Software-intensive science challenges in many ways our current scientific methods. This affects significantly our notion of science and scientific interpretation of the world, driving at the same time the philosophical debate. We consider some issues prompted by SIS in the light of the philosophical categories of ontology and epistemology.

We present a logic to model the behaviour of an agent trusting or not trusting messages sent by another agent. The logic formalises trust as a consistency checking function with respect to currentl...