"[S]ome... fragments are far from clear, and there are probably not a few of which the meaning will never be recovered. ...[T]he doxographers... are far less instructive with... Herakleitos... [T]he two accounts of... Herakleitos... in Diogenes, which goes back to the Vetusta Placita... is... pretty full and accurate. All our other sources are... tainted."