X-ray machines require both a source to produce x-rays and a detector to capture them. If human eyes functioned as x-ray detectors, it would be possible to see x-rays, but an x-ray source would still be necessary to emit them. The discussion emphasizes the dual role of x-ray technology in imaging. Without both components, viewing x-rays directly would not be feasible. Understanding this principle is crucial for grasping how x-ray imaging works.