A responsible person should at least evaluate all the possibilities. If its not possible then why even consider it? It comes down to proving that it is true, but how do you do that with absolute certainty? God "furnished proof to all men by raising Him from the dead" (Ac 17:31). Proof is an adequate degree of certainty about something arrived at by accumulating an amount of evidence which would satisfy a competent, unprejudiced mind. Reasonable people in ordinary situations would judge this. To call it true the results would have to be reliable beyond a reasonable doubt. Even though the conclusion might not be mathematically certain it will have a high chance of probability. It will be predictable and the result can be regularly demonstrated. Finally, faith is required to substantiate the premise.
The author of a Christian apologetics book believes that Christianity can be substantiated by relying on internal laws of logic and external laws of history and science. The scientific method starts with a hypothesis or premise of what is believed to be true. It can be tested and the results observed. Natural phenomena produce responses and natural laws are descriptions of them which results in a tentative acceptance based upon a predicted result reliably occurring. Active certainty is not claimed but the chance of the premise being correct is strengthened by the preponderance of the evidence supporting it. Inductive reasoning organizes the evidence such that the accuracy of the historical record can be determined and facts can be verified. Archaeology has continued to support Biblical descriptions and history has documented fulfillment of prophecies. Consequently the external inconsistencies of some religions create false realities.