Well the guy is wrong, we can't just believe it.

I can argue the metaphysics of 3rd or 3.5 edition D&D magic for aeons if you'd like. That was damn near the point of most of the sessions of a couple campaigns that I played in. We ended up deciding that a level 1 Cleric, level 1 Wizard, and a level 5 engineer would be a damn near unstoppable force because the Engineer could tell the Cleric where to use a Summon Water cantrip, and tell the Wizard what form to hold the water in using the Shape Water cantrip.

We also ended up discussing the ramifications of a spell that could turn your target into a black hole. Here's a hint, unless you have used at least the "Nailed to the Sky" Epic Spell, or what we developed, namely, "Nailed to the Star" as the first part of your spell, (this puts you in a stellarsynchronos orbit around the nearest star at a distance of 1,000,000 miles above the surface of the stars atmosphere. ≈2,000,000 KM.) you're going to blow yourself, and a significant portion of the world around you to smithereens. Nailed to the Star allows one to use the magic to transport every bit of even a God, Elder God, or Titan to a single place as long as that place isn't going to be a Prime Material for even the next turn, which they won't. In a Gods case, they, their soul, their avatars, their "phylactery," (aka magic items that could allow them to be resurrected) and anything else that could have ever been part of that being, are instantaneously teleported into a dimensional anchor. That dimensional anchor prevents magical or psionic beings from leaving with any teleport or plane shift like ability. As soon as ALL of the target has been shifted into a place that is almost guaranteed to be empty space, a wall of force that is spherical and 1,000 miles in diameter forms, and instantly collapses everything in it down below the Schwartzchild radius, creating a black hole that will explode in less than a second.

Needless to say, we ended that campaign with our party deciding who the next pantheon would be.