Cross Class Spells

[DireSickFish]

So my friend has a rather obsurd multi class build and it got us talking about how cross class spells work. He is claiming that as a lvl6bard/lvl2warlock/lvl2pally/lvl4sorc he can use his college of lore ability to gain 4thlvl+ spells because those are spell slots he can cast. I'm contending that because as a bard he only has access to 3rd lvl sspellsthat they have to be 3rd or lower.

As an example I said that a 16th lvl wizard taking his next level of cleric could not prepare a 9yh lvl cleric spell and he contends that you can by RAW. What is the correct way to deal with cross class spellcasters by RAW? Has mearls or anyone offers clarification? Is the bard ability different than normal cross classing rules?

[calebrus]

I'm contending that because as a bard he only has access to 3rd lvl spells that they have to be 3rd or lower.

You are correct.
The multiclassing rules state that each class knows and/or prepares spells individually, as if you were a single classed member of that class.
So when learning bard spells, he is a lvl6bard/lvl2warlock/lvl2pally/lvl4sorc
So when learning warlock spells, he is a lvl6bard/lvl2warlock/lvl2pally/lvl4sorc
So when learning pally spells, he is a lvl6bard/lvl2warlock/lvl2pally/lvl4sorc
So when learning sorc spells, he is a lvl6bard/lvl2warlock/lvl2pally/lvl4sorc
just like a single classed character at that level would be able to.

None of the other levels matter. You are single classed for the purposes of spells known and prepared.
As none of the other levels matter, none of the benefits of those levels matter, and that means none of the spell slots gained from those levels matter.
He's looking at total slots. But that means he isn't treating himself as single classed. He's reading it incorrectly.

[pwykersotz]

By RAW it's spelled out on pages 163 and 164 of the PHB. Use the example paragraph in the bottom right of the page under Spell Slots for a very similar, though simpler, build.