Incompatible Arts: Why no Corpus and Vim?

The Incompatible Arts virtue states that Corpus and Vim may not be picked with any Technique for this flaw. Why is this? I get that picking Creo Corpus and Creo Vim would block pretty important parts of lab work (longevity and vis extraction), but in the end it hurts the magus more than most other combinations - so why forbid it? I know I'm free to change it in my games as I see fit, I'm just trying to come up with reasons why it's not allowed RAW.

Serf's Parma - is it a minor flaw? If so, I'd argue that you just answered your own question: picking those two would be worth more than a minor flaw, and as such...you can't pick it as a minor flaw.

To protect players from committing obvious mistakes, that can be hard to undo in the middle of a campaign.

Cheers

It does seem silly that intellego aquam and intellego auram are allowed while perdo corpus and and muto vim aren't.

The first two seem like things that everyone can get along without while the second two seem like things that would often be useful but their loss would not cripple a character, in fact it very well might make a character more interesting to have to find other ways to do perdo corpus.

Agreed. Earlier editions permitted this (though I think in 4th they were worth more in the flaw).

I would agree about PeCo incompatibility making a good and flavorful Flaw. But - even long into a campaign - a SG can inadvertently trap a magus completely unable to suppress his sigil in his magic.
Anyway, a troupe always can allow - after some thought - further incompatible combinations, as Toa already noted in his OP. But once accepting an exceptional Flaw, the troupe better make sure it remains playable throughout the campaign.

Cheers

This is how I remember it as well. Something 5th ed omitted.
So with these explanations I hope the OP simply allows these combos as a Major Flaw then, if he want to explore this avenue

Well, I'm currently building an NPC with this flaw (a Tremere Dwarf with Incompatible Arts (Muto Corpus & Muto Animal) as well as Limited Magic Resistance (Corpus), who considers his body to be his greatest weakness and thus aims to make his mind his greatest weapon), and thus it's not much of a balancing issue in this regard.

One of my players made me aware that the Beast Master tradition from Houses of Hermes: Societates requires the flaw Incompatible Arts (Muto Corpus & Perdo Animal), so even published material comes into conflict with the base description of the flaw. Should this be errata'd?

I like to rationalise this as: all magi are born human, so all are very strongly linked to corpus. All Magi have The Gift, so are linked to the magic realm and strongly linked to Vim. These are best represented by Deficient Form than Incompatible Arts, everything else can be crippled in multiple ways.

By this logic, Mentem should be included as well. :wink:

Good Point. I think that only Creo Vim and Creo Corpus should be listed because that combinatios break two really different and independent Lab Totals that can be represented by others (Defficient Creo or Difficult Longevity Ritual) flaws. But, i am inclined to let take incompatible both with any others Techniques; really it's easy to imagine one healer with no way to harm living beings (PeCo and PeAn) or something like that.
Tru about the Defficient Forms.