no it doesn't work, there's a FAQ that expressly denies it. You only have two hands worth of effort. So since your earthbreaker used two hands, you have no hands left over to Two-Weapon Fight with.
Yes, the faq - a fairly controversial one since it's based on unwritten rules that are undiscoverable in the written rules and unknown even by a few Paizo writers.
That said, consult your GM and discuss the issue. Two-weapon fighting's own structure should reasonably handle it and keep the option from being too powerful if you decide to ignore the faq.
Two weapon fighting references a "primary" hand and an "off-hand". Those are the 2 different hands of effort. If both hands of effort are being used to hold a two handed weapon, then you have no "hands" left to attack with a second weapon.
"a fairly controversial one"..."based on unwritten rules"..."undiscoverable in the written rules"..."unknown even by a few Paizo writers"Not biased at all, are ya? ;)
Is anything in what he wrote false?
It's okay to be biased as long as you're correct. Often times attempting to not be biased can get you to ignore the facts, like CNN and its relentless attempts to appear non-partisan no matter how crazy one side of the table gets.
Yes, the faq - a fairly controversial one since it's based on unwritten rules that are undiscoverable in the written rules and unknown even by a few Paizo writers.
That said, consult your GM and discuss the issue. Two-weapon fighting's own structure should reasonably handle it and keep the option from being too powerful if you decide to ignore the faq.
Aside from being strictly better than normal two-weapon fighting as most folks envision, even if you're twirling a two-bladed sword to get it. (And then, can Spinny Chopsword there use her armour spikes to get a third attack in?)
The two-handed weapon + armor spikes got nixed. Anyway, IIRC the ruling was more to prevent things like using TWF with a two-handed weapon and "off hand" unarmed strikes (kicks), considering all of the ways to boost unarmed strike damage, than just armor spikes.
However, a Toothy half-orc or a Maw or Claw (Maw) tiefling (or even a raging barbarian with the Animal Fury rage power) can still get in a bite as a secondary natural attack... without penalizing the attacks with the two-handed weapon (granted, the bite is at -5). If you are willing to dip two levels in ranger (Natural Weapon combat style to pick up Aspect of the Beast (Claws of the Beast)) and spend a feat on Multiattack (if the GM lets you take it), then you can get the bite at -2 while the two-handed weapon is still without a penalty.
Armor spikes do not allow an extra attack if already TWFing with a weapon in each hand (or a double weapon), but you can get a third attack when TWFing with a bite: weapon/weapon/bite at penalties of (assuming TWF feat and light off hand or double weapon) -2/-2/-5. There's a reason half-orcs are a popular choice for rangers (Toothy, plus orc double axe as a martial weapon), even without going the Aspect of the Beast/Multiattack route.
What he can do is grab a one handed weapon (such as a warhammer) and then just take a hand off of it while doing TWF.
I generally like this kind of style for rangers (who can str TWF, so they love 2 handing). I go more for a cestus than armor spikes, but same general idea.
Not quite as good as using a double weapon (since weapon focus is not friendly with this) but it has other advantages (such as better crit range on your weapons than most free double weapons)