I neglected to include the Latin that comes after that phrase:
Why does Epicurus say it's not necessary to argue about this? I take this to mean "this is discernible to the senses." It's self-evident. It's like discussing if fire is hot. Duh!
I find parallels in all this in the natural, necessary discussion. The necessary desires should not, according to Epicurus, require a lot of labor to procure. If they do, maybe they're not necessary. Same thing with his saying, it's not necessary for me to try and convince you. If you can't see this, you're just not looking. I shouldn't have to work at concocting convoluted arguments to make you see pleasure is the Chief Good when it's as plain to see as fire is hot.