short and sweet.
if i consider the "mental equivalent" to somehow be a representative a personal values in behaviour or just in thought processes, it actually makes logical sense (except for the part about influencing health, where only self-generated issues would make logical sense to be affected...but, yes, you can make yourself move sensitive to your environment through self-suggestion, and become a victim of, for example, your stress hormones, the rheumatism example from the book could work here).
what i did not like was the idea that you should ignore the negatives, it was not clear, but i think it did not mean ignore the negatives in "The Secret" style (blind manifestation no matter what), but try to change your mind about how they affect you, while also trying to fix any potential real issues.
like this, the speech can work, logically, even if you remove the religious elements (specific religious details, like what the soul is, or the Trinity, etc, in case those would make you feel a bit uncomfortable).
i really liked the behavioural therapy aspect of it.
...if this was meant as a manifestation manifesto though, i would not be able to support it. it's not a thing i, personally, choose to like.