Time-Turning (was Re: Snape and DADA)

[boyinleaves]

No: HPFGUIDX 112741

Why on earth would a wizard or witch find it unusual or paradoxical 
to be confronted with 'themselves' as a result of time travel? To 
these people, the unusual is commonplace, and can usually 
be 'explained' in some manner or another. They have Polyjuice 
potion! That could be one of many simple explanations for why 2 
Hermiones or two Harrys simultaneously exist. One of them could be a 
metamorphmagus, or be under some other appearance altering effect. I 
honestly can't understand why being seen by oneself when time 
travelling could be such a problem. Harry states that he would think 
he had gone mad, or that there was Dark Magic going on if he saw 
himself, yet this from someone who used polyjuice at 11, and finds 
magic more natural than anything in his life? Yes, it might be 
unusual to see ones time travelling self, but I seriously doubt 
anyone would kill themselves over it.

Oh, yeah, and according to these rules about time travel you guys 
have been hypothesising, specifically that time travel merely 
fulfils the sequence of events that have already happened, (which 
personally I believe IS how it works in HP), it shouldn't be 
possible to kill one's own past self, else how could one's future 
self exist to do it? 

Whew, this would make Hermione incorrect when she states "loads of 
them (wizards) ended up killing their past or future selves by 
mistake". They technically could kill their future selves, and then 
continue on, and return in time to be killed by their past self, but 
honestly, are wizards that stupid?

Okay, so here's a question for you. If you did happen to kill a 
future version of yourself that had returned in time, and then were 
faced with the possibility of returning in time, would the fact that 
you know what your past/future held/holds for you allow you to 
actually change the sequence of events? In PoA, Harry and Hermione 
don't know what the past/future held for their time travelling 
selves, so all they did was fulfill the sequence of events that had 
already happened. But if a time travelling wizard knew what his time 
travelling self would do, or had already done, would this knowledge 
place him on a different path, or would he still somehow be forced 
to fulfill his 'destiny'?

If you've ever done any freewill and determinism subjects in a 
philosophy course you might understand how terribly unfulfilling 
discussion of time travel and choice can be. I certainly do, but its 
fun nevertheless.