Not at all. A strong subjective opinion is often of debatable value. An asinine one is simply useless. You can have a subjective stance on many issues, or definitions. If it isn't one supported by logic, good reasons, or otherwise backed up it's a poor stance to hold. Like this one. let A be the set of all activities that are not multitaskable let B be the set of things that are "real work" A = {∅,construction,sleeping,...} His logic is: ∀x(x ∈ A ↔ x ∈ B) Anyways I think the distinction is useful personally. I also think your just a bit bootyhurt about him using the term "real work". Though you could be trying to make this argument: ∀x(x ∈ A → x ∈ B) ∧ ∃x(x ∈ B ∧ x 6∈ A) 6∈ = not an element of and if this is what your saying tell me what you think needs to be added I'd write out what this means but since you've used the word logic a bunch of times now I'm sure you can figure it out for yourself :lol: Set B isnt definable since the definition is not clear, hence your full argument falls apart