Positivist vs. pragmatist verificationism

Previously, I discussed Ladyman and Ross’s criticism of pseudo-scientific metaphysics. They have in mind versions of contemporary analytic metaphysics that rhetorically emulate science, but fail to engage science in any meaningful way.

According to Ladyman and Ross, “taking naturalism seriously in metaphysics is equivalent to adopting a verificationist attitude towards both science and metaphysics” (1). If verification of hypotheses is a fundamental feature of scientific inquiry, then verification must be a fundamental feature of a naturalized metaphysics.

However, like all terms, “verificationism” has a history and Ladyman and Ross distinguish their adopted sense of the terms from other usages, specifically the Positivist usage.

We require some proper principle which distinguishes what we regard as useful from useless metaphysics. Note that in stating this as our aim, we immediately distance ourselves from the positivists and align our attitude more closely with that of Peirce and pragmatism. (2)

The basic difference

The Positivists used a criterion of meaning while Ladyman and Ross’s Pragmatist verificationism concerns epistemic value. The latter are not attempting to determine which language, or terms, are correct or legitimate to use in science, philosophy, or logic. Rather, Pragmatist verificationism attempts to index metaphysical claims to scientific claims in a way that provides them epistemological justification. For Ladyman and Ross, if the metaphysical claims are sufficiently naturalized, then they possess epistemic value.

Following Hilary Putnam’s 1995 “Pragmatism,” Ladyman and Ross distinguish their Pragmatist verificationism in three ways:

1. Positivist exclusion vs. Pragmatist application
2. Science as communal endeavor vs. science as individual endeavor
3. Evaluation of groups of scientific statements vs. evaluation of individual scientific statements

Exclusion vs. application

As I just mentioned, the Positivists employed their criterion of meaning to statements about the nature of reality in order to exclude illegitimate terms from use. Metaphysical objects and language bore the brunt of this assault. As Carnap put it:

The metaphysician tells us that empirical truth-conditions cannot be specified; if he asserts that nonetheless he ‘means’ something, we show that this is merely an allusion to associated words and feelings, which however, do not bestow a meaning. (3)

For Carnap, any claim about the nature of reality will be verifiable, at least in principle. One way of establishing a claim’s verifiability is to provide the empirical conditions under which the claim can be proven either truth or false. For the Positivists, metaphysical statements failed to provide such truth-conditions and therefore, were considered meaningless. Instead, these statements were taken to be about the nature of language or to express our feelings the world.

Alternatively, the Pragmatist attitude applies verificationism to metaphysics in order to distinguish good from bad metaphysics rather than exclude metaphysics altogether.

Recall that for Ladyman and Ross, metaphysics is a meta-scientific discipline that seeks to provide a unified picture of world based upon the details of scientific research. Since there is no scientific discipline which performs such a task, metaphysics provides this function, indexing its claims closely to those produced by contemporary scientific consensus. “Metaphysics…is the enterprise of critically elucidating consilience networks across the sciences” (4)

Ladyman and Ross’s naturalistic approach demands that they accept whatever entities scientific inquiry identifies (5). Their Pragmatist verificationism, which they articulate as the Principle of Naturalistic Closure, or PNC, is applied to metaphysical claims in order to ensure that they are made responsibly. If metaphysical statements fail the PNC, then they constitute bad, irresponsible, or pseudo-scientific metaphysics.

Communal endeavor vs. individual endeavor

Throughout history, philosophers analyzed science as a mode of thinking, one in which an individual engages. They introspected about their mental states and ideas as they practiced science, providing descriptions of their internal and external activities, as well as the relation between them. This procedure remained unchanged for hundreds of years until Peirce and Frege, separately, took an anti-psychologist approach to the evaluation of truth claims. The development of a new, more powerful logic allowed philosophers to analyze truth preservation through arguments without reference to internal, mental states. The age-old procedure was referred to as psychologism and was dismissed.

The new logical analysis of arguments was considered wholly mind independent. It was a system of terms and relations, the logically structure of which could be analyzed, without reference to the messiness of human thinking. Henceforth, the structure of science could be treated as an objective, communal object rather than the property of a specific mind. Consequently, the knowing subject transitioned from being the individual thinker to being the entire body of scientific practitioners. Science, and scientific knowing, was considered the task of a community rather than an individual mind.

The Positivists, inasmuch as their project began as an attempt to reduce the theoretical language of science to observation sentence, the content of which were claims about sense-data, followed the individual-endeavor model of science. Peirce, who’s model Ladyman and Ross follow, stated this in 1868: “We have no Power of Introspection, but all knowledge of the internal world is derived by hypothetical reasoning from our knowledge of external facts” (6)

Group evaluation vs. individual evaluation

Finally, Pragmatist verificationism is distinguished from the Positivist variety by the range of scientific statements to which it is applied. Positivist literature is replete with the logical analyses of the meaning of individual propositions. Pragmatist verificationism, however, follows Quine’s holism, which states that systems of beliefs, including science, succeed or fail as a system, rather than statement by statement. For the Pragmatist, the interdependence of scientific claims upon one another factors into metaphysical evaluation.

[W]e stress that what sound metaphysics should be connected with are substantial bodies of scientific results taken together, rather than individual claims taken one at a time. (Positivists, of course, discovered this second point themselves: this was the path that led through Carnap to Quine.) (7)

The Principle of Naturalistic Closure demands that any metaphysical hypothesis take at least two specific scientific claims, at least one of which comes from fundamental physics, into account. The collective consideration and evaluation of a metaphysical claim’s value is motivated by this holistic approach.

The cause of the difference

Ladyman and Ross reject any suggestion that there is an a priori, or independent, logical or rational structure regulating or limiting scientific practice, institutions, and norms. Relatedly, Quinean naturalism rejects any such attempt to justify science according to some standard external to science, an attitude with which Ladyman and Ross concur.

Our verifiability criterion has an essentially different status from that of classical and logical empiricists. The content of ours is settled by science, not by an a priori theory of the cognitive role of perception. Its purpose is to describe limits identified by scientists, not prescribe such limits. It is not part of the foundations of our view, but a consequence of the view’s application to the state of scientific knowledge. (8)

That the Positivists attempted to fit the scientific view of the world into their conception of its logical structure is, I think, uncontroversial. The abandonment of such a logical structure as something like a “first philosophy” of science is what characterizes the naturalism of Quine and of Ladyman and Ross. Philosophy of science is philosophy enough. 

The Positivists appeal to an independent standard external to science itself accounts for much of the difference in their verificationism from that of the Pragmatists, as well as their attitude towards metaphysics.

***

While this post differentiated Positivist from Pragmatist verificationism, more will be said about Ladyman and Ross’s use of Pragmatist verificationism in a future post. This will address the core of their epistemology.

Notes

1. Ladyman and Ross, Every Thing Must Go,  p. 303.
2. ibid., p. 27.
3. Rudolf Carnap, “The elimination of metaphysics through logical analysis of lanaguage,” p. 65 in James Ladyman, Understanding the Philosophy of Science, p. 150.
4. Ladyman and Ross, Every Thing Must Go,  p. 28.
5. Ladyman and Ross’s entire book is devoted to clarifying the precise way in which this sentence is true. My statement here is simplistic to the point of being false, but providing more detail at this point would confuse the larger point at work.
6. C.S. Peirce, “Questions concerning certain faculties claimed for man,” 5:213-263 in Hilary Putnam, “Pragmatism,” p. 292-3.
7. Ladyman and Ross, Every Thing Must Go, p. 29.
8. ibid., p. 310.