YOU'D BE SURPRISED.
Are Firsthand Accounts More Reliable? (Anthony Le Donne, The Jesus Blog). Josephus was an eyewitness to much of what he wrote about, but contradictory versions of the same events in his works show him not to be a particularly reliable eyewitness. It is often (not necessary always) wiser to use circumstantial evidence and multiple accounts of similar events and situations to make generalizations about the past than to trust the veracity of any single account — even an eyewitness one — of any given event.