I was tempted to say sight, I think because trying to imagine life without it is, well impossible. I think, though, that the truly important sense is touch. Think about it. There has been studies done on babies who have been properly nourished and so on, but never held or touched, many of them died before reaching maturity and those that did live were often mentally challenged. I worked with a woman who is autistic, she was raised in an institute from an infant. She was looked after, but because of the amount of patients in this place, she wasn't given individual attention. Just what she needed. She was, according to records, normal before she went into this institute. Also I have read (I can't remember where or when even) that some people who have lost their eyesight have learned to 'see' colors through touch. Consider the nature of healing. How many of you remember mom rubbing your belly when you were a kid and had a belly ache? It worked! My mom rubbed my back and shoulders when I was in the hospital with a wicked case of the flu. I felt better and almost went to sleep sitting up. Some may say 'it's psychological' and yeah, some of it probably is. But the thing is, touch is elemental. It's more than sight in that it's base, elemental, but also far more refined in it's gentler uses. Massage, Reiki, even just rubbing your lovers sore feet. It can be erotic, loving, soothing, relaxing, healing, it can tell stories (yep) convey messages, transcend languages. Touch is where it's at. People don't do enough touching anymore. Hugging, handshaking, thumb warring. So whenever you get the chance reach and touch someone. Just make sure you have a good lawyer.