Using Touch to Determine Degree of Roast
You can not touch the beans and feel the texture - but that texture can tell you much about the level to which it was roasted. Light roasts (City and City+) will have a bumpy texture and unevenness that you can actually feel. Darker roasts (Full City and Full City+) will have a smoother texture and even quality. Very dark roasts (Vienna and French) will have an oily surface that you can detect by touch.
You can crunch the roasted beans between your teeth and sense how firm or crumbly the beans are: lighted roasted beans are firmer, darker roasted beans are more crumbly.
The Macro Photos in this Roasted Coffee photo gallery give perghaps an exaggerated sense of texture but you get the idea.