I used to do a lot of PHP, and I love Clojure (all my work for the past year has been Clojure only), so I totally get where the author is coming from. Comparing Clojure and PHP is not even fair, whether we're talking performance, concurrency, or elegance.
In the process of learning Clojure, I have discovered a "better" way to write PHP:
1. Use PHP namespaces (5.3+)
2. Use functions in those namespaces that take mostly PHP arrays and sometimes other params, modify them, and return new/modified arrays and params (again, that's similar to how data flows in Clojure, albeit not "pure")
3. Minimize or eliminate use of classes, objects, public, private, protected, getters, setters, and other OOP goofiness; classes with static properties/methods are OK
I tend to have quite a lot of objects that are basically what I'd use complex closures for in a lispy language - i.e. a bunch of read only attributes, then some methods that use those as configuration/etc.
That's basically a 'bigger hammer' version of (2) though - mutable state is, as ever, the enemy.
In the process of learning Clojure, I have discovered a "better" way to write PHP:
1. Use PHP namespaces (5.3+)
2. Use functions in those namespaces that take mostly PHP arrays and sometimes other params, modify them, and return new/modified arrays and params (again, that's similar to how data flows in Clojure, albeit not "pure")
3. Minimize or eliminate use of classes, objects, public, private, protected, getters, setters, and other OOP goofiness; classes with static properties/methods are OK