On p114 under Changing Duration, Ranges and Targets it says (unhelpfully) that 'below level 5' adding a magnitude only adds a level.
Below level 5 of what? Base effect? If that's the case can't it say that?
Notional spell level at that point in the calculation, apparently. I think it's clear from the examples -- though one should never have to rely on examples to understand the Letter of the Rules.
See the discussion I've been having in your: thread on personal range.
So, if I understand this, if you have (say) a MuCo spell to change someone else's appearance it might have a level of 6 which would be worked out as a base of 3 (see MuCo guidelines) +1M for "Touch" +2M for "Sun" +0 for "Individual".
There:
3L+1M=4 (increase Range to Touch)
4L+1M=5 (increase Duration to Concentration)
5L+1M=10 (increase Duration to Sun)
If you wanted to reduce the cost by, say, reducing the duration to "concentration" you would be reducing a level 10 spell by 1 magitude, giving 1. If you then wanted to apply the spell to yourself ("Personal") rather than another character ("Individual") you would be reducing a level 5 spell by one magnitude and getting 4.
I don't like the sudden irrational jump in cost at level 5. It strikes me that this is a rules crock to prevent changes in Range, Duration and Target from being too extreme for very low-level spells. It would have been simpler and more easily understandable to say that the spell cost was increased by (say) 50% for each extra jump in RD&T ... though that would make boosting very high level spells really expensive (which might not be a bad thing).
... however, them's the rules.
But but but....
I'm sorry that makes no sense. It only seems to work if you start out with already calculated examples. Surely the rule should work from how you design each spell in the first place, starting with base effect level and then modifying it....
No, no, I'm sorry I'm babbling. I'm trying to figure out what the rule would be if it were explicitly stated and I can't....
Maybe I'll go and lie down and not think about role-playing games for a few days and then I'll feel better....
Think of it as a sequence of numbers. Start from the base as given in the guidelines. Modifying range/duration/etc move the level one or more steps along this sequence.
1-2-3-4-5-10-15-20-25-30-35-40-45-50-55-60-(+5 each step from here)
Non-intuitively, the sequence isn't quite linear, but it has a break only in one place: at level 5.
OK, I'm not trying to start a flame war or anything, but what else would "level 5" refer to?
Yes, some of the rules don't completely make sense unless you read the example spells. That's why they're there. It's much more space-efficient to be able to point to examples of what's going on.
My advice? Don't jump into the game trying to design all-new spells for every character. Start with the printed stuff; it's really pretty good. Once you've got a feel for when to use CrTe versus PeIg you can start making your own spells. I'd hold off on getting fancy with magic items right at first; that can be very confusing, especially if you're making several alterations to the base spell (or, YHVH forbid, using your own).
Space efficient is not brain efficient. Not my brain anyway. And the very first time someone tries to cast a spontaneous spell the GM has to know how to calculate the level of it. About five minutes after they entered Calebais, in my case.
That's the best way to describe it I think. Does this explain it now, Michael?
You would apply it as follows:
To illustrate his point about the transience of magic, Herbert Magus casts a spontaneous spell to create an apple.
Looking at the guidelines, creating an apple has a base level of 1. He's going to create it in his hand so that's +1 for tough and he only wants it there while he concentrates, so that's another +1 (I think).
Create the Transient Fruit
CrHe 3
Touch, Conc, Ind
Create's an apple in the palm of the caster's hand. The apple can be taken from him, eaten, anything that can be done with a natural apple, except that the apple fades from existence when the caster stops concentrating on it.
(Base 1, +1 Touch, +1 Concentration)
So there you are. Below level 5, just add one level.
Now, if he wanted to create an insect in the same way, the base level would be 5 and adding 1 for each of Touch and Concentration makes a level 15 spell. As the base level is 5+ you treat each increment as a full magnitude.
It's just a mechanic to ensure that really simple spells aren't needlessly hard to manage.
That isn't (if I understand you correctly) saying quite what I mean by 'base level of less than 5'.
Let us take an InVi spell of Base level 4 (to detect spells of 3rd magnitude or higher). If I add sight target (the target of Intellego spells being the sense affected as noted in another irritating thread I've started) then that's +4m. Which if we're working off base effect level makes 8 levels but according to your scale there are no such things.
I'm complaining that if you're right the rule doesn't express clearly what is meant. (Actually, even if you're wrong the rule doesn't express clearly what is meant.)
I'm sorry if I'm being dim but what I'm seeking is a fully written out explanation of how the system is supposed to work in plain English that I can understand.
It seems at the moment that your are pursuing two aims simultaneous: To get an explanation of how the rules work, and to complain on the way they're phrased in the rulebook.
For the first part I think Wolf and Mark offer you some good and covering explanation. Simply put when ever you add extra magnitudes (from increased Range, Duration, Target, Size etc) to a spell you add one at a time, regardless of how many you have to add. Each mangitude is translated into levels one a one-to-one basis untill your reach 5, at which point you add them normally (one magnitude = 5 levels). Even if increasing Duration from Momentary to Sun, which is two extra magnitudes, you add them one by one. The theoretical picture for your mind's eye could be that you're first upscaling the power from Momentary to Diameter, and then from Diameter to Sun. Please ask if their efforts, and mine here, havent sufficiently been able to clarify it or if you have any further questions to it.
For the second part, it is a different subject that might be in process of getting too much intertwined with the first part. I dont think you will find it clearer elsewhere in the book than it already is. To some degree it is also a matter of preferences, but if it is to your dissatisfaction I am pretty sure Atlas and David Chart would value a direct mail with your points, which they might take into account when making erratas. The rest of us really cant change the way the RAW is written - only help you interpret it. They do have a good track record of listening to people and keeping a close connection to the players of the game - hence this forum.
You are quite correct in that. My irritation is probably due to the fact that I have to look my players in the face (some of whom are being quite hard to sell on this game system and setting) and be confident that I'm not making an idiot of myself with the rules. You will note that your explanation is considerably longer than the sentence in the main rule book.
Your explanation is the fullest and clearest I have received. However, I still can't reduce it in my head to a short and easily retained rule.
Okay, so use the base 4 as an example.
Detect the flash of Magic
InVi 20
Personal Momentary Vision
The caster sees a flash of emanating from any active Hermetic spells or device effects of 3rd magnitude or higher.
(Base 4, +4 Vision)
So, how did I get level 20? Well, 1st magnitude covers spells up to level 5. We've already covered some of those. 3rd magnitude covers spell levels 11 to 15 inclusive.
The rule is, while the spell level is less than 5 you treat additional magnitudes as level increments. So, where our base is 4 and we want to add 4 magnitudes we see the following
Base 4
+1 = 5
+1 = 10
+1 = 15
+1 = 20
See what I did? Apply the +4 in steps of one magnitude each. On the first step the base level is 4, which is below 5, so we just add one level. By the time I add the second increment the level is 5 so I know I need to add a full magnitude so the level is 10. The same is true of the last two increments and they add 5 each for a level of 20.
Don't worry. This will sink in and it will become second nature.
But, I hear you ask, are there any exceptions? How do device effect levels work? They sound like they might make things waaay too difficult to enchant.
The good news is (and read this only after you've fully understood the section above) that device levels are easy. They are exactly that, levels.
So, I want to enchant my talisman with the above InVi effect (that way I can use the Personal range and it keeps our example simple). I'd like to be able to use it 10 times per day.
Looking at the effect frequency table (ArM, page 98) I see I can give it either 6 or 12 uses. I'll go for 12. That gives +4 to the device level.
So, I have a level 20 effect + 4 levels for a device effect level of 24. They didn't add as full magnitudes. If I wanted to restrict the use to myself only (so I'm the only one that can trigger it) I'd add +3 for a grand total of 27.
Again, this will sink in and will become second nature.
Well - I'm glad that I'm neither a line editor, writer or a new player. I've bought and treasured the game since two editions prior to this one (though I didnt get to play untill a the current saga starting a few years back). I havent had to read the rules entirely from scratch nor have I had to try to write them so that fresh eyes would instantly get them - on top of redesigning for the better. On the other hand, even after having read 5th edition back to back I missed some changes in it, but that is definately because I had another handicap - predisposed with earlier material.
And were you are at at the moment you might not believe me (or others might not agree with me) but one of the things I treasure about Ars 5th edition is its streamlining and the vision of the whole line.
As for rules at hand - you can just ignore any spell that wouldn't crawl above level 5 and just fix them at 5. What I do is thinking of it more like a ruler in my head that I count along when adding magnitudes rather than actually calculate them - makes it all very simple (1 bottle, 2 bottles, 3 bottles, 4 bottles, 5 bottles, 10 bottles, 15 bottles, 20 bottles of vis on the wall). Just as when starting a car the acceleration speeds up at some point (unless you drive a brand new fire-engine with turbo-injection 
) - only numbers you have to remember is 5 and 50. 5 because of the magnitude shifting and 50 because you'll soon have to whip up a grand ritual to manage.
Yeah - if not first nature... and that is the point where you start to freak yourself out.. 
How about this...
There are actually three separate scales, Magi Magnitudes, mechanics magnitudes and Levels.
Unfortunately mechanic magnitudes are refered to both as levels and as magnitudes in the rules. This is because the basic guidelines, if kept in simplest form, provide a spell of that level. Yet each additional increase will usually provide an increase of one magnitude (once the overall level of the spell has exceeded 5).
Levels, are purely for players and some of the mechanics and are perfectly linear, You can have level 1, level 2, level 3... level 6...level 10... level 17... level 50... level 51... level 187...
However, real magic isn't quite so precisely defined - its an Art after all. Magi talk about Magnitudes - "such an such a spell is fourth magnitude, however my covenant has an interesting variant at fifth magnitude that allows casting on a small group rather than a solitary individual."
Magnitudes, are Level/5, rounded up. A level 3 spell is first magnitude as is a level 5 spell. A level 6 spell is second magnitude. A level 37 spell is 8th magnitude, as is a level 40 spell. These 'Magi Magnitudes' are conveniently also exactly the amount of vis needed in ritual spells.
Where it gets complicated is calculating the Level of a spell - because in order to balance very low level spells, at very low levels the mathematics used are different and the terminology is, perhaps, poorly applied - hence my use of the third scale, mechanics magnitudes.
When calculating the level of a spell, all the guidelines are based on mechanics magnitudes. However, mechanics magnitudes are not the same as Magi's Magnitudes because the calculation system to convert from mechanical magnitudes to Levels goes 1,2,3,4,5,10,15...
This works in practice, once you have your head round it, because most of the interesting things Magi want to do, and want to mess around with expanding, modifying or multiplying effects, are already above 5th Level, and thereafter each mechanical magnitude increase equates exactly with one Magi Magnitude increase.
So back to your example...
So using mechanical magnitudes we have Starting position 4, +4 increases = 4->5->10->15->20. A level 20 spell, or in Magi-speak, 4th magnitude.
Its a little bit like counting in a non base 10 system.
Base / equation / result
Levels /4+4 /Level 8
mech magn /4+4 /Level 20 (Magi Magn 4)
Magi Magn /4+4 / Magnitude 8 (level 40)
base 10 / 4+4 / number 8
base 6 / 4+4 / number 12
The other mildly compliction factor is that when enchanting effects, additional levels can be added that do not relate to the spell, but to the arrangement of the spell (eg, uses/day, additional penetration, triggers etc). So when enchanting you can have a spell with effect at Level X (magnitude X/5) which is enchanted at level Y (X + extras).
Erm.... Eh?
My thoughts exactly.
Xavi
Speaking in spell levels, level 4 + 4 levels = spell level 8
Speaking in "mechanical magnitudes" (the ones used to calculate spell level): Base 4, + 4 magnitudes = spell level 20 (4 -> 5 -> 10 -> 15 -> 20)
Speaking in Magical Magnitudes, a spell of 4 magnitudes (spell level 20), + 4 magnitudes, becomes a magnitude 8 spell (spell level 40)
Speaking in base 10 (our system of counting), 4 + 4 = 8
Speaking in base 6... is difficult because unfamiliar. 4 + 1= 5, +1 = 6, +1 = 10, + 1 = 12.
Just like, in base 2, 2+2 would equal 2+1= 10, +1 = 11.
The question is: how does all those unnecessary maths CLARIFY and make EASIER the issue at hand in this thread? 
Xavi
What I finally sent to my player was:
The system for calculating the level of a spell is slightly wacky and highly fudged. And, in my arrogant opinion, impossible to work out from the rule book.
If the base level of the spell is 5 or above then add 5 levels per additional magnitude caused by Range, Duration or Target.
However if the base level of the spell is below 5 then add one level per magnitude caused by R, D or T until the total level is five and then add levels at a rate of 5 per magnitude.
This means that possible levels of spells go
1,2,3,4,5, 10, 15, 20 etc....
This is a horrendous bodge.
Leaving out my editorial comments does that actually communicate what the rule is?
I don't think it is possible to leave aside the editorial comment. It isn't a bodge. It's there for a reason. It is possible to gather the rules from the rulebook, it's just that, as you discovered, some of them may take a little reassurance that what you've gathered is correct (or wrong...).
The thing is, it's like any game system in that there will be areas that don't sink in as quickly or seem counter-intuitive. I still don't understand about actions, full actions, free actions, and half actions in D&D. Others find that really simple and look at me askance when I confess my confusion.
The bottom line is, don't worry. The rules aren't bodged together. There is always a logic to it. Spell levels start low and then get higher so that small effects are really easy to achieve. Extending a spell out to Arcane Connection, Moon, and Group (then adding some for size etc) soon gets pretty hard so enjoy the fruits of lower level spells.
If there's ever anything that isn't clear there's always someone here to help you through it but if you are describing (or approaching) the rules as bodges with your playing group I think you're doing yourself and the rules a disservice.
I agree with Mark.. it's not a bodge.. and I have to say, I didn't find the ars rules difficult to learn at all.
As mark says.. the reason it's like that is so you can make small effects with a low level.. .. in a game with spontaneous casting, you NEED to be able to occasionally cast a low level spell.. .. if magnitudes were just worked out linearly, everyone would need a casting total of 50 in their arts just to spont making a candle light for sun duration