Physical proof of alien abduction for Hopkins, came in the form of scoop marks, or indentations of the skin, scars or cuts on the mouth, nose, ears or genital, or unexplained bruises that might clear up in a day, and abductee claims of implants interpreted as control or monitoring devices similar to those used by (human) scientists to track and tag animals in the wild.
He also believed the alien spacecraft left marks on the ground where they landed and that the aliens could be photographed.

Anecdotal proof of alien sightings or abductions, which Hopkins considered "tightly imagined testimonies" by abductees, included victims' stories of observing unconventional objects in the sky, witnessing unusual activity (such as aliens digging for soil samples), flying through the air  or being transported to a ship, a sense of being watched or the presence of hooded beings near the bed at night, a sense of paralysis or immobilization while lying in bed or in their cars, impressions of flying or passing through closed windows or walls, a feeling of having been outside upon awakening, invisibility (both alien and human) and, most especially, a sense of missing or lost time.

Hopkins believed in his data collection techniques, as outlined in Missing Time, and insisted, despite questions from other researchers and skeptics, that his findings were solidly based in evidence that, cumulatively, was overwhelming.

Despite Hopkins' oft-repeated assertion of "powerful evidence" for alien abduction, critics plagued his career with calls for tangible proof, which were never forthcoming: DNA from the hybrid babies, proof of implants that were alluded to (particularly in the Cortile case) but never recovered, photographs or videotapes of space craft or aliens.
Critics, including his former wife, Rainey, expressed concern that UFO researcher leaders were not held to scholastic, scientific, or ethical standards.

Still others question whether it would be likely that alien abductors could actually float people through solid walls  and, if they could, wonder at how these people could escape detection, particularly in urban settings where there would, potentially, be millions of people around to witness the event.
Hopkins' response to the lack of UFO sightings by bystanders was to suggest that aliens could make themselves and their abductees invisible.

The lack of physical evidence and the inconsistencies and implausibility of the alien abduction stories lead some critics, including Carl Sagan and author Jodi Dean, to question whether these memories are the product of internal, rather than external experiences.
Physical proof of alien abduction for Hopkins, came in the form of scoop marks, or indentations of the skin, scars or cuts on the mouth, nose, ears or genital, or unexplained bruises that might clear up in a day, and abductee claims of implants interpreted as control or monitoring devices similar to those used by (human) scientists to track and tag animals in the wild. He also believed the alien spacecraft left marks on the ground where they landed and that the aliens could be photographed.
Anecdotal proof of alien sightings or abductions, which Hopkins considered "tightly imagined testimonies" by abductees, included victims' stories of observing unconventional objects in the sky, witnessing unusual activity (such as aliens digging for soil samples), flying through the air  or being transported to a ship, a sense of being watched or the presence of hooded beings near the bed at night, a sense of paralysis or immobilization while lying in bed or in their cars, impressions of flying or passing through closed windows or walls, a feeling of having been outside upon awakening, invisibility (both alien and human) and, most especially, a sense of missing or lost time.
Hopkins believed in his data collection techniques, as outlined in Missing Time, and insisted, despite questions from other researchers and skeptics, that his findings were solidly based in evidence that, cumulatively, was overwhelming.
Despite Hopkins' oft-repeated assertion of "powerful evidence" for alien abduction, critics plagued his career with calls for tangible proof, which were never forthcoming: DNA from the hybrid babies, proof of implants that were alluded to (particularly in the Cortile case) but never recovered, photographs or videotapes of space craft or aliens. Critics, including his former wife, Rainey, expressed concern that UFO researcher leaders were not held to scholastic, scientific, or ethical standards.
Still others question whether it would be likely that alien abductors could actually float people through solid walls  and, if they could, wonder at how these people could escape detection, particularly in urban settings where there would, potentially, be millions of people around to witness the event. Hopkins' response to the lack of UFO sightings by bystanders was to suggest that aliens could make themselves and their abductees invisible.
The lack of physical evidence and the inconsistencies and implausibility of the alien abduction stories lead some critics, including Carl Sagan and author Jodi Dean, to question whether these memories are the product of internal, rather than external experiences.
Budd Hopkins