The article at hand analyses an often disregarded aspect of design science research that is how design knowledge is actually built or, more precisely, how new design knowledge is discovered. In the article we distinguish abductive and inductive forms of discovery. We describe how inductive and abductive discoveries are dealt with in traditional science and how these two forms of discovery have been discussed in Information Systems Design Science Research literature. By means of a case study we specifically illustrate the impact of a chosen mode of discovery on validity, utility, generality, and innovativeness of a problem solution. We find that the strength of inductively discovered design knowledge is that its validity, utility, and generality can be proven more easily than that of abductive discoveries. However, inductively discovered design knowledge often suffers from a smaller degree of innovativeness.