Dr John Martin
Water is wet because we perceive it to be, it cannot be just due to learning and experience or else it would be different for everyone. When two sensations are combined, that of light touch and coolness, we perceive wet. This has been studied since the 1800's and this illusion (Thurnbergs Illusion) of wetness has been replicated with cold metal disks. When you place a cool metal disk on someone's forehead they often perceive it as water, perhaps even expecting it to drip.
