The letters Ψ or ψ can be a symbol for: psychology, psychiatry, and sometimes parapsychology (involving paranormal or relating with the supernatural subjects, especially research into extrasensory perception). I want this as a tattoo.
“The broken triangle is an illustration of the Gestalt law of closure. The law of closure demonstrates how the mind creates wholes out of parts – and a world out of sensory information – by 'filling in the gaps.'” -- Love this as a very simple tattoo idea