Is there any possibility that a species more intelligent than human exists on earth?

The simple answer is:  remotely possible, but EXTREMELY unlikely.

Let's break it down:

Are there supernatural creatures inhabiting a spirit plane that envelops the earth, observing us and occasionally interacting with us in mysterious ways?

I don't know, but I see no evidence for it.  On the other hand, there are billions of people who will insist that the answer is yes.

Are there alien life forms that have travelled to earth but have chosen to hide from us?

Uh... maybe?  It doesn't seem very likely that an intelligent alien would come all this way just to watch "Orange is the New Black," but who the hell knows?  They're ALIENS.  If they exist, they presumably don't think like we do, so we can't guess at their intentions.

Is there some intelligent species on earth that has learned how to perfectly transform itself into other life forms and is choosing to "pass" as human beings?

Fun idea, but ridiculously improbable.  It would require a level of were-shifting able to survive even the most detailed autopsy and gene scan, and if they're identical to humans at that level, then they ARE human.

Even if such a thing as true shapechanging were possible from an evolutionary point of view, the evolutionary pressures for superb metamorphic capabilities and for high intelligence are simply not compatible.  Although the mimic octopus is suggestive of ways intelligence can be expressed through mimicry, do note that this is only mimicry, NOT true shape changing!  :)

Are there any other species that have reached our sophistication in terms of communication, problem solving, and engineering?  Certainly not!  However, I believe that it is possible that other species are "more intelligent" than humans in very limited respects.  For example, a chimpanzee was actually able to outperform college students in a simple working memory task.  See Chimps beat humans in memory test.  While another study (Page on claimed that the comparison was biased due to the fact that the chimpanzee had more practice than the humans it still shows that a monkey can compete with human in a purely cognitive task.  I wouldn't be surprised if other animals were similarly able to rival humans in limited cognitive tasks.

It is my personal belief that our language abilities provides a major leap forward in our overall intelligence.  Language not only allows advanced knowledge to be passed from one individual to another it also allows us to think abstractly.  For example, the Pirahã language does not have words for specific numbers.  As you can imagine, speakers of this language had a worse capacity for remembering quantities than English speakers (Page on  Without being taught words for numbers you may be able to perform simple addition but I highly doubt you would be able to do more complex arithmetic like division, much less complex mathematics.

See also Does a broader vocabulary allow you to think faster?
My answer would be that it is highly improbable for reasons already explained by the brilliant Shakti Amarantha.

Is it possible for a more intelligent species to be co-existing with us? Well, almost anything is.

Let me explain one possibility.

All of us have heard of Arthur C. Clarke's oft-repeated assertion that "any sufficiently advanced technology is indistinguishable from magic." Personally, I've always found that reasoning to be somewhat clumsy

Just recently, Canadian science fiction writer Karl Schroeder has come up with a modified proposition: "any sufficiently advanced technology is indistinguishable from nature."

Could some of the species living on earth have actually been engineered by a supra-intelligent exo-civilization? That's certainly food for thought.

Consider the electron-microscopic image of a gear below:


Humans are most intelligent?! . It is just our ego that makes us feel so.

Just look around , humans are the only creatures that damage the earth. A tree is much more useful to nature than a human being.

We have melted glaciers , we have affected the ozone layer and so on.

We are all miserable , we keep searching for peace but find none. We fight , we kill , we do war , we are sad , we are depressed , we commit suicide. Does any other creature does drugs ? Does any other creature commits suicide ? Does any other creature rapes? Does any other creature has the need to meditate ? They are already meditative and in sync with GOD. Its humans who have to do soul searching , make concepts of karma and God , do meditation , make temples just to console ourselves. Humans are always dissatisfied , discontent , pathetic , miserable , seeking for more and more , greed has taken over our intelligence. Every creature is singing its own song , but we humans are pretentious , we want to impress others , we want to prove our point to others , we have all boarded a wrong train , we are crying that we are on a wrong train but are not getting out of it.

We in fact have the lowest intelligence of all creations , until of-course we realize the true nature of our own being which is peace and contentment. Till then we are pathetic!

I belong to you ! Thanks.

I think, there is an invisible lifeform which is also more intelligent than humans. Like many lifeforms feed on each other on earth, this one feeds on humans. When their feeding time comes they eat, but not same as we do. They suck our life energy and we think we just died. (or we cannot think) They are so clever, they even write a death scenario for us. For example; one man is climbing a pole, one of them goes to the top of the pole and the other one waits on the ground. The top one pushes the man and the one on the ground catches his life energy. We think the man died because he fell from the pole. They are the real reason of wars, accidents and all the other death causes. Otherwise humans wouldn't die normally, if they didn't exist. They have one more talent. They can take over a humans body for a while, they make him cause an accident then they leave the body after they suck humans life energy. After they take over a humans body theycan cause that human to have heart attack as well.
They don't attack the animals because the main reason why they feed on humans, is humans' intelligence. Doing so makes them more and more intelligent and gives them more life and making them immortal gradually.... They even exaggerate and take over humans to make them reproduce more and more, so they never run out of food. They can even push thoughts into our brains remotely to make us commit suicide...
Now you will ask me how I came up with this idea. I simply looked at our world and saw creatures which can fly, swim, walk, run. A chameleon can make itself nearly invisible, there are many lifeforms which can camouflage. There is eel for example which has electric in its body. There are bats and mosquitoes which suck your blood like a vampire. (There were too many different types of dinosaurs on the past). There are even more lifeforms like; poisonous animals and plants, insect eating plants, plant eating insects, too many cannibal animals, bacteria, viruses and there are humans who eats animals, plants, bacteria and most of the things. If all of these exist, I don't see why another lifeform superior to the humans shouldn't exist. They saw what's going on earth and they evolved this way. It would be difficult for them if they weren't invisible. Humans would fight against them. Who knows, maybe they evolved from humans?
I think they exist and there is nothing we can do... (Maybe in the future.)
I even have a name for them : "THEY"

Thank You for reading...

The problem is, to the extent we define "intelligence" at all, it's in human terms. In fact, there's no agreed-upon definition, even by experts, but if we pick one like "ability to score highly on IQ tests," it will be biased towards humans, because humans make those tests to score other humans.

There is almost certainly no species on Earth that is smarter than we are in terms of chess-playing ability, solving calculus problems, writing creative fiction, inventing tools, and so on. We don't have a scrap of evidence that such a species exists, and we have lots of evidence that it doesn't. This brilliant species has left no signs of itself--on a planet where it's getting harder by the day to escape detection.

Like us, that species would have had to become intelligent slowly, over millions of years, with earlier versions of it being less-intelligent but still very intelligent. Yet we've seen no signs of them (on a planet where there are fewer and fewer places to hide) and we have to archeological evidence of them having ever existed. (On the other hand, we do have signs of earlier, intelligent human species. We've found their tools and their cave drawing.)

The idea that a few lone Einstein-like dogs or monkeys could be hiding in a cave somewhere isn't really possible, given the biological requirements. A birth defect, exposure to radiation, or a knock on the head can't boost an animal's intelligence to great heights.

That said, my cats are much better at tracking objects than I am. That is a cognitive skill. If you stuck eight arms on me, I wouldn't be able to manipulate them like an octopus can. That's also a cognitive skill. Many birds have an amazing ability to navigate over long distances without radar, a compass, etc. I get lost three blocks from my apartment.

The truth is, various species have different sorts of intelligences.

If light has a particle (photons) then why can't we capture and study it?

Light is strictly equivalent to the notion of Big Bong. Both of them are the place where the amount of subdimensions is near to 4. Since the Universe is relative, the notion of

Is there scientific proof of demons?

There is no evidence that supernatural entities known as demons are real and actually exist. There are of course many stories. The concept is also a powerful religious idea that helps people to explain some things; hence the idea thrives and persists.Many belief systems claim that unseen hidden supernatural entities are real and explain

Is it normal (in our galaxy) for stars to be as far apart as we are from our nearest neighbor? Would a closer proximity of another star rule out life (carbon-based)?

The average distance to other stars varies depending on where you are in the galaxy.The star density near us is quite typical for the spiral arms.In the center of the galaxy stars are much closer together. Proximity of another star does not have to spell doom for carbon based life. Several binary star systems