So you're in the desert desperately thirsty; you're fairly certain that you see water in the distance. That doesn't mean you'll get water -- you may die before

So you're in the desert desperately thirsty; you're fairly certain that you see water in the distance. That doesn't mean you'll get water -- you may die before getting there, it's a mirage -- but it's gotta mean that water exists for why else the driving, maddening, desire to drink? Not talking about achieving, just talking about existing... remove all religious overtones (or undertones); just on a purely practical level -- if there was no such thing as water would you ever get thirsty?