Extraterrestrial Contact with Humans: is it real
Some people believe extra terrestrial aliens exist, others think these people are deluded. The evidence is ambiguous but indicates that the extraterrestrial aliens normally encountered are not beings from other planets. Examination of the question leads to the probability that extraterrestrial aliens are not encountered
What is an Alien
When asking if aliens exist most people have in mind physical beings from other planets, even other galaxies. Those who say these beings exist point to evidence of encounters with them, strange marks on the ground and abductions by beings in alien spacecraft.
This is a limited definition of an alien. Almost all the encounter cases involve humanoid aliens, usually with technology slightly in advance of the latest human technology, and thought processes similar to those of humans. Sometimes the aliens are robots, similar to those seen when ingesting DMT. There are also resemblances between todays aliens and the Sidhe, Leprechauns and other anomalous creatures from before the industrial revolution. Logically we have no reason to expect aliens to look human, or even be bipeds with a well defined head. And we have no reason to expect them to be able to communicate. As one writer said, If a lion could speak, we could not understand what they said for their relaity is too different from ours.
All this points to the encounter cases being largely figments of the imagination, probably arising from the collective unconscious. Cases involving strange marks could be misinterpreted or unconsciously caused by the witnesses. Each case has to be taken on its merits, but the hardest to explain seem to be those involving animal mutilations. At present the best one can say is that the evidence points in different directions.
It is perhaps more profitable to look at whether being with intelligence vastly alien to ours exist. Clearly we could not communicate with any being whose consciousness was radically different from ours. In fact we might not even be able to recognise such consciousness. How would we communicate with a mountain, a tree or the intelligent sea Stanislaw Lem invented in one novel.
Even if intelligent human like aliens existed, if they were sufficiently advanced they would find it hard to communicate with us. Think of how to explain Quantum Physics to a 12th Century scholar, postmodernism to William the Conqueror or the Free Market to Ivan the Terrible. Such people are no less intelligent than we are today, but we have so much more knowledge of the world that explaining today to yesterday will involve vast simplifications. It seems more likely such aliens will not bother without a good reason.
There is one alien intelligence most people claim exists, and it is called by various names, mostly God by Christians, with other names in other religions. By definition this is an unknowable alien intelligence, though most people give it human form and motives: Jahweh in the Old Testament for example would be regarded as a highly flawed human, and has human drives and motivations. Imperial China had a celestial court just like the earthly one and polytheistic pagan religions have gods that are little more than humans with super powers.
Kenny  analysed the western concept of God and had to abandon Omniscience and Omnipotence in order to obtain a consistent picture, though logically there is no reason to assume that “God” would be a logically consistent Entity.
Alien intelligence could also arise in machines, though this does not imply such machines are conscious, though consciousness seems to be a fundamental and irreducible aspect of the universe ,  so the possibility of machines being conscious in way we cannot know remains.
Terrestrial Aliens Morphic Resonance and Phantom Clowns
One obvious possibility, given that current science takes the speed of light as an upper limit to the speed with which matter and information can travel, and there is no way yet known to exploit the properties of complex space time which could allow two different points in space-time to coincide , is that the aliens encountered are local, that is from Earth.
This theory has a lot going for it, including the possibility that some UFOs are actually creatures that live in the upper atmosphere, perhaps descending to near earth levels occasionally, the possibility that the creatures involved are the Sidhe and other strange beings from folklore merely adapting themselves to modern times and our expectations: perhaps like Tinkerbell in Peter Pan, they die if people stop believing in them, or they need us for some other reason.
Alien encounters make more sense, though that is not necessarily a meaningful statement in this field, if considered as part of what John Keel termed The Phenomenon, referring to anomalous creatures, such as Hairy Monsters and Phantom Clowns , that erupt in waves, mainly recorded in the USA. Keel believed that we create and unconsciously control this. Some experiments have shown that recreating an event may produce anomalous effects , something that may be tentatively put down to Morphic Resonance.
Morphic Resonance and the collective unconsciousness together explain a lot. An odd event, possibly with a mundane explanation, is relived and retold and maybe recreated. With each repetition the universe responds with a similar event and eventually it gains a sort of reality that is independent of humanity. This could, for example explain why alien technology is never much more advanced than current human technology: airships in the 19th century and super hovercraft in the 20th, for aliens spring from our minds then become real. Perhaps indeed we create God in our own image.
The Question “Do Aliens Exist” led to consideration of the term “alien” with “exist” left for future study. Truly alien beings may be undetectable by us. Many people claim at least one alien being called “God” exists but give it human form and motives.
A broad brush view of the evidence for encounters with aliens suggests that these arise from the collective unconscious and may be related to wider classes of anomalies. Morphic Resonance and psychokinesis may explain why some waves of encounters grow and resistance, or simple loss of interest, together with a decline effect may explain why these flaps die away. However no simple theory seems likely to account for everything in this field
 The God of the Philosophers: Anthony Kenny, OUP Oxford; New edition (18 Dec 1986)
 A Paradigm-Breaking Hypothesis for Solving the Mind-Body Problem, Bernardo Kastrup, Paranthropology 3 (3) July 2012 page 4
 The Speed of Thought: Investigation of a Complex Space-Time Metric to Describe Psychic Phenomena ELIZABETH A. RAUSCHER AND RUSSELL TARG Journal of Scientific Exploration, Vol. 15, No. 3, pp. 331–354, 2001
 Monsters Among Us, Brad Steiger
 Phantom Clowns