Don't forget, it has been made to look as if it dates beyond last Thursday ;)
When you think about it, if our brains are but chemical reactions produced by natural processes outside of intelligent design, who is to say for sure such a claim is not TRUE?!
As opposed to what? Ectoplasmic or spiritual reactions?
But even if we were intelligently designed and our minds are not "only" processes in a material brain (but processes in some kind of supernatural entity) we cannot say whether this designer isn't also the product of an even higher intelligent entity (e.g. super[2]natural) and so on? In other words it's Turtles all the way up.
And that's exactly what Occams Razor is about. If there is no way to tell whether [A] or NOT[A] is true, NOT[A] is assumed unless we find compelling evidence for [A].
...and so on?.
On the face of it I treat it as an interesting philosophical proposal but I do not sense it matches objective reality. But on what basis apart from what I have been taught? A *real* skeptic would say everything we know about ourselves and the universe is but a figment of the imagination. Can you disprove that claim?
I tend to walk a fine line between reason and unreason, as you can probably tell.