Can a Trickery Cleric cast spells through their duplicate when the Cleric would normally be unable to cast spells?

Question

Inspired by this question, can a Trickery Domain Cleric get around effects that would normally prevent the Cleric from casting if they move their Invoked Duplicate outside of the effect?

As a concrete example; the Cleric (Bob) gets into a battle with another spell caster (Daryl). Daryl wants to keep Bob at bay and casts Silence trapping Bob in a soundproof area. Daryl invokes his duplicate (no sound required) and has the duplicate run out of the range of the Silence spell to attack Daryl.

So with Bob in the radius of a Silence spell, can he cast spells via his duplicate that is outside of the spell effect?

Per the spell description:

For the duration, you can cast spells as though you were in the illusion's space, but you must use your own senses.

So Bob casts as if he was in the illusion's space, not effected by Silence. And "talking" isn't a "sense" like vision or hearing. So that should not be an issue.

Can Bob hit Daryl with an Inflict Wounds to try and break Daryl's concentration and lower the Silence spell?

Answer 1

In your specific scenario, yes. But in other situations, maybe not

The Invoke Duplicity option for Trickery Clerics reads:

[...] you create a perfect illusion of yourself that lasts for 1 minute, or until you lose your concentration (as if you were concentrating on a spell). The illusion appears in an unoccupied space that you can see within 30 feet of you.

[...] For the duration, you can cast spells as though you were in the illusion's space, but you must use your own senses.

Because the description says "you can cast spells as though you were in the illusion's space," Bob would not be subject to the effect of silence because, as you say, the illusion is not within silence's area of effect and it does not impact Bob's senses in a way that prevents spellcasting otherwise.

In other situations, Bob might still not be able to cast a spell through the illusion in this manner. For example, if Bob were bound in some way that prevented him from providing the somatic/material components of a spell.

Simply being in the illusion's space does not mean Bob the cleric is relieved of being bound.

Likewise, if, say, an area of magical darkness were to be summoned on Bob after the illusion were summoned (it would have to be after because Bob wouldn't be able to see a space to summon it in the first place), then Bob would not be able to cast a spell that required him to see to target even if the illusion is in a space that is outside of the area of darkness. This is because his own senses are still impacted by the darkness.

Another factor: spells need a clear path to the target (unless they say they don't). It could be that the illusion is in a space that is unaffected by the AoE but does not have a clear path to the target.

The spell inflict wounds is a touch attack, which Trickery Clerics are allowed to use in conjunction with Invoke Duplicity's illusion. So as long as the illusion can get within reach, Bob can use inflict wounds on Daryl through the illusion.