Legal Question in Business Law in California

Statements of fact made in a motion are entitled to a presumption of truth unless they are so obviously false that they are simply not credible at all, such as "Next Thursday, which is Good Friday....." The practice of law has various techniques for challenging the truthfulness of assertions made in written pleadings or at oral proceedings such as motion hearings or trials. Sometimes the appropriate method involves formal "discovery" such as taking a deposition or serving written interrogatories; at other times it may involve cross-examination of a witness or filing an opposition pleading which points out the other side's failure adequately to prove facts alleged in the other guy's pleading. In the case of a motion to overturn a default judgment, I'd think the challenge starts with filing an opposition pointing out claims that are unsubstantiated and/or facially improbable. It may be relevant to know whether the "facts" you believe untrue are things within the opposing attorney's knowledge, such as why he failed to act in a timely fashion, or things within the client's knowledge, such as where he hid the evidence.