The term ‘realism’ designates a class of philosophical doctrines about reality.
What these doctrines have in common is the claim that we confront a material world, existing objectively and independently of our thought and experience.
Typically, this ontological claim is accompanied by the epistemic claim that we can and indeed do have knowledge of the external world.
Upon careful inspection, the ontological thesis reveals two dimensions of realism: an independence dimension, and an existence dimension. An entity exists independently in that it does not depend on our epistemic capacities.
In other words, “it is not constituted by our knowledge, by the synthesizing powers of our mind, nor by our imposition of concepts or theories.” (Devitt 1984: 13). In this sense, Kant’s phenomenal world and Goodman’s world-version (see 6.3) do not have independent existence.
Realism allows for a part of the world to be dependent on our epistemic capacities. As will be shown in chapter 6, we can accept that many facts about the world are social constructions. However, it is presupposed that there is a brute external world out of which these facts are constructed. The view that all the facts about the world are constructed represents a radical kind of constructivism (see 6.1) which splits with realist assumption of an external material world. A corollary of this assumption is that the world does not entirely consist of mental states.
The realist’s antagonist in this dimension is the idealist. The idealist argues that the mind (or spirit) constitutes a fundamental reality and that the physical world exists only as an appearance to or as an expression of the mind. The radical constructivist is an idealist, one who, following Berkeley, thinks of physical objects as collections of sensory ideas.
The existence dimension of realism is concerned with the entities that are
claimed to exist. We can picture the existence dimension as a vertical one, having at its lowest level the claim thatsomething exists objectively and in-dependently of the mental (Devitt 1984: 15). Devitt labels it a fig-leaf real-ism, committed to nothing above an undifferentiated and uncategorized brute world. This might be Goodman’s (1978) world “without kinds or order or motion or rest or pattern”, “a world not worth fighting for” (1978: 20). (We shall see in chapter 6, when discussing the spatial and temporal inconsistencies of constructive empiricism, that this world is not as worthless as some seem to believe.)
Next on the vertical dimension comes the claim that common-sense enti-ties, such as stones and trees, exist independently of us, thus representing a commonsense realism.
A significant move upwards on the vertical dimension consists in the claim that the unobservable entities posited by scientific theories, such as electrons and genes, exist independently of us. This describes scientific realism, the doctrine we are mostly concerned with here.
Finally, to maintain that abstract entities – that will be labelled in section 6.1ideas– such as numbers, values, propositions, etc., exist, is to adoptabstract realism.
As Kukla (1998: 4) remarks, in spite of the logical independency of these sorts of realism, there is a tendency of those who adopt any of these levels to accept all the lower levels. Scientific realists are most of the times commonsense realists, as abstract realists have no problems in admitting both the existence of stones and of electrons. However, there are notable exceptions. Platonism is a species of abstract realism which admits exclusively the existence of abstract entities.
The above mentioned epistemic claim presupposes, as Wright (1993) puts it, two sorts of ability:
the ability to form the right concepts for the classification of genuine, objective features of the world; and the ability to come to know, or at least reasonably to believe, true statements about the world whose expression those concepts make possible. (Wright 1993: 2)
The epistemic opponent of the realist is the sceptic. The sceptic does not dispute the independent existence of an external world, but refuses to admit that our epistemic practices can provide us with knowledge or warranted belief about this world.
Wright’s above passage also introduces a semantic aspect in the discussion of realism: the truth of the statements about the world. The semantic issue of realism is whether truth is an objective relation between language and reality.
It is common to take semantic realism as defining truth as a correspondence
between language and reality. However, one ought to note the diversity of views about truth within the realist camp. Most of the scientific realists em-brace indeed a correspondence theory of truth. Among them, some take truth as constitutive of realism: Hooker (1974: 409) states that realism is a semantic thesis, “the view that if a scientific theory is in fact true then there are in the world exactly those entities which the theory says there are. . . .”; Ellis defines scientific realism as the view that “the theoretical statements of science are, or purport to be, true generalized descriptions of reality” (1979: 28); according to Hesse (1967), realism holds that “theories consist of true or false statements referring to ‘real’ or ‘existing’ entities.” (1967: 407). Other supporters of the correspondence theory of truth believe that scientific realism has nothing es-sential to do with truth (e.g. Devitt 1984; 2001). Nonetheless, other realists believe that truth has no nature at all, hence no bearing to scientific realism.
The deflationary views – Ramsey’s (1927) redundancy theory, Quine’s (1970) disquotationalism, Horwich’s (2001) minimalism – share the conviction that there is nothing more to the truth of a sentence/proposition than our com-mitment to the sentence/proposition itself. It is also interesting how most antirealists find it convenient to construe scientific realism in terms of the cor-respondence theory of truth. Van Fraassen, for example, ascribes scientific realism the claim that “science aims to give us, in its theories, a literally true story of what the world is like” (1980: 8).
After having described the issues of the ontological, the epistemic, and the semantic aspects of realism, it is important that we keep them distinct.
Provided that one believes in ontological realism, it is optional for one to be an epistemic, and/or a semantic realist. For one thing, one may subscribe to ontological realism without epistemically doing so: belief in the existence of an external world does not entail that this world is in any sense ascertainable to us. The reverse does not hold: one cannot have knowledge about the world if there is no world. It follows that epistemic realism logically entails ontological realism. For another, one can be a semantic realist without thereby being an epistemic realist: one can maintain that statements about the world have truth-values, regardless of whether we can come to know them or not. At the same time, epistemic realism cannot be in place without semantic realism. One cannot have knowledge about anything in the world unless statements about the world are truth-valuable. It follows that epistemic realism logically entails semantic realism.
The conceptual relation between ontological and semantic realism seems to be one of independence. On the one hand, one can admit the independent existence of a physical world without for one’s beliefs to refer to anything in the world. Thus, ontological realism does not entail semantic realism. On the other hand, semantic realism specifies how the world should be like in order to
make sentences about the world truth-valuable (i.e. either true or false). This in no way involves commitment to the view that the world is indeed like this.
Thus, semantic realism does not entail ontological realism.
Certainly, these conceptual relationships should not hinder our awareness of the intertwining of ontological, semantic, and epistemic issues in aconstitutive sense: the ontological thesis has been formulated in terms of external world’s independence of our epistemic capacities. Besides, both the ontological and the epistemic thesis ought may need to be subjected to ameaning analysis.