David Weinberger has an article at KM World on tacit emergence:

The most important tacit knowledge isn't simply explicit knowledge that hasn't yet been uttered. Humans aren't databases just waiting for the right queries to be run. The tacit knowledge that lets a senior technician diagnose problems faster and more accurately than others, or the tacit knowledge that lets a CFO see in 10 seconds why a proposed merger is unlikely to work, is emergent knowledge. It comes from a rich, confusing context of memories, heuristics and associations that the technician or the CFO may not be able to explain. In many cases, she or he will form a judgment incredibly quickly and only afterward will try to analyze why.

So, the attempt to make explicit the tacit knowledge in an organization may in fact be an attempt to short-circuit the chaotic process of emergence. But that's exactly what emergence doesn't allow. In such cases, a KM system can nourish the intelligence from which wisdom emerges but neither replace it nor make it explicit.