Haptic technology in general not harmful to the human body and can be focused easily. One company called Ultrahaptics has been working with this technology to provide non-contact haptic feedback. Founded in 2013, Ultrahaptics has focused on providing users haptic feedback in free space using ultrasound technology. They use multiple ultrasound speakers to make changes in the air pressure around the user. This provides the ability to feel the pockets of pressurized air focused in the environment. This gives the user tactile cues for gestures, invisible interfaces, textures, and virtual objects. The company is continuing to grow and launched their evaluation programme
Analogy of the sun region in which truth and real being brightly shine, it understands and knows it and appears to have reason; but when it has nothing to rest on but that which is mingled with darkness—that which becomes and perishes, it opines, it grows dim-sighted, changing opinions up and down, and is like something without reason. ('The Republic, VI: 508d; trans. W. H. D. Rouse) The allusion to "...that which becomes and perishes..." relates to all of that which is perceived by the bodily senses. The bodily senses make it clear that all visible things are subject to change, which Socrates categorizes