This is how we do science today and is why I put my trust in the advances that have been made in science.
But it is often still claimed that the modern scientific method was not established until the early 17th Century by Francis Bacon and Rene Descartes.
There is no doubt in my mind, however, that Ibn al-Haytham arrived there first.
With all due respect to the article's author and his enthusiasm for science and history, this seems like typical dead white male bashing. So we've ascertained that many centuries before Descartes and Bacon an Arab scientist developed what we now call the scientific method. That's interesting for historical reasons. For scientific purposes, however, that's irrelevant unless Bacon, Descartes or Newton had read his work. Was Ibn al-Haytham available to them? The article doesn't clarify that. Most likely these European scientists arrived at the same findings independently, and that's important to take into consideration.
History concerns itself with chronology, order, A to Z. But science, and the arts and philosophy for that matter, are about who influenced who, not who discovered what first. As a student of literature I know that Tolstoy invented the stream consciousness before James Joyce, but I also know stream of consciousness is universally used today because of Joyce's influence on 20th century literature.
So unless someone proves that Newton, Bacon and Descartes were aware of Ibn al-Haytham, he will be nothing but an historical anecdote, a new footnote to add in future updated histories of Western science, and not the giant whose shoulders Newton sat on.