I should of course have said «energy transported from the fire» rather than «energy in the fire». But, please, don't acquit the iceberg. Cold burns are just as serious as, and rather similar to, hot burns.
energy transported from the fire is a function of temperature and time (well, and the specific heat of the materials, but that is not part of the medieval experience... )
so essentially what you are arguing is that what matters is not temperature, but temperature...
Temperature as well as mass and contact surface, at least. A fire ball with little mass will burn out and lose heat before it does too much damage. A big fireball, resting against the victim and burning for hours, needn't be very hot to do serious damage.
So yes, temperature matters, but you do not necessarily have to increase temperature to do more damage.
thermal mass has some relevance, but far less than the specific heat- it would be more about how long you continue to do damage than how much damage you do. actual mass is pretty much meaningless, except that it tends to have some correlation to thermal mass.
of course since your fire in this instance is magically created it has an effective thermal mass of infinity, since any heat it loses is instantly replenished rather than being subject to conservation of energy.
Good point. It depends, of course, on the exact nature of the spell, but you are probably right that it is a better interpretation of pilum of fire and ball of abysmal flame than my initial, more physical, interpretations.
However, if you take the momentary duration literally, the temperature becomes irrelevant. Temperature can say much damage is done per unit of time, but with zero units of time, that formula does not explain any damage at all, so a different model is needed.
However that may be, contact surface (skin surface), or contact volume if the magic somehow has a deeper direct impact, remains as important as temperature. Burning your entire body is always going to be worse than burning your shoulder.
Momentary does not imply that no time passes at all, just a very short amount of time. It does however imply that all damage dealing fire spells with a momentary duration transfer their energy over the same span of time.
Momentary Duration can last as much as a full round, sometimes even a little longer. It varies by spell. Usually it's shorter than a full round, but not necessarily no time at all.
(ack, messed up the reply-to part and cannot see how to fix it)
Right. Happily, they've defined it for us, not just given if-then statements. Had they written just things like "a general spell allows...", we would have such if-then statements. But we're literally told exactly what it means, and then given later examples to clarify. But definition is even more powerful than just equality, and it is different than an if-then statement, not that you cannot make if-then statements about them.
And I never said it did. That was never part of the argument. The point is that, because they've given a definition, we know if we make such a spell it is a general spell. That does not imply all spells will fit the definition. For example, how would you make Conjuring the Mystic Tower more or less powerful? Bigger, more intricate, different material, etc. Sure. But more or less powerful?
Correct, the definition is more specific than that.
Actually, that is incorrect. As I pointed out above, they didn't just give an if-then statement. They defined it.
I'll call BS on this. Find me one guideline that says it's for a general spell. On top of that, there are even spells in the core book that are general spells and have no general guideline listed. We do know, however, that general guidelines can be used to build general spells. I.e. if you have a general guideline, then you can build a general spell.
So the issue is the statement "any level of difficulty — the higher the level, the more powerful the spell." What this does not say is what sort of function the increase must follow. It does say it must be monotonically increasing. It also doesn't say there cannot be a cap.
If there can be no cap, then it would be impossible to have Formulaic general spells because all Formulaic spells are limited to level 50 and so have caps on their levels. On top of that, we see guidelines that have caps, beyond which they don't do things. For example, look at Restore the Faded Threads. There is a cap to the guideline. It is even 100% by-the-book to make a D: Momentary version of it that is still a general spell and that will cap at level 45.
We also know that each level need not increase the power. Monotonically increasing is all that is implied rather than consistently increasing. Look at the same guideline. The power of the spell only rises every magnitude rather than every level. But that is sufficient. There are other general spells that have the same pattern of bumping up every magnitude rather than every level. So the examples have made it clear that consistent increase from a guideline is not necessary as long as there is a monotonic increase (is there ever not with matching guidelines?).
We also know you can build at intermediate levels, and from these guidelines we know it is not necessary for the spell to actually do anything more; you're just being silly doing it.
Now look at Spear of Fire. Whether the SG allows +1/level or not is irrelevant. +5/magnitude is sufficient. Whether there is a cap to the +damage fire (I don't think you reach any possible maximum before level 50 for a R: Voice spell anyway.) is irrelevant. We have a spell labeled "gen" increasing in power with levels. We have matched the definition of a general spell.
Your summation immediately above lays out almost exactly how I was thinking general level combat spells should work. Thank you for the corroboration.