What do you call to a person who places dogmatic faith in the methods of science?
What is the agent noun (eg biologist for biology) corresponding to scientism? Here scientist would be confusing.
I'm looking for what I intuitively want to call "scientist", but that means the opposite of what I'm looking for.
Though scientist is obviously the correct word, I doubt that's what you're looking for. Depending on the context, I occasionally use "empiricist", "positivist", "rationalist", or even (sadly) "verificationist" when I get tired of using "scientist."
What term refers to those who adhere to scientism?
To first clarify the question, "scientism" is the belief that the only valid way to understand the world is through application of the scientific method.
A scientist is a person who uses the scientific method to understand the world; a scientist need not believe that the scientific method is the only valid way to understand the world. And a believer in scientism need not actually practice science. So scientist is out.
Someone who is alleged to believe in scientism is, unfortunatly, said to be a scientismist, which is a terribly inelegant word. You might consider whether empiricist or logical positivist work in your context. I note also that an accusation of scientism is frequently pejorative in a way that an accusation of empiricism is not.
There doesn't seem to be a word in English that captures the sense that you are looking for.
One who uses the methods of science is called
a scientist.
One who places dogmatic faith in a system might be called
a dogmatist or dogmatic
Methods of science are usually synonymous with rationality, which includes the avoidance of dogma. But that doesn't preclude people from acting dogmatic about whatever belief system they have. Dogma means a set of rules that you must follow. The methods of science are methods that were found through experimentation and comparison with a common reality; some may learn those methods as rules and follow them dogmatically.
'Scientism' sounds to me like a variant of theosophy, Christian Science, or even scientology, and doesn't associate with dogmatic support of scientific methods.
So a single word doesn't work, but there are multi-word phrases or neologisms that might work:
dogmatic scientist, hyperrealist, hyperrational.
all of which give a negative light to the scientific part which is what you are looking for.
Perhaps the word needed is 'Cartesian' following Descartes. Another word is 'rationalism'. But we are on the edge of a vast philosophical debate here. If you are going to describe this person in the way you do, as 'one who puts their faith in the methods of science', you need to be more specific. As opposed to faith in what else? There are a multitude of philosophers, mostly of the Enlightenment period, who would approach the subject in different ways. I'm no expert, but I don't think the mere term 'scientism' would be accepted as having much descriptive validity among authorities on such figures as Kant, Descartes,Hume, and others. In short it is perhaps the type of question that could only be answered by taking an undergraduate degree in philosophy. Having said all that there does appear to be a comprehensive Wiki article on 'scientism' which may be worth reading.
scientismist SCI-EN-TISM-IST = Adherent of Scientism (Religion refuted by Science). Not to be confused with Mary Baker Eddy's CHRISTIAN SCIENCE or L. Ron Hubbard's SCIENTOLOGY. Scientismists are usually atheists or agnostics. Sometimes they are members of mainstream religious groups, but, with God and Scriptural stories being only symbolical, but not literal. Scientism is the view that the natural sciences are the only source of genuine knowledge and, in particular, that they alone can yield true knowledge about man and society, employing the reduction of all knowledge to only that which is measurable.
In the absence of a conventional noun form, I would propose using the accepted adjectival form as a substantive: scientistic.
If the scientistic had saints, J. Evans Pritchard would be the patron of poetry.
Catholics are another example of adherents to an -ism not known as -ist s, even though Catholicist is not in common usage, and when discussing the intellectual movement of Romanticism, Romantic is accepted alongside Romanticist. The same applies for many movements named after people: we have Aristotelians, not Aristoteleanists, though the school is Aristotelianism.
Otherwise, as others have suggested, one would need to adopt another word as a synonym, hyperempiricist or whatnot.
