connection to the hallucinations and is convinced that, rather than hallucinating, he is experiencing telepathy with an alien being. The being communicates to him that his home is being invaded and exploited by humans. Sam realizes that the other humans have been too closed-minded to realize this for themselves.

Sam reveals to Doctor Gentry that he had contact with one of the planet's inhabitants; the doctor reveals in turn that they were monitoring him the entire time. The Doctor considers him ill but grants Sam a meeting with the Commander. But Sam eventually convinces the Commander that neither of them have been hallucinating, that they were in fact communicating with a collective form of intelligence belonging to the insects on the planet.

The short story "Hallucination" by Isaac Asimov tells of a fifteen-year-old boy named Sam Chase who is sent to a planet where a team of people from Earth are drawing energy from a neutron star. Sam is puzzled at first because he has been assigned a position in gravitational engineering when his specialty is neurophysiology. Shortly after he arrives, he goes out on the planet's surface and makes telepathic contact with a group mind made up of the insect-like life forms on the planet. They are concerned that their home will be destroyed due to the human activity. Sam goes back and manages to convince the station commander to alter the mission to accommodate the local life.

This story has several important themes. First of all, it is a coming of age story. This can be defined as the process of a child becoming an adult. Sam comes to this new world feeling that a mistake has been made in his assignment. He has to learn how to fit in and find his place, and when he does, he discovers that he is there for a very important purpose. Before he can succeed, he has to stand up for his convictions and for what he perceives is the truth, even if it means that he might lose his place and be sent back to Earth. Once he takes this step, he is able to accept the responsibilities that come with adulthood.

Another theme of this story is alien contact and specifically the importance of open-mindedness and lack of fear when dealing with unknown intelligence. An alien mind has been trying to communicate with the humans even before Sam arrived, but it was not possible until someone approached it without fear and with the tolerance and acceptance necessary to be able to receive and interpret its messages. This applies in a larger sense to encounters that we have with people we may not understand at first. We have to have the patience and willingness necessary to open lines of communication.

Asimov also touches on the theme of technology as a benign force for good. Often in science fiction, technology is portrayed in a negative way, but in this story the central computer discerns the need and sends Sam to this outpost even though the humans don't really grasp at first why he is selected to go there.

Quick answer: The theme of Asimov’s story is that the misuse of technology and the abuse of the planet’s natural environment would inevitably lead to man’s demise. 

At the time Isaac Asimov penned his short story "Hallucination," the country was just coming out of an “energy crisis” and the Cold War was passing through one of its zeniths. Global tensions were running high, and environmental concerns regarding Reagan Administration polices were at a peak. Asimov’s story about a 15-year-old boy sent to Energy Planet to serve a three-year tour with a military unit responsible for facilitating the exploitation of other worlds to feed Earth’s seemingly inexhaustible thirst for energy could be considered an allegory about the need for sustainable development and more responsible approaches to man’s stewardship of his environment. It is also a warning against the misapplication of the advanced technology that seemed a preoccupation of the then-administration. 

Sam Chase, despite his superiors’ avoidance of the subject of hallucinations allegedly experienced by other inhabitants of this planet, is determined to explore their existence and meaning. Upset about his assignment, his immediate supervisor, Donald Gentry, admonishes his newly-arrived conscript about questioning the decisions of the machines upon which humans have come to depend: “Surely the Central Computer, which evaluated your scholastic record and your social and personal background can be trusted in its judgments.” Sam, however, is naturally inquisitive and, at the first opportunity, explores the planet outside of the man-made dome in which the humans live. The search for sources of infinite energy (“It was the magnetic field that would be tapped. Energy would be led away in enormous amounts and yet it would all be a pinprick, less than a pinprick, to the star’s rotational energy, which was the ultimate source. It would take billions of years to bleed off all that energy, and in that time, dozens of populated planets, fed the energy through hyperspace, would have all they needed for an indefinite time”) may dominate man’s purpose with regard to his expanding reach throughout the known universe, but Sam becomes convinced that this alien world has a different agenda. 

On his explorations, Sam discovers that the phenomenon that was interpreted as hallucinating was, in fact, the planet’s natural environment warning its human interlopers against manipulating the natural order, and that the “hallucinations” were the planet’s means of communicating with humans. Asimov’s story is intended as an indictment against man’s proclivity for expanding his reach and dominating his environment to the ultimate detriment of all. The plants and insects native to this planet will be destroyed, as humans have systematically destroyed their own native world. As his narrative continues, the author suggests the inevitability of such developments:

Human beings had built the Dome, cleared a large area of all planetary life and substituted their own. And once the neutron star had its power station—once floods of energy moved outward through hyperspace to power-thirsty worlds—more power stations would be built and still more. Then what would happen to Home... This planet was the nearest convenient base to the neutron star. It would be flooded with more and more people, more and more Domes, and their Home would be destroyed. "But you could change our minds if you had to, even if you damaged a few, couldn’t you?" If they tried, people would find them dangerous. People would work out what was happening. Ships would approach, and from a distance, use weapons to destroy the life on Home, and then bring in People-life instead. This could be seen in the people’s minds. People had a violent history; they would stop at nothing.

The military and political intrigues characteristic of the Cold War, during which much of the developing world had devolved into a chess board upon which the two superpowers maneuvered, was wreaking death and destruction across the world, and the competition and search for energy was destroying what warfare hadn’t. As Asimov’s protagonist, the innocent, inquisitive Sam, notes at one point regarding the mysterious force responsible for the hallucinations, “It wanted us to refrain from disturbing this planet. It wanted us not to take it over.”

The theme of Asimov’s story is that the misuse of technology and the abuse of the planet’s natural environment would inevitably lead to man’s demise.  Asimov knew enough about astronomy to understand that the long-term scenarios depicted in his stories, especially in "Hallucination," were too far removed from the present reality to provide a panacea.