hovering invisibly over major cities, long after they have clearly been spotted. Really, in order to find all the Fridge Logic in this film one would have to take careful notes all throughout, and what's the point? Rule of Cool to the nth.
    - Um, no. Rule of Cool no longer applies when you're dealing with aliens that can be killed with water balloons.
      - It's a very common mistake to think that just because a species is technologically advanced, that automatically makes them competent at anything else besides technology, but this is a complete non-sequitur. Intelligence is a fluid, complex aggregate of many different things, some of which work for an individual and species better than others, and is entirely different from wisdom altogether. Look at what putzes human beings are for all our technological sophistication.
If they're affected by water, how come they do just fine breathing our atmosphere, which contains water in vapor form?
- It may be like the difference between breathing carbon dioxide in our atmosphere and holding a piece of dry ice-they're the same substance, but due to the temperature difference, dry ice hurts while the gas is harmless.
- Our atmosphere also contains things (Namely Oxygen) that are poisonous to us in the right concentration.
How exactly did the son come across a single book in their small town that gives accurate predictions of how the aliens will attack? Even if we do presume that it's supposed to be a warning from God it still requires a massive suspension of disbelief.
- Yeah, I guess that's what we're meant to take from it. The owner of the store said she'd gotten it by accident due to a mix-up with the delivery truck.
- Given that the book was, otherwise, entirely wrong about the aliens, and that its description of their possible tactics is extremely vague, the book was probably meant (by the filmmaker) to be something for the family to do while Merril made his visit to Sgt. Exposition.
What's always bothered this troper is how these aliens came god-only-knows how many light years to invade us, yet forgot to bring a single ray gun, or melee weapon, or you know, any weapons of any kind. Sure they had the cool gas thing from their hands, but that only seemed to work from arm-length range. Their invasion against the protaganists didn't go very well and that's with the heroes being relatively unarmed. Wouldn't it just be wholesale alien slaughter when they go against people with guns?
- The aliens in the film are a very, very small part of a global invasion. The main attackers are in the cities, and it's obvious that their technology is much more advanced-a news report says that a fighter jet flew straight into a (invisible) spaceship, and it did nothing. The aliens we see are basically a scouting force tasked with providing and maintaining navigational aids-the crop signs-and they're not supposed to engage humans in any way. With that said, it's not even a guarantee that the attack on the farmhouse was sanctioned by the higher-ups. It failed miserably, because they weren't equipped for it. The attacks in the cities were presumably successful because the invading forces were equipped and trained for it.
  - It's also possible that the attack itself was not the original plan, since they seem to be on a spy or fact-finding mission, and this is why they're so ill-equipped. Someone in charge goofed or went crazy. They never came to invade. Like the military guy said, it was obviously all reconaissance (sp?). As for the ones who attacked the farm house and especially the kidnapping: they were very likely out for revenge against the guy who mangled one of them.
    - It is specifically stated to be a raid and NOT an invasion. They are out to capture humans in a fair condition, albeit dead. If they used advanced weapons then then will be damaging what they are after but also it may force the world into a state of panic and they may arm nukes. The aliens were dumbing their combat down to an appropriate level so that the humans would respond in kind.
      - It's "specifically stated" by a guy on the radio who has no more real idea of the aliens' motivations than the Hesses do. You're applying random infodump logic from other movies to one that doesn't use it.
    - Who says they even have all this stuff? We tend to assume "if A then B" for all aliens based on our example. In this case, "if spaceships then rayguns". They may not have any ranged weaponry at all. Read The Road Not Taken by Harry Turtledove for an example of a race that has only advanced in one area.
      - If you can invoke Turtledove, I can invoke Niven: *any* means of propulsion can also serve as a weapon. If they have the means to transport ships across lightyears in the multiples, they have the technology for WMDs, too. And in general, it greatly stretches credibility that they can develop the means to cross the stars, without developing the idea of life support suits, or weapons, or any kind of comprehensible military tactics, or any of the other sciences and technologies that are vastly easier to develop.

( unless they were really demons all along, not aliens, which eliminates most of the fridge logic, but sadly not the lameness )

All of the above can be answered by the simple fact that Shyamalan was intentionally making a B-Movie with an A budget.
This was taken off the main page, so I'll put it here instead. So it's established that there are no coincidences -- it was a tagline for the film, if I recall correctly -- leaving us to conclude that God is responsible for basically everything in it. And if this is true, he is the epitome of jerkassery. He traumatizes an entire family and an Indian veterinarian in various ways before the movie even starts -- then either sends or, through omission of action, allows a significant portion of humanity to be abducted by aliens. All so he can save Mel Gibson's son from the asthma he gave him in the first place and somehow restore Mel's faith in God in the process. Would've made more sense if he'd hated God more than he did at the start, because his theory of random chance went out the window, making it entirely clear that there was a directing force behind all the crappy stuff that happens to him and his family and the entire world. Absolute wallbanger.
- "God exists" doesn't mean "God is nice." The big guy might just want people to believe in him, even if it means screwing them over. Sure, Mel might hate God, but when you know that some omnipotent being controls everything what options do you have other than trying to stay on his good side?
  - Yeah okay thanks /r/atheism.
- Before anything else, you're going to have to actually watch the movie instead of just sitting in the room fuming while it's on the screen. The point of the asthma was so that when he panicked at the alien's presence, his lungs would close and no poison would get in, not to cure him of the asthma. If you didn't even pay attention there's no point answering your questions.
When the Reverend Graham and Merill are boarding up Bo's bedroom, look closly. The door goes inwards and there is a cab caused by the frame of the door between said door and the boards. And the wer'nt. even that many boards. In conclution, the aliens would still be able to get in through that door.
- The boarding up of the house is not a calm, rational process where they have all the time in the world. It's being done in a near-panic, thinking that they might be attacked at any moment, with Merill desperately holding on to his courage and Graham halfheartedly holding on to his sanity. It makes sense that they'd make mistakes during it and not be thinking clearly... that's how the attic door winds up ignored.
What exactly were the military and police forces doing during this time? The movie makes only one mention of them the entire time, during the final newscast in which it is mentioned that ground forces are being mobilized across the globe. Yet, later, Merrill states that "a lot of people died". How, exactly? The aliens/demons really weren't that impressive. I've heard theories that perhaps they used very large amounts of their poison on population centers, but there's no mention of it. And again, where was the military?
- Military forces don't just appear where bad things happen. They have to be moved. And it seems likely they were moved in response to a potential threat before the threat materialized.... making it fairly easy for the aliens to attack where the military weren't.