In the opening chapter, “0,” of his Scholastic Metaphysics. A Contemporary Introduction,* Edward Feser tells us (pp. 9-10) that

Of course, not every contemporary analytic philosopher welcomes the revival of old-fashioned metaphysics. There are those who decry it in the name of the scientistic or naturalistic position that science alone plausibly gives us objective knowledge, and that any metaphysics worthy of consideration can only be that which is implicit in science.

The second sentence of the passage offers what we may take as a definition of scientism, as the thesis or “position that science alone plausibly gives us objective knowledge.” It seems to me that Feser’s definition and others like it fail to respect an important distinction, one which I’ll identify and present here as that between scientism (tout court) and exclusivist scientism and which we can express in a quite concise manner by making use of the resources of the most elementary traditional logic. I do this not only because precision in the understanding of scientism tout court and of the various immediately opposed doctrines is important. I do it also because it illustrates the way in which the resources of elementary traditional logic can be put to use in precisely distinguishing between and among the members of other sets of immediately opposed doctrines.

Scientism (Tout Court) and the Immediately Opposed Doctrines Formulated

Feser presents another formulation of the doctrine, which he, Feser, identifies as scientism, that of Alex Rosenberg**:

[S]cientism faces a dilemma: it is either self-refuting or trivial. Take the first horn of the dilemma. The claim that “the methods of science are the only reliable ways to secure knowledge of anything” (Rosenberg 2011, p. 6) is not itself a scientific claim, not something that can be established using scientific methods.

A. Adopting and adapting the terms of Rosenberg’s statement, I’ll begin by identifying scientism (tout court) as the thesis, expressed by means of a particular affirmative categorical proposition, that:

(1.a.) At least some scientific methods of securing knowledge are effective methods of securing knowledge.

Then there is the thesis of universalist scientism, expressed by means of a universal affirmative categorical proposition, that:

(1.b.) All scientific methods of securing knowledge are effective methods of securing knowledge.

Universalist scientism is, of course, opposed by anti-universalist scientism, the thesis, expressed by means of a particular negative categorical proposition, that:

(1.c.) At least some scientific methods of securing knowledge are not effective methods of securing knowledge.

There is also the thesis of scientism, though anti-universalist (yes, I am struggling to come up with names both brief and telling), the thesis, expressed by means of the conjunction of a particular affirmative categorical proposition and a particular negative categorical proposition,  that:

(1.d.) At least some scientific methods of securing knowledge are effective methods of securing knowledge and at least some scientific methods of securing knowledge are not effective methods of securing knowledge.

The last to be presented of the categorical propositions having “scientific methods of securing knowledge” as their subject and “effective methods of securing knowledge” as their predicate is the thesis of anti-scientism, expressed by means of a universal negative categorical proposition, that:

(1.e.) No scientific methods of securing knowledge are effective methods of securing knowledge.

B. Turning now to some theses expressible by means of categorical propositions having “effective methods of securing knowledge” as their subject and “scientific methods of securing knowledge” as their predicate, we can first take note of another particular affirmative categorical proposition, the logically equivalent converse of (1) above, which can be taken as the defining thesis of scientism (tout court):

(1.f.) At least some effective methods of securing knowledge are scientific methods of securing knowledge.

The universal affirmative categorical proposition having “effective methods of securing knowledge” as its subject and “scientific methods of securing knowledge” as its predicate offers itself as the defining thesis of exclusivist scientism, that:

(1.g.i) All effective methods of securing knowledge are scientific methods of securing knowledge.

(1.g.i) is, that is, logically equivalent to:

(1.g.ii) Only scientific methods of securing knowledge are effective methods of securing knowledge.

And (1.g.ii) quite clearly gives adequate expression to Rosenberg’s statement of the doctrine which Feser identifies as scientism

We should not, however, conclude this section without taking note of the thesis of universalist and exclusivist scientism, that:

(1.h) All scientific methods of securing knowledge are effective methods of securing knowledge and only scientific methods of securing knowledge are effective methods of securing knowledge.

C. I think it safe to say that most us will accept as true and known at least such modest scientific theses as the following:

In at least some conditions, water boils at 100 °C. 

In at least some conditions, light travels at a finite velocity.

That is, we do adhere to scientism (tout court), even as we might not adhere to exclusivest scientism.

Similar Sets of Distinctions

The set of distinctions just put forth provides, as I indicated at the outset, an illustration of the way in which the resources of elementary traditional logic can be put to use in precisely distinguishing between and among immediately opposed doctrines. There is any number of sets of doctrines which can be similarly distinguished. I invite you to consider the set of doctrines the propositions expressing the defining theses of which can be generated by substituting “philosophic theories” for the “scientific theories” found in the propositions given above. Thus the doctrine, which I will with some regret dub as that of philosophism (tout court), expressed by means of a particular affirmative categorical proposition, that:

(2.a.) At least some philosophic methods of securing knowledge are effective methods of securing knowledge.

Etc.

Further still, there are the various doctrines the defining theses of which can be expressed by the sundry categorical propositions of which the subjects are “philosophic methods” and the predicates “scientific methods,” or vice versa. There is thus the doctrine, though not one which I would uphold, the defining thesis of which is expressed by the particular affirmative categorical proposition that:

(3.a.) At least some philosophic methods of securing knowledge are scientific methods of securing knowledge.

Etc.

Yet further still, I would like to nod in the direction of the diverse sets of syllogisms that call out to be explored. For here and now, it will be enough to present the relevant instance of the all-familiar “Barbara,” a syllogism in which all three propositions are universal affirmative categorical propositions.

All effective methods of securing knowledge are scientific methods of securing knowledge.                                                                                                                                            All philosophic methods of securing knowledge are effective methods of securing knowledge.                                                                                                                              Therefore, all philosophic methods of securing knowledge are scientific methods of securing knowledge

Etc.

Until next time.

* Edward Feser, Scholastic Metaphysics. A Contemporary Introduction (Neunkirchen-Seelscheid, Germany; Editiones Scholasticae, 2014)

** Alex Rosenberg, The Atheist’s Guide to Reality (New York: W. W. Norton and Company, 2011)