John Thomas
Temporal Navigator
You can not enter your original past.
You can not alter it in any way.
If there was even the possibility of killing your grandfather, and you did kill your grandfather, you would not exist to kill your grandfather so this can not logically be possible.
You can enter an alternate past.
You could more easily view the alternate past without even entering it. For example, it is easier to view Mars right now than actually go to Mars. Possible reasons for entering this alternate past? You may wish to retrieve something valuable to you for your original future.
You can alter an alternate past.
If you enter this alternate past knowing that you can not alter your own original past, then why would you bother to help people in this alternate past if it does not benefit your original future? The answer is, what if you reread a book several times and wanted to rewrite it with a different ending? Or what if you wondered what it would be like if things were different for you in your past? Well trying to alter this alternate past would be like exploring these possibilities -- "What ifs". It would be a form of entertainment. You know what happens at the end of the book and so you inform characters in the book and they do something different. Then it's like you're writing then reading a new book.
You can live out your life either in your original future or your alternate future.
And here is yet another reason why you would alter this alternate past which does not change your original future. You can always chose to live out the rest of your life in this alternate past and your alternate future -- rather than going back to your own original future.
You can not alter it in any way.
If there was even the possibility of killing your grandfather, and you did kill your grandfather, you would not exist to kill your grandfather so this can not logically be possible.
You can enter an alternate past.
You could more easily view the alternate past without even entering it. For example, it is easier to view Mars right now than actually go to Mars. Possible reasons for entering this alternate past? You may wish to retrieve something valuable to you for your original future.
You can alter an alternate past.
If you enter this alternate past knowing that you can not alter your own original past, then why would you bother to help people in this alternate past if it does not benefit your original future? The answer is, what if you reread a book several times and wanted to rewrite it with a different ending? Or what if you wondered what it would be like if things were different for you in your past? Well trying to alter this alternate past would be like exploring these possibilities -- "What ifs". It would be a form of entertainment. You know what happens at the end of the book and so you inform characters in the book and they do something different. Then it's like you're writing then reading a new book.
You can live out your life either in your original future or your alternate future.
And here is yet another reason why you would alter this alternate past which does not change your original future. You can always chose to live out the rest of your life in this alternate past and your alternate future -- rather than going back to your own original future.