I can't believe this discussion is going again... We hashed this out on the wizards forums for over 30 pages!
You make it sound like we came to a consensus after 30 pages....we certainly did not!
1. Instantaneous duration on spells is clearly stated in the PHB description of what the word means as being a spell that is cast and resolves within a single turn. It also cannot be DISPELLED specifically because of that reason. It NEVER says anything about the spell having all of its attacks (if any) be simultaneous, require targets to be selected before a single attack is made and whatever other things some people in this thread have brought up.
The bit you quoted is true, but in no way changes what 'instantaneous' means. These are notes on the consequences of a spell being instantaneous: it cannot be dispelled
because the energy has already come and gone, so there is no magic to dispel. This in no way means that instantaneous spells last for ages but are somehow immune to
dispel magic.
2. The only spell in the ENTIRE GAME that has all of its attacks resolve simultaneously is Magic Missile.
It might be the only one with the redundant language, but that does not limit the meaning of the 'instantaneous' duration.
The only reason why it works that way is because the spell itself specifically says that it works this way.
Even without that redundant language, the spell's instantaneous duration means that it works that way.
The general rules, found on pages listed previously in this thread (notably by [MENTION=6780410]spectacle[/MENTION] who actually quoted the text itself), explain that for each attack made the attacker must follow 3 steps. The first step is picking a target. This is true for ANY attack being made in 5e!
Agreed. Every attack must take those steps in order.
So no, you don't pick your targets immediately when casting the spell, you pick them when you make an attack.
And you make the attacks simultaneously.
Eldritch Blast can have several attacks, just like someone with the Extra Attack feature using the Attack Action. Both of these would follow the Making an Attack section as follows:
Attack 1
Pick a target
Determine Modifiers
Resolve the Attack
Attack 2
Pick a target
Determine Modifiers
Resolve the Attack
And so on until the attacker has no attacks left.
And the following sequence also obeys the rules on Making An Attack:-
Pick targets for bolts 1, 2 and 3
Determine the modifiers for each attack
Resolve each attack simultaneously
Note that the Attack action has certain rules that apply to attacks made using that action, but the Cast A Spell action doesn't have all the same rules. There is no rule that allows you to move between attacks granted by the Cast A Spell Action, for example, only to the attacks granted by the Attack action.
3. Mike Mearls has publicly stated that he is not the guy to ask about rules. He has been found to be wrong about his answers over 50% of the time and most notably, Jeremy Crawford has had to recheck and give the correct answers.
But this is not one of those times.
4. Eldritch Blast pushing a target 10 feet when it hits is simply to understand.
...and simple to
misunderstand...
You can only hit or miss with EB when you make an attack and each attack is a sequential event as shown above by the rules.
Mis-applying the rules for the Attack action and applying them to the Cast A Spell action...The rules do not support this.
Every time EB hits, you push 10 feet. Jeremy Crawford has also confirmed this via twitter and sage advice.
AFAIK, he has only said that a beam may push the target beyond the range of
subsequent beams...but beams from the same spell are not
subsequent, but
simultaneous.
The evocation does not limit you to once per use of the spell, every hit qualifies. Multiple attacks = multiple hits = multiple triggers. This is the same for ANY ability, feature, spell, etc.. that might have a specific trigger. Unless specifically stated, if you meet the trigger requirement multiple times you get the effect multiple times.
Abilities do what they say they do. Repelling Blast says that if a creature is hit with
eldritch blast, it can be pushed 10 feet. It does
not say that it pushes 10 feet for every bolt of the spell that hits, only that if it is hit by the spell.
An extrapolation of the rules that adds text to the rules can't be considered rules text.
A proper understanding of what words like 'instantaneous' means is essential when reading a rules set which proudly uses 'natural language' to convey those rules. Words have meanings. The writers expect us to know what it means, without having to define words which are used the same way in the rules as they are in real life. They have to tell us what a 'combat round' is because that's a game construct that is not found in real life, but 'instantaneous' is used the same way in the game as it is in real life, so does not need to be defined by the rules.
When we understand what 'instantaneous' means, we are not 'adding to the rules' because the rules already take the meaning of the word into account.