Combine half of the raspberries, the sugar, and 1 tablespoon water in a small saucepan. Stir over medium heat until the sugar melts and the mixture comes to a boil, about 5 minutes. Turn off the heat and fold in the remaining raspberries and transfer to a bowl to cool. (This can be made several days in advance, and stored in an airtight container in the refrigerator.)
Peel and core the pears. Cut each pear into slices. Sprinkle with a little sugar and allow the pears to sit for a few minutes to release some of the fruit's juices.
To serve, divide sliced pear between 4 stemmed glasses or tumblers. Place about 1/4 cup raspberry sauce on top, and top with one generous scoop of sorbet. Serve immediately with cookies or shortbread