Omniscience and tax effects

[Telperion]

The oracle on Omniscience reads:

You may cast nonland cards from your hand without paying their mana costs.

Additional rulings on Gatherer:

7/1/2012 You must follow the normal timing restrictions of each nonland card you cast.
7/1/2012 If you cast a card "without paying its mana cost," you can't pay any alternative costs. You can pay additional costs such as kicker costs. If the card has mandatory additional costs, you must pay those.
7/1/2012 If the card has X in its mana cost, you must choose 0 as its value.

1. My question is how does omniscience affect the cost of your spells under the presence of the common "tax" cards. In my experience, the taxes usually win the fight and you are forced to satisfy them, but the wording "without paying" makes in seem kind of contradictory. I understand that if the cards states, "as an additional cost, sacrifice x" etc, but the following are kind of shady:
a. Thalia
b. Trinisphere

[Koby]

7/1/2012 If you cast a card "without paying its mana cost," you can't pay any alternative costs. You can pay additional costs such as kicker costs. If the card has mandatory additional costs, you must pay those.

You would be responsible for those additional taxing costs. Think of it like casting Force of Will with it's alt-cost under the same conditions.

[cdr]

"Without paying its mana cost" is an alternate cost. Mana cost is what's printed on the card. Total cost is what you pay when you play the spell, which is not the mana cost.

Cost/alternate cost + additional costs - cost reductions + minimum cost (Trinishpere) = total cost.

[TerribleTim68]

...Cost/alternate cost + additional costs - cost reductions + minimum cost (Trinishpere) = total cost.

Or - λf·(λx·f(x x))(λx·f(x x))
:wink:

[dahcmai]

On the same subject, how does this interact with X spells such as Stroke of Genius?

For example what is the total cost paid if you have Omniscience out, Thalia, and want to draw 2. Can that even be done or do you have to pay the normal cost?

[cdr]

On the same subject, how does this interact with X spells such as Stroke of Genius?

For example what is the total cost paid if you have Omniscience out, Thalia, and want to draw 2. Can that even be done or do you have to pay the normal cost?

The only valid choice for X when you're not paying a mana cost is 0, so you can't cast it with Omniscience and draw cards. You can choose to pay mana and cast it for at total cost of 2U+2+1 though, sure.

One tricky thing you can do with total cost though is, say, announce X=2 when you only have mana for 1 and then use a cost reducer to still play it.

[Mr. Ages]

Same situation above, but along with Trinisphere, I have a Lodestone Golem.

Omniscience makes the spell 0.
Lodestone makes it 1.
Trinishpere makes it 3.

Cost is 3

Correct?

[Koby]

Correct?

Yes.

[drude1]

Interesting. Most other threads say that Omniscience basically makes trinisphere worthless. How sure are you that trinisphere adds 3 to any "free" spell with omniscience? Thanks.

[menace13]

Interesting. Most other threads say that Omniscience basically makes trinisphere worthless. How sure are you that trinisphere adds 3 to any "free" spell with omniscience? Thanks.

Same as when youre casting Force under 3spehre

[Esper3k]

Trinisphere is always the last thing checked in determining how much mana a spell costs to play, so things that make spells free or cost 0 still get boosted up to a minimum of 3 mana cost by Trinisphere.

[Julian23]

Trinisphere always wins. Where did you get such crappy other advice on Omniscience/Trinisphere?

Another tricky thing is Engineered Explosives under Thalia, Guardian of Thraben. The additional mana that Thalia makes you pay actually counts towards Sunburst. So, if you want it on 1, announce it for 0 and pay the additional mana with any colored mana.

[ween]

Cost/alternate cost + additional costs - cost reductions + minimum cost (Trinishpere) = total cost.

Thanks for the clarification on this, great explanation.

[cdr]

Another tricky thing is Engineered Explosives under Thalia, Guardian of Thraben. The additional mana that Thalia makes you pay actually counts towards Sunburst. So, if you want it on 1, announce it for 0 and pay the additional mana with any colored mana.

This is because Sunburst checks the number of colors paid for the total cost. There's long been some tricky things done with cost increasers and sunburst, like putting more than 4 counters on Etched Oracle.

[jhhdk]

Trinisphere always wins. Where did you get such crappy other advice on Omniscience/Trinisphere?

Another tricky thing is Engineered Explosives under Thalia, Guardian of Thraben. The additional mana that Thalia makes you pay actually counts towards Sunburst. So, if you want it on 1, announce it for 0 and pay the additional mana with any colored mana.

Hmm, does that mean you can't play it with 0 counters if you only have colored mana?

[Esper3k]

Hmm, does that mean you can't play it with 0 counters if you only have colored mana?

If Thalia or some other cost increasing effect is in play, that's correct.

[drude1]

Another question, does Thalia have the same effect as Trinisphere? Thalia reads a little differently ("noncreature spells cost 1 more to cast") which suggests that it's adding 1 to the mana cost. I assume that it still works as Trinisphere would but just want to clarify. Thanks again.

[Esper3k]

Another question, does Thalia have the same effect as Trinisphere? Thalia reads a little differently ("noncreature spells cost 1 more to cast") which suggests that it's adding 1 to the mana cost. I assume that it still works as Trinisphere would but just want to clarify. Thanks again.

Thalia (and other cost increasers like Sphere of Resistance, Thorn of Amythest, Lodestone Golem, etc) function similarly, but are different from Trinisphere.

As per the formula CDR posted above, cost increasers (Thalia, etc) are applied to the cost, then cost reducers (Affinity, for example) kick in, then last, Trinisphere looks at the final cost to see if it's 3 or more mana.

[Offler]

Sorry for digging out this thread but:

Dream Halls

Types:
Enchantment
Card Text:
Rather than pay the mana cost for a spell, its controller may discard a card that shares a color with that spell.

10/4/2004 This only replaces the mana cost (the mana in the upper right hand corner of the card). It will not pay additional costs from the card text (such as Buyback) or from other effects. It does not prevent you from paying those additional costs if you want or need to.

I believe that those cards work in the manner of tax effects exactly same. If there are some additional costs they must be paid and also X is zero.

The question is regarding commander rules. If the commander died once and is going to be cast from command zone - Can I discard a card, pay 2 colorless and cast him?

Also same question about Trinisphere. I believe that if i cast spell using Dream halls, and the cost of card which i am playing is 3 or more, no additional mana is needed.

[cdr]

The question is regarding commander rules. If the commander died once and is going to be cast from command zone - Can I discard a card, pay 2 colorless and cast him?

You can use Dream Halls instead of paying the mana cost and then pay additional costs, yes. The Commander rules (http://mtgcommander.net/rules.php) let you cast the commander from the command zone and paying 2 for each time a commander has previously been cast from the command zone is an additional cost.


Also same question about Trinisphere. I believe that if i cast spell using Dream halls, and the cost of card which i am playing is 3 or more, no additional mana is needed.

As noted above several times, minimum costs are applied after cost reducers and increasers. If you're paying at least 3 in additional costs, Trinisphere will not add to the total cost.