diagram the argument (using the technique for making diagrams of arguments introduced in Chapter Five [attached in file below]), and discuss

diagram the argument (using the technique for making diagrams of arguments introduced in Chapter Five [attached in file below]), and discuss loopholes for each subargument.

Backward time travel will never be developed and used extensively by human beings

at any time in the future. For, if backward time travel were to be developed and used

extensively, then travelers from the future would be likely to visit our own time and

times already past. But since such visits should be readily detectable and since we

have no evidence of such visits we must conclude that such visits do not occur.