All thumbs The cleverest human features come in pairs like eyes and ears like testicles and breasts and so too with opposable digits supposed to be the most definitive trick of our species a smart device that assists fine motor skills and brings precision to our fidgets. You’ve taken it all for granted over the years when time has been neatly jointed but as each hinge at the base of those paired phalanges starts to go numb and then succumbs to acute arthritis the sight of a screw-top jar or a weedy patch of garden fills you with winces…