Rationalizations about Ur Priest enached spellcasting

[Conradine]

I was wondering about why Ur Priests are able to gain new spell levels twice as quickly as both Mage and Clerics. After all, no one can study more than a passionate Mage and no one is more devout than a zealous Cleric.

So, here's my rationalization.

Ur Priests skip the prerequisites for harvesting powers, so they find it easier.

Basically, a mage needs to turn unrefined magic into refined magic through complex visualization and meditation exercises, then use it ( source: Tome of Magic )
A cleric gets refined, ready to use magic from his god or abstract source, but he must draw this power through direct effort, by willpower and faith.

So, I guess that an Ur Priest needs not to refine magic nor to draw this power from his source. He just stole the finished product, so he can do it more easily.


Any other idea?

[Flickerdart]

Ur-priests are not the only fast-progression casting class, far from it. The Apostle of Peace and Divine Crusader also have accelerated progressions.

[Florian]

Any other idea?

Ur-Priests realized that there´s a disconnect between "Divinity" and "Deities" and learned to use that to gain power.

The followers of more traditional routes gain their power more slowly, but are more firmly set in wielding that power, meaning way more slots/day and domain slots.

[Willie the Duck]

The entire concept of the ur priest is that they are "cheating." They are gaming the gods, stealing power, and otherwise breaking the normal rules. It's not surprising that they get a quicker payout.

[Janthkin]

Ur-Priests are stronger willed (and more experienced) than 1st level characters - they have a better feel for their own limits, and no arbitrary divine external limitations to slow them down.

[Jack_Simth]

Ur-priests are not the only fast-progression casting class, far from it. The Apostle of Peace and Divine Crusader also have accelerated progressions.
Yes & no.

Yes, there are other PrCs that grant casting faster than one spell level per two class levels.
However: Most of those have entry level requirements that (without early entry techniques) prevent getting into the class early enough to get higher level spells than a pure-classed Cleric or Wizard except at maybe one level towards the end, or are very bad in general. I'll start with your named examples:

Apostle of Peace: Book of Exalted Deeds: Requires 10 ranks in Concentration. A Monk taking the class has:
1st level spells at character level 8
2nd level spells at character level 9 (if wis 14 or better).
3rd level spells at character level 10 (if wis 16 or better).
4th level spells at character level 11 (if wis 18 or better).
5th level spells at character level 12 (if wis 20 or better).
6th level spells at character level 13 (if wis 22 or better).
7th level spells at character level 14 (if wis 24 or better).
8th level spells at character level 15 (if wis 26 or better).
9th level spells at character level 16 (if wis 28 or better). This is the only level at which the Apostle of Peace is ahead of a cleric in terms of highest level spell available.
9th level spells at character level 17.

Divine Crusader: Complete Divine: Requires BAB+7. A Paladin-7 taking the class has:
1st level spells at character level 8 (if cha 12 or better).
2nd level spells at character level 9 (if cha 14 or better).
3rd level spells at character level 10 (if cha 16 or better).
4th level spells at character level 11 (if cha 18 or better).
5th level spells at character level 12 (if cha 20 or better).
6th level spells at character level 13 (if cha 22 or better).
7th level spells at character level 14 (if cha 24 or better).
8th level spells at character level 15 (if cha 26 or better).
9th level spells at character level 16 (if cha 28 or better). This is the only level at which the Divine Crusader is ahead of a cleric in terms of highest level spell available.
9th level spells at character level 17.

Compare to Ur-Priest. An Ex-Cleric of Trickery (or a multiclass of base classes in the PHB - bard, plus a single level of fighter will do) can meet all requirements at 5th, to take the first level at 6th. In that instance, the Ur-Priest has:
1st level spells at character level 6
2nd level spells at character level 7 (if wis 14 or better).
3rd level spells at character level 8 (if wis 16 or better).
4th level spells at character level 9 (if wis 18 or better).
5th level spells at character level 10 (if wis 20 or better).
6th level spells at character level 11 (at this point and beyond, Siphon Spell Power reduces the Wisdom requirement).
7th level spells at character level 12. AHEAD OF CLERIC
8th level spells at character level 13. AHEAD OF CLERIC
9th level spells at character level 14. AHEAD OF CLERIC
9th level spells at character level 15. AHEAD OF CLERIC
9th level spells at character level 16. AHEAD OF CLERIC
9th level spells at character level 17.

You also have the Blighter from Complete Divine (qualify as an Ex-druid 6), which is ahead of the cleric in terms of highest level spell available from character levels 14, 15, and 16 with a high enough wisdom, but the spell list is just terrible without expending other resources on increasing the spells on it.

[Flickerdart]

Yes & no.
You will notice I said fastest progressing and not earliest access to spell levels. The classes I mentioned, as well as ur-priest, progress spells faster than wizard and cleric levels. What the character does before those class levels is not relevant, and arguing otherwise is akin to arguing that the turtle is faster than the hare.

[Jack_Simth]

You will notice I said fastest progressing and not earliest access to spell levels. The classes I mentioned, as well as ur-priest, progress spells faster than wizard and cleric levels. What the character does before those class levels is not relevant, and arguing otherwise is akin to arguing that the turtle is faster than the hare.
Depending on your purposes, that's actually a valid argument.

Consider a person planning a trip across a state (300 miles), weighing two options.

He can hop in his car, get on the freeway, and drive for five hours at 60 mph on a little-used stretch of freeway to get that 300 miles in.
He can go to the airport, get on a plane, and fly at 300 mph for an hour to get that 300 miles in.

The airplane travels faster. However: The traveler is more likely interested in the time taken than absolute speed.

If it takes half of an hour to get to the airport, three hours to get through the various checkpoints and lines, one hour of the actual flight, 30 minutes to collect his luggage and pick up the rental vehicle, then another 30 minutes to get from the airport to his actual destination vs. one minute to drive to the freeway on-ramp, five hours of driving, and one minute to get from the freeway off-ramp to the actual destination... driving takes 5 hours 2 minutes, while the flight takes 5 hours 30 minutes. If you're interested primarily in total time, the drive "wins the race" relative to the flight, even though it can't go as fast.

Likewise, if you're comparing mechanical advantages and disadvantages for a character, If you're starting at level X, and plan to play to level Y, a breakdown of what level range build A is stronger than build B is extremely relevant. You probably wouldn't want to play a 1-10 campaign with a build plan that's close to useless until level 12, for instance.

Your post was completely factual. For people not familiar with the referenced classes, however, it's likely to be misleading, as the difference between "faster progression" or "accelerated progression" and "better access than the standard full casters" will be lost on a lot of people without further background.

[Flickerdart]

The airplane travels faster. However: The traveler is more likely interested in the time taken than absolute speed.
What the traveller is interested in doesn't matter even a little bit when there is an existing discussion about absolute speed, of which the traveller is not part.

[Willie the Duck]

Okay, so we are violently agreeing on the facts of the matter and only disagreeing on what is important. I don't think one viewpoint can be called more relevant to the discussion at hand than the other, since it isn't clear from the OP what is on topic except for 'other ideas' to justify how an Ur Priest rapidly rises in spell power.

Myself, I don't see why there is an issue. An Ur Priest is a very specific concept (unlike some PrCs, which are very much "why does this exist?") that invites its own special rules. It is a fun class, and not one I consider overpowered unless you pull some kind of Ur-priest/Sublime Chord theurge cheese, and even then it is usually a lot of investment for a payoff that only happens (or at least exceeds everyone else) in the last level or two.