Cabal Therapy with Trinisphere

[nastiupset]

Long time lurker here. I was playing on xmage the other day and I have a Trinisphere in play. My opponent has Academy Rector in play, no free mana and Cabal Therapy in the graveyard. He is able to flash back Cabal Therapy and sacrifice the Rector without paying any mana. Cabal Therapy did not resolve (ie, he neither named a card nor looked at my hand), but the damage was done: he got to search for some monster enchantment and put it into play. I don't recall what the xmage message window reported during this.

Is this a bug or the correct sequence of actions?

[kombatkiwi]

Long time lurker here. I was playing on xmage the other day and I have a Trinisphere in play. My opponent has Academy Rector in play, no free mana and Cabal Therapy in the graveyard. He is able to flash back Cabal Therapy and sacrifice the Rector without paying any mana. Cabal Therapy did not resolve (ie, he neither named a card nor looked at my hand), but the damage was done: he got to search for some monster enchantment and put it into play. I don't recall what the xmage message window reported during this.

Is this a bug or the correct sequence of actions?

This is a bug, you can't attempt to cast something unless you can pay all of the costs.

[cdr]

This is a bug, you can't attempt to cast something unless you can pay all of the costs.

You can always attempt to cast a spell, but the game state is reverted to the point before you attempted to cast it if you cannot complete the actions required to cast it, such as paying all costs. Certain spells would be impossible to play otherwise.

https://yawgatog.com/resources/magic-rules/#R720

In the case of the Academy Rector, it's un-sacrificed and the ability never triggers.

[ParkerLewis]

Certain spells would be impossible to play otherwise.

Out of curiosity "and for science :)", could you share a few examples of what you mean ?

[cdr]

Out of curiosity "and for science :)", could you share a few examples of what you mean ?

The game can't "look forward" before you announce a spell to know whether you actually are capable of paying all costs, especially when choices during the announcement of the spell like modes, alternate costs, the order in which you activate mana abilities, or the order you pay costs can affect your ability to activate mana abilities or pay other costs.

If you had to have the ability to pay beforehand, it would be hard to announce Force of Will if you had no available mana sources but an extra blue card in hand, unless a special rule for alternate costs was added to the rules the way there's a special rule for announcing cards that have a mode or alternate cost that allows them to be cast as if they had flash.

Note that being able to attempt to cast something without knowing whether you can completely cast it is only from a game rules perspective; the tournament rules / IPG frown on knowingly attempting to do something you can't actually do, to put it lightly.

A very simple example of order mattering would be a Krark-Clan Ironworks, a Cursed Totem, and a Llanowar Elves. If you take the game state at the time of announcement for a 2G spell, can you pay for the spell? No, you can't.

[ParkerLewis]

Thanks. The alternate costs / FoW example is clear. (I'd argue the second one is less conclusive as an "impossibility" as you could elect to sacrifice the Totem before announcing the spell)

[cdr]

Thanks. The alternate costs / FoW example is clear. (I'd argue the second one is less conclusive as an "impossibility" as you could elect to sacrifice the Totem before announcing the spell)

It's meant to be a simple example. You can easily construct a similar situation for paying costs rather than activating mana abilities.