why is this always 'no'?

They are all empty.

$post_array->elimination_of_uncertainty
$post_array->technological_in_nature
$post_array->permitted_purpose
$post_array->process_of_experimentation

empty is a technical term in PHP.
See https://www.php.net/empty

---

Yes, that worked. I used
$post_array->elimination_of_uncertainty!=''
instead.

thx

proof that an old dog can learn new tricks