> you either have something to channel or don't

Again, any evidence? What exactly is 'cognitive ability'? A hallmark of the lack of substantive argument is vague terms that can mean anything the speaker likes, and by not defining the term they prevent any substantive critique - nobody really knows what they're talking about (and usually, not the speaker either).

I highly doubt it's all or nothing. While there are likely variations in anything, they can be quite insignificant. For example, everyone, with tiny exceptions, can learn to speak & understand language, and write & read - highly sophisticated cognitive abilities. And they can improve those abilities through education.

These baseless generalities don't show much 'cognitive ability'.