  Because closed timelike curves are consistent with general relativity, many
have asserted that time travel into the past is physically possible if not
technologically infeasible. However, the possibility of time travel into the
past rests on the unstated and false assumption that zero change to the past
implies zero change to the present. I show that this assumption is logically
inconsistent; as such, it renders time travel into the past both unscientific
and pseudoscientific.
