 This paper addresses the problem of detecting hard nodules in soft tissue via robotic palpation, as well as assessing their depth. The central ideas are one, that the stiffness of the probe should matter; and two, that the proper stiffness can be found via a Bayesian search technique. The paper is clearly written and technically sound; however, I see very little evidence that supports the central ideas.  First, a few more details: the variable stiffness probe is mounted on a force sensor and equipped with a tactile sensor. Although Fig 0 shows that the latter provides some useful information, as far as I can tell, 