Black Magic - Intent, Fact & Knowledge

[LordDresden2]

  I think there is a WOJ that black magic corruption does not equate exactly with the 7 Laws of Magic.  The Laws are a simplification for use by the Council. 

Exactly.  There are obvious areas where the Laws don't fully match up to how the universe works.  For example, it's a near certainty that there is some taint associated with using magic to directly kill a White Court Vampire.  But the Laws are OK with it.  There's probably a little bit of taint associated with the 'gray areas'.  I would imagine Harry took a touch of taint when he animated Sue.  But it's OK under the Laws.  (Though if you do go around animating animals, I suspect you'd better have a very good reason or the Wardens will be looking for excuses to stop you.)

[LordDresden2]

From what Harry explain in book 9, it is simply a natural consequences of believing that killing is right. Magic only works when one truly believes in something. So when a wizard kill someone with magic, the wizard beleves that the kill is right, that it should be done, that it is right and proper.

That's not all there is too it.  If that was the whole story, genuine accidents with magic, even lethal ones, would leave no taint.  But they do have some effect.  Intent is a big part of it, though.

For one thing, pretty much anything usually gets easier the more you do it.  Even purely mundane things.  The 20th killing with a gun is usually easier than #1.  The third time you cheat on your husband or wife is usually easier than the first.  Even good things usually get easier as you do more of them.

Add in the amplifying feedback effect of magic...

[huangjimmy108]

That's not all there is too it.  If that was the whole story, genuine accidents with magic, even lethal ones, would leave no taint.  But they do have some effect.  Intent is a big part of it, though.

For one thing, pretty much anything usually gets easier the more you do it.  Even purely mundane things.  The 20th killing with a gun is usually easier than #1.  The third time you cheat on your husband or wife is usually easier than the first.  Even good things usually get easier as you do more of them.

Add in the amplifying feedback effect of magic...

Yeah, it is probably more complicated than what Harry explain in book 9. The human Harry killed during the wild hunt chase in book 14 for example. How does the taint works in that particular circumstances? 

but what Harry say in book 9 is probably the basics or at least one of the factors involve.

[Rasins]

Yeah, it is probably more complicated than what Harry explain in book 9. The human Harry killed during the wild hunt chase in book 14 for example. How does the taint works in that particular circumstances? 

but what Harry say in book 9 is probably the basics or at least one of the factors involve.

That's not all there is too it.  If that was the whole story, genuine accidents with magic, even lethal ones, would leave no taint.  But they do have some effect.  Intent is a big part of it, though.

For one thing, pretty much anything usually gets easier the more you do it.  Even purely mundane things.  The 20th killing with a gun is usually easier than #1.  The third time you cheat on your husband or wife is usually easier than the first.  Even good things usually get easier as you do more of them.

Add in the amplifying feedback effect of magic...

I think this is the heart of it.

[noblehunter]

The council say that killing non humankind does not violate the 7 laws, whether or not it cause taint however is another matter entirely.
 
Harry use forzare to kill the fetch in book 8, and he get lost in battle lust. The fetch is non human, but it is shown to us in book 9 that Harry's control of his temper is growing steadily worse by the day.
 
It is entirely possible that unjustly killing a supernatural being, say killing a bigfoot like river shoulders, will cause some kind of taint even though the council won't acknowledge the act as a law violation. It seldom happens though. When it comes to supernaturals and wizards. The ones who has good intentions won't come, and those who come don't have good intentions. The way things are going, it is well nai impossible to unjustly kill a supernatural.

A wizard has to be worried about more than just magical corruption. Morgan was a stonecold bastard and he followed the laws perfectly. Getting in the habit of killing things for bad reasons is going to do bad things to Harry even if he never gets near black magic. It's one of the reasons he'd rather have died than be the Winter Knight.

[Rasins]

Doing something makes doing that something again easier.  The more often you do it, the easier it becomes.

Black Magic amplifies this, and warps the practitioner.  This feeds into itself and has an addictive component.