Taking the same power twice?

[Magus Black]

Ah I mean more of having Immunity to only Fire and Immunity to only Electricity with Supernatural Toughness (catch: water); that can all be researched. So it would sort of look like this:

Supernatural Toughness -4
   Catch: Water (+3)
Physical Immunity (Fire) -8
   Catch (Only Fire) +5
Physical Immunity (Electricity) -8
   Catch (Only Electricity) +5

Though perhaps I’m wording this wrong, I essentially am asking if having immunity to Only Two things (in this case fire and electricity) possible.

[toturi]

I am curious. How are the various elements used when there isn't any of the element apparently around?

Fire is easy. Unless you are surrounded by stuff at absolute zero or in the arctic or some such, there's always some heat around or the heat can come from you. Spirit doesn't really have a physical element unless you count light but evidently you can conjure up light when it is dark. Air is alright too, unless you are in some kind of vacuum.

Water and earth are the problem. Usually water. In place with no water or in some really dry place with low humidity, where's the water? Especially if you need really lots of water to achieve the effects you want: Water blast in the desert - where are you going to find the water to "Drench" someone with?

Entropic spells use the water element but does it actually cause water to physically materialise or is it, as I think it is, just a visual effect?

[John Galt]

Mostly just visual.  See the exploding tree example in YS to see how you bring your environment into play.

But in general you've limited your thinking too much.

Entropy is always around (water)
Heat is always around (fire)
Electromagnetic waves and gravity are always around (earth)
air is always around.

[wyvern]

Ah I mean more of having Immunity to only Fire and Immunity to only Electricity with Supernatural Toughness (catch: water); that can all be researched. So it would sort of look like this:

Supernatural Toughness -4
   Catch: Water (+3)
Physical Immunity (Fire) -8
   Catch (Only Fire) +5
Physical Immunity (Electricity) -8
   Catch (Only Electricity) +5

Though perhaps I’m wording this wrong, I essentially am asking if having immunity to Only Two things (in this case fire and electricity) possible.

You're doing that wrong.  The actual structure would look like this:

Supernatural Toughness -4
    Catch: water (+3)
Physical Immunity -8
    Stacked Catch: anything that's not fire or electricity +N

Now, the only question is, what's the value of N?  Specifically, does it get the +2 for only protecting against fire and electricity, or does it lose that since that's two things rather than one?  Were I GMing for you, I'd probably rule that fire & electricity is a sufficiently limited category of stuff for that catch to still be worth +5, but other GMs could easily argue that it's worth +4 or +3 instead (+2 for easy to get stuff that's neither fire nor electricity, +1 for researcheable, and maybe +1 for only protecting from a limited category of stuff).

[Magus Black]

You're doing that wrong.  The actual structure would look like this:

Supernatural Toughness -4
    Catch: water (+3)
Physical Immunity -8
    Stacked Catch: anything that's not fire or electricity +N

Ahh that for showing how that should be worded.

Now, the only question is, what's the value of N?  Specifically, does it get the +2 for only protecting against fire and electricity, or does it lose that since that's two things rather than one?  Were I GMing for you, I'd probably rule that fire & electricity is a sufficiently limited category of stuff for that catch to still be worth +5, but other GMs could easily argue that it's worth +4 or +3 instead (+2 for easy to get stuff that's neither fire nor electricity, +1 for researcheable, and maybe +1 for only protecting from a limited category of stuff).

Yes that is, ultimately, the question that ask! Normally Physical Immunity works of being Immune to everything ‘except’ the catch (EX: Immune to everything but Fire) and on the opposite matter is when your immune to only one thing, and get the +2 Refresh bonus (EX: Immunity to only Fire). This turns out to be a strange middle ground in which you aren’t to immune to only one thing, but also are also not immune to everything except that one thing.

One of the reasons I ended up writing it up wrong in the first place is because it fits neither category, and brings to question as to whether its worth a total of -16 Refresh or just -8, and whether its possible to gain the Stacked Catch bonus as well.

[Korwin]

I would give it the +2 Bonus for "only against one thing".
If I compare Immunity against Fire and Electicity against Immunity against Guns or Immunity against Magic, it doesnt seem overpowered.