TruthSift is a cloud-based platform that logically combines members' contributions into a collective intelligence. Members add statements and directed connectors to diagrams. TruthSift monitors which statements have been logically established by demonstrations for which every challenge raised has been refuted by an established refutation. When members run out of rational objections, the result is a converged diagram succinctly representing the state of knowledge about a topic, including plausible challenges and how they were refuted. Previous computer systems for collaborative intelligence did not have a qualitatively better solution for combining contributions than voting and are subject to groupthink, interest group capture, and inability to follow a multistep logical argument. They did not settle issues automatically point by point and logically propagate the consequences. I review indications that many practically important statements most people believe to be firmly established will be revealed to be firmly refuted upon computer-assisted scrutiny. TruthSift also supports construction of powerful probabilistic models over networks of causes, implications, tests, and necessary factors.