It is conjectured that the only way a failure detector (FD) can help solving n-process tasks is by providing k-set consensus for some k ∈ {1, . . . , n} among all the processes. It was recently shown by Zieliński that any FD that allows for solving a given n-process task that is unsolvable read-write wait-free, also solves (n − 1)-set consensus. In this paper, we provide a generalization of Zieliński's result. We show that any FD that solves a colorless task that cannot be solved read-write k-resiliently, also solves k-set consensus. More generally, we show that every colorless task T can be characterized by its set consensus number: the largest k ∈ {1, . . . , n} such that T is solvable (k − 1)-resiliently. A task T with set consensus number k is, in the failure detector sense, equivalent to k-set consensus, i.e., a FD solves T if and only if it solves k-set consensus. As a corollary, we determine the weakest FD for solving k-set consensus in every environment, i.e., for all assumptions on when and where failures might occur.