.THE function of Bayesian contradiction to a series of lithologic parameters in an assessment of seismic information hardly seems to be right stuff of titles. But when the seismic data you are actually determining come from Mars, as well as when your reasoning advises that the most ideal description for them is liquid water in the pores in between rocks, you have a story. There is little people thirst for much more, when it involves earthly scientific research, than water on Mars. Why does the prospect provoke such pleasure-- and what performs this brand new analysis contribute to the tale?