true

true => a & b

expect (a)
expect (b)

---

theory (a human weighs between 80 and 400 pounds) {
  $x is a human
    & $x weighs $y pounds
    => $y >= 80 & $y <= 400
}
  
$x says (i weigh $y pounds)
  => $x weighs $y pounds

$x says (my weight is $y pounds)
  => $x weighs $y pounds
  
john is a human
john weighs x pounds

expect (x >= 80)
expect (x <= 400)