by Michele Marsonet (University of Genoa, Italy).

Nicholas Rescher’s work can be deemed as a serious endeavor at both reviving the idealist perspective within contemporary analytic philosophy and making it compatible with a scientifically oriented outlook on reality. However, Rescher’s conceptual and pragmatic idealism cannot be defined as a “true” idealism because, while adopting an idealist stance at the epistemological level, he nevertheless endorses a clearly realist position at the ontological one, and this means that a non-dogmatic realism can actually be compatible with his position. Furthermore, his particular brand of idealism gives rise to a rather flexible system, which can face criticisms without giving up its premises. Now I would like to make clear and possibly deepen this remark taking into account more recent articles of his. I believe in fact that the issues raised by Rescher are important for both a correct understanding of the current realism/anti-realism debate in metaphysics and the philosophy of science, and for the clarification as well of the manifest (although often undeclared) “idealistic turn” which took place within analytic philosophy in the last few decades.
Just to understand the real problem at stake here, let us single out a statement that may be found at the beginning of Rescher’s paper on conceptual idealism: “Idealism, broadly speaking, is the doctrine that reality is somehow mind-correlative or mind-coordinated. However, the specifically conceptual idealism which concerns us here stands in contrast to an ontological doctrine to the effect that mind somehow constitutes or produces the world’s material.”
As I see it, precisely this ontological doctrine is the core of both classical idealism and the many forms of neo-idealism which have been thriving up to the present day within Western philosophy. A short historical inquiry, in fact, will make us recognize that idealism is the philosophical doctrine according to which the existence of the world (reality) is either logically or causally dependent on the existence of some kind of mind. This mind, in turn, may be human or divine, but such a further distinction is not important for our present purposes. Rescher thus clearly rejects from the beginning the most characterizing feature of both classical idealism and contemporary neo-idealism, claiming explicitly that his conceptual idealism stands in contrast to the aforementioned ontological doctrine. The importance of this move needs not to be stressed, because it is well-known that the basic anti-scientific attitude endorsed by the classical idealists and the contemporary neo-idealist thinkers stems precisely from it: why should we deem natural science important if it deals with a second-level reality, i.e., with a reality that is “secondary” being merely a creation of the human (or divine) mind (or spirit)? According to this view, only philosophy – or some type of philosophical theology – can actually reveal to us the real “essence” of the world, given the fact that the mind/spirit creates reality as a counterpart to itself.
In Rescher’s conceptions, however, we find nothing of this sort. Not only is physical reality irreducible to mind; he claims, furthermore, that natural science gives us a fairly adequate picture of reality, although warning against the diffused temptation of conceiving our actual science as a perfect and final representation of reality itself. No doubt, neither Hegel and the founding fathers of classical idealism, nor Bradley, Croce and other more recent neo-idealist philosophers would find themselves at ease with such statements. And the picture gets even clearer if we add that, as mentioned above, the ontological independence of the physical world is explicitly admitted by Rescher. The problem, then, is to find a rationale for what he often calls “intimations of idealism.
Rescher’s epistemological idealism is stated as follows: “[Conceptual idealism] maintains that an adequate descriptive characterization of physical (‘material’) reality will always involve an implicit reference to mental operations – that some commerce with mental characteristics and operations always occurs in the explanatory exposition of the ‘real world’ “.
After making clear that a “real world” exists, it cannot be identified with the mind and is not created by our conceptual apparatus either, Rescher goes on adopting a position which the realist can accept sub condicione, i.e. posing conditions we shall take into account later on. His main aim, in fact, is to distinguish between:

(A) Nature-as-we-understand-it, and
(B) Nature itself.

Is this distinction ontological or epistemological? To answer this question, we must trace a line of separation between ontology and epistemology and, since Rescher is inclined to accept such a division (unlike many other thinkers nowadays), we are entitled to claim that ontology aims at discovering what kind of entities make up reality (“what there is”, to use a Quinean expression), while epistemology’s task is to discover the principles by which we get to know reality. The importance of this step is in my opinion crucial.
Going back to the aforementioned distinction between (A) and (B), in fact, it is clear that we are after all allowed to make an ontological distinction between them, but with an important caveat: only (A) is mind-dependent, in the sense that a hypothetical complete disappearance of mankind would make it disappear too, while (B) is neither created by the human mind nor dependent on it. Men can understand nature itself (i.e., B) in a great number of different ways, and the history of astronomy and cosmology gives us a clear picture of this situation. Our distant ancestors believed that the Earth was at the center of the universe, while a few centuries ago it was discovered that it is simply a part of a vaster system of planets rotating around the Sun. More recently the solar system turned out to be a very tiny part of an even vaster system called galaxy, and our galaxy eventually was discovered to be a rather small part of an extremely complex system made up by billions of galaxies. And the story is by no means concluded, since the correctness of the current standard theory about the origin of the universe – the Big Bang model – has not been demonstrated with absolute certainty.
So nature-as-we-understand-it really changes. Our vision of it is quite different from the vision held by the ancient Greeks, the men living in the Middle Ages, the founding fathers of the United States of America, or even the men living in 19th century imperial Britain. The question to ask at this point is the following: What follows from this from an ontological point of view? In my opinion the answer is not as difficult as many contemporary philosophers seem to believe. No matter how much our visions of nature change, nature itself does not change for that reason. Some thinkers nowadays claim that history of science shows the impossibility of adopting an ontology which is absolute and mind-independent, and even say, for instance, that the world of the ancient Greeks is just different from our world. This may certainly be correct, provided we give a clear definition of the term “world” (reality). If they mean that nature-as-the-Greeks-conceived-it and nature-as-we-conceive-it are just different pictures of the world that have an ontological import on their own, one cannot but say that they are right. If instead they mean that the ancient Greeks’ beliefs about their gods, the structure of Earth and heaven, etc., had a direct bearing on nature itself, then this is patently false. The ancient Greeks happened to live on an Earth which is also our Earth. The only difference between their Earth and ours – both conceived of in ontological terms – is given by time conceived as a characteristic of physical reality which, together with space, puts heavy constraints on what we may or may not do. Today we can, for instance, travel from Europe to the United States in a reasonably short time filling up a portion of space which was deemed almost insuperable by our ancestors. We cannot, instead, travel back in time to the Rome of Julius Caesar, nor can we fill up the portion of space-time which separates our planet and galaxy from other distant galaxies of the universe. These possibilities (and impossibilities) in turn are just a contingent fact, i.e. the consequence of how the universe – and the human beings who are part of it – are made.
Resuming the previous distinction between (A) and (B), I think we are now in a better position to judge the status of both its constituting elements. (A), i.e. nature-as-we-understand-it, is subject to continuous changes due to our ever deepening comprehension of (B), i.e. nature itself. Science is precisely the attempt at getting a good knowledge of nature itself, and it does not matter very much if we believe – with Rescher – that science will never be completed, or if we believe instead – with the physicist Steven Weinberg – that contemporary science is very close to establishing what he calls the “final theory”. It is not important for our purposes because, in any event, we are not jeopardizing the distinction between an ontologically mind-independent reality and the representation we build up of it, given the particular and contingent features of our conceptual apparatus.
In order to enforce what we just said, I would eventually like to mention two additional examples of Rescher’s basic ontological realism. He states in fact:

“In attempting answers to our questions about how things stand in the world science offers (or at any rate, both endeavors and purports to offer) information about the world. The theory of sub-atomic matter is unquestionably a ‘mere theory’, but it could not help us to explain those all too real atomic explosions if it is not a theory about real substances. If I hypothesize a robber to account for the missing jewelry, it is not a hypothetical robber that I envision but a perfectly real one. Similarly, if I theorize an alpha particle to account for that photographic track, it is a perfectly real physical item I hypothesize and not a hypothetical one. Only real objects can produce real effects (…) The theoretical entities of science are introduced not for their own interest but for a utilitarian mission, to furnish the materials of causal explanation for the real comportment of real things (…) What science says is descriptively committal in making claims regarding the real world, but the tone of voice in which it proffers these claims always is (or should be) provisional and tentative (…) Thus our inability to claim that natural science as we understand it depicts reality correctly must not be taken to mean that science is a merely practical device – a mere instrument for prediction and control that has no bearing on describing ‘the nature of things’. What science says is descriptively committal in making claims regarding ‘the real world’, but the tone of voice in which it proffers these claims always is (or should be) provisional and tentative.”

The picture is even more complete if we recall that, in Rescher’s view, “Instrumentalism puts the cart before the horse. As far as the working scientist is concerned, scientific theories do not exist for the sake of prediction and control, but the other way round – prediction and control are of interest because they serve to monitor the adequacy of our theorizing about objective reality”. It seems very clear to me that here we have the explicit admission that there is an external reality which is not created by our mind or thought, however strong the epistemological constraints that our mind or thought imposes on that reality may be. We have, in sum, neither the classical idealism of the past century, nor the neo-idealism of our century, nor eventually a form of linguistic idealism.

At this point there is nothing that prevents us from agreeing with Rescher when he argues that “an adequate descriptive characterization of physical (‘material’) reality always involves an implicit reference to mental operations”. This statement, in fact, is tantamount to recognizing the well-known fact that we get in touch with reality – including ourselves as a part of it – through conceptualization which, in turn, can be expressed by means of thought plus language. And, having granted this fact, we must now try to verify what kind of consequences may be drawn from it. Since Rescher clearly states that mind is responsible for nature-as-we-understand-it, i.e. (A), and not for nature itself, i.e. (B), we have eliminated from the outset one of the major critical points of both classic idealism and contemporary neo-idealism. Idealism comes back, instead, when he claims that mind has a constitutive role in nature; that is, indeed, a characterizing point of every form of idealism, including the one endorsed by those analytic philosophers who assert that language has a constitutive role in the world. Soon after, however, Rescher clarifies at best his position, adding that this constitutive role of the mind must be taken neither in ontological nor in causal terms, but rather from a hermeneutic viewpoint.
So we face a situation of the following kind. On the one hand, mind does not produce nature but, on the other, we always need the analogy of mind for conceiving nature itself: our reference to the external world is always mind-correlative. Here we have another crucial passage which involves the presence – or not – of a priori factors in our knowledge of reality. A short reflection, in fact, makes us understand that starting from the aforementioned considerations two different paths can be taken according to the definition of “conceptualization” one is ready to endorse. In other words we can choose a Kantian-flavored solution, saying that our conceptualization of the world takes place because in our mind a creative element is present, i.e., some faculties or categories that cannot be found in nature and are an exclusive feature of the human mind. These faculties or categories shape external reality in a certain way that is common to all men qua men: for instance, they allow us to conceive things ordered in causal relations, placed in space and in time, etc. And right here idealism acquires a great role, because if this Kantian-flavored position is correct, then it is obvious that man is not a mere part of reality but is entitled to claim a much more important status. He becomes somehow a creator of reality.
What really strikes one in this position is that it is quite hard to understand how this creative human capacity fits in the order of nature and why it came into being at all. We had on our Earth a natural process of evolution which, although not completely known thus far, can nevertheless be described with sufficient precision. In this process man comes on the stage relatively late – according to cosmic standards, of course – and gradually (i.e., not at once) acquires a predominant position thanks to his capacities which are in turn a product of natural evolution. These capacities, however, must not be seen as a violation of the previous natural order if we want to be consistent with a scientific picture of reality; they are, rather, a higher step in the development of this same natural order, and conceptualization is thus a tool that allows man to get both a better picture and a reasonable control of what lies outside him. Note that if we take this second path, the human capacity of conceptualizing becomes something natural and explainable, although our comprehension of its historic origin and concrete evolution is by no means complete. But, on the other hand, there is no cogent reason for claiming that we will never be able to understand when and how mankind acquired the above mentioned capacity; I think it it reasonable to view it as a constantly growing addition of new skills to previous ones.
There is, obviously, a big why? behind all this. Even scientifically oriented thinkers like Karl R. Popper and Konrad Lorenz recognize that it is quite difficult to answer questions of this sort: Why did evolution take the direction we know? Why did life begin at all on the Earth?, etc. At this point we are bound to stress a very important fact indeed. If mind is allowed to be not only a complex natural structure that reflects an external reality, but also an ontological agent which possesses a priori faculties of the Kantian sort, one can reasonably ask: Where do these a priori faculties come from? By endorsing an aprioristic and Kant-style view, we are somehow forced to conclude that a significant violation of the natural order took place at an indefinite moment of time in the past. Something happened, even though we do not know precisely what, that endowed a finite being with superior capacities and, thus, we need to admit the presence of an agent who caused the aforementioned “something”. Granting that we can make as many hypotheses as we like, some kind of teleological principle viewing evolution as the means by which consciousness arises would now be justified and, to point out just one example out of many, the conceptions of the French thinker Pierre Teilhard de Chardin would thus be vindicated (at least in principle, if not in detail). According to this vision, only the presence of a priori mind-equipped beings would in fact justify the presence of a physical universe which, in their absence, makes no sense at all. To use one of Rescher’s examples, it might in fact be asked: “Why should there be any smelling of roses if there is no mind-equipped being who can smell them”? Or, to put it in a more straightforward way, who cares about a universe in which there are roses but no human subject who can smell them? But this reasoning is in my opinion unjustified, because it is tantamount to saying that the universe is significant only as long as men exist. I would like to make it clear that, following this path, we are abandoning the domain of philosophy to enter a new field of inquiry and, at this point, at least three choices are available:

(i) we may accept the violation of the natural order as an assumption based on some type of religious faith;
(ii) we may accept the violation of the natural order as an assumption based on faith, although maintaining a difficult equilibrium between faith and science;
(iii) we may refuse any violation of the natural order sticking to what science says.

In any event, it is clear that if we accept the aforesaid violation of the natural order without having a sound empirical evidence in its favor we are just abandoning the domain of rational inquiry, and this does not seem to be a justified philosophical stance. Furthermore, we can note that, in order to accept position (i), we do not even need to endorse a traditionally religious position. (i) is in fact compatible with the presence of a sort of Hegelian Spirit and with the philosophical theology that is today so popular and successful after having been revived by many authors belonging to the hermeneutic tradition.
This is not Rescher’s position, however, although he endorses the presence of a priori factors in our knowledge. We are then called to verify in what sense his conceptual idealism is different from other idealist stances that can be found in the history of Western philosophy. He depicts his outlook claiming that the key properties we ascribe to physical things are relational, in the sense that our conceptual scheme works in such a way that the properties we ascribe to those things always involve some type of reference to mental operations. According to my interpretation, these words mean that, no matter how physical reality – whose independent existence is beyond any doubt – is truly made, we always need a conceptual scheme to get in touch with it; note that the conceptual scheme is needed not only to ascribe properties to stars and galaxies, or tables and chairs, but even to the components of our own body (hands, feet, etc.). This body of ours is in fact part of the external reality, while the properties we ascribe to its components would, according to this picture, be assigned to them by our mind or conceptual apparatus.
Just take the following example: Does a particular tree have the shape it has because our mind attributes a shape to it, or is this shape something that our mind somehow reproduces picking it up from nature itself, i.e. (B)? Consider a particular (not a possible, but just a real) tree, say x. It happens sometimes that lightning burns a tree changing its shape, and suppose furthermore that lightning – say y – actually burned x changing its shape. In what sense is this change of shape – due to a natural phenomenon like the lightning y – dependent on men’s minds? I do not see any plausible idealistic answer except the Kantian one which, as I already pointed out, does not agree with what science tells us.
What I want to stress is, in sum, the following fact. The representatives of classical idealism, and Hegel in particular, recognized that idealism must – just to be consistent with itself – eliminate any separation between ontology and epistemology. Only by claiming that physical reality is a product of some kind of mind/spirit will it avoid the tension between a realist ontology and an idealist epistemology, and this is exactly what Hegel did by getting rid of the Kantian noumena, while on the other hand Marx took the opposite step in order to obtain a consistent materialist system. Now it is interesting to see how Rescher solves the old problem of the contemporary presence on the stage of a realist ontology and of a materialist epistemology. Are they truly irreconcilable even when taking his particular form of idealism into account.

At this point Rescher distinguishes between “conceptual mind-involvingness” and “explicit mind-invokingness” and picks up two different items in order to illustrate this distinction: books and dreams. A dream is explicitly mind-invoking because dreams can only exist where there are mind-equipped beings to do the dreaming, while books, being physical objects, seem at first sight entirely non-mental. Nevertheless books are mind-involving, because there could be no books in a world where minds had never been in existence. And he goes on claiming that:

“Even if there were no mind-endowed beings, there could certainly be naturally evolved book-like objects, objects physically indistinguishable from books as we know them (…) A book is, by definition, an artifact of a certain purposive (i.e. communicative) sort (…) To be a book is to have writing in it, and not just marks (…) To explain adequately what a book is we must thus make reference to writing and, in turn, ultimately to minds.”

We may summarize Rescher’s distinction saying that there are immaterial objects like dreams and worries – let us call them O1 – which are clearly mind-invoking, and material objects (human artifacts) like books – let us call them O2 – that are clearly mind-involving. In no way could they exist without the presence of human beings. It is in my opinion clear, however, that a third kind of object is needed to have a complete picture of the situation and to justifiy the separation between ontology and epistemology that Rescher ultimately accepts. This third kind is formed by physical objects – we may call them O3 – which are neither human artifacts nor mind-dependent. If we take a typical O2 object like a book, in fact, it is easy to see that it is made of paper (another O2-kind human artifact), but in order to produce paper we need a physical O3-kind object like cellulose which can hardly be deemed to be mind-dependent (it gets in touch with our mind, and this is a completely different story). So, while it is correct to claim – as Rescher does – that “a world in which there neither are nor ever have been minds can contain objects physically indistinguishable from our books and nails, but books and nails they could not be, since only artifacts created for a certain sort of intelligence-invoking purpose can correctly be so characterized”, I think that we must add something else. Leaving aside “possible” entities like book-shape objects indistinguishable from our books, what we need is a realm of physical objects that are not made up by us, i.e. a mind-independent external reality.
Here, however, even a further step is mandatory. Let us think of reality-as-we-conceive-it, i.e. the aforementioned (A) in Rescher’s previous distinction. We have already established that it cannot be identified with (B), i.e. nature itself which, as such, is mind-independent. What are we supposed to do with (A)? A naive realist would most likely answer that we do not need it: being a product of our conceptual apparatus, we can just rule out the possibility that it has any ontological value whatsoever. I do not find this position acceptable, though, and for a very simple reason: How can we deny the existence of entities like dreams and worries which are clearly there, although not in the same sense as physical objects are? The fact of the matter is that, as Aristotle claims, “being” can be talked of in many ways. We live in an extremely complex reality. Besides facing an external world which is not produced by us, we also build up a reality which is the product of our mind. On the one side (i) we cannot identify those two kinds of reality, but on the other (ii) we can neither deny existence to one of the two, because it is a fact that they both exist, nor (iii) can we divide them with too rigid a boundary. There is in fact continuity between (A) and (B): neither a dream can be separated from the subject who dreams it, nor a worry can be detached by the subject who holds it.
The best thing to do, then, is to attribute to them a different – but not totally separated – kind of existence. It is by no means correct to claim that my worry that the book I am writing will not be published is “unreal”; it is as real as the desk I am writing on because both of them are present, so that both are endowed with some kind of existence. In order to clarify the issue, let us draw the following distinction:

(1) There are O1-kind objects like dreams. Their existence, however, is strictly dependent on human minds, in the sense that, should mankind disappear, there would no longer be dreams;
(2) There are O2-kind objects like books. Their existence is still tied to human minds as far as we consider both their contents (ideas and theories contained in the books, etc.) and their shapes (their book-like appearance), but not when we take into account their ultimate material ingredients which belong to an external and mind-independent reality;
(3) There are O3-kind objects like trees from which the cellulose we use to make paper (and thus books) ultimately comes. Their existence is not dependent on human minds.

Quine, of course, would disagree with such an “overcrowded” ontology but, as previously noted, I think that Ockham’s razor, which he so often applies, poses too many problems to be adopted uncritically. Quine is still prisoner of the positivist dogma according to which “real” is only what can be empirically observed, a dogma that contemporary science has shown to be untenable. If reality is complex, ontology is bound to be complex as well: we cannot oversimplify reality according to our personal opinions. So we have two kinds of existence, a conceptual existence E1 which is predicated of conceptual reality: it is tied to our conceptual apparatus and is bound to vanish along with it. Secondly we have an absolute existence E2, which is predicated of external reality and is not bound to vanish along with our conceptual apparatus. It should be clear, however, that both kinds of existence are real, the only difference being that E1 is tied to worlds in which men with their minds are present, while E2 has a broader range, since it is relative to any kind of world, either inhabited or not by men-looking and mind-equipped entities. Note, however, that I did not employ the notion of “possibility” because, in this context, it would be a source of dangerous misunderstandings. Mentioning worlds devoided of human presence I do not mean “possible” worlds in a metaphysical (Leibnizian) or logical (modal) sense, but just worlds ontologically as real as our Earth: as we remarked before, both paleontology and astronomy give us examples of such worlds, and this is a sufficient reason for rejecting the ontology of classical idealism and of contemporary neo-idealism (which is different, as we already saw, from Rescher’s).
At this point we no longer have the incompatibility between a realist ontology and an idealist epistemology. Granting the mind-independent existence of reality itself, we can admit without problems not only that:

(1) mind shapes reality as-we-conceive-it;

but also that:

(2) only through mind can we get in touch with reality itself.

Unlike the other entities that form reality itself, in fact, we are mind-equipped, which means that we get in touch with external reality through conceptualization. However, since this faculty needs not to be assimilated to the a priori faculties envisioned by Kant and then taken up by the classical idealists, but may instead be explicable as the outcome of a natural process of evolution, we do not need to assume, either, that reality itself exists as long as it gets in touch with our perceptual apparatus. We are indeed creators of some type of reality, i.e. reality-as-we-conceive-it, and in this sense dreams, worries, literature, philosophy, etc., are all products of the human mind. But certainly we do not create trees, stones, atoms, planets, etc. On the contrary, we can even formulate the following hypothesis. While it is reasonable to assume that the structure of the world-as-we-conceive-it reflects the structure of the mind, I see plenty of reasons for claiming as well that the structure of our mind reflects that of a world mind it must comply with in order to survive along the path of a long evolutionary process. Mind thus simply becomes, according to this vision, the terminal (by now) point of an evolutionary (natural) process which is still under way. Our world (i.e., nature-as-we-conceive-it) would not even exist without mind’s capacity of conceptualizing and, as a matter of fact, we cannot even imagine a different way for getting in touch with reality itself. Certainly no “vision of the world” would then be possible.
But the point I want to stress is that the physical universe did not wait for our vision (or, better, visions) of it in order to exist. The evidence of physical worlds devoid of human presence is so overwhelming that I do not really see how this argument might be rejected. After all, it is simply a contingent fact, and not a necessary one, that human life evolved on our planet and, at the present stage of scientific research, we do not even know whether something comparable to human life and mental activity developed on some planets belonging to our or other galaxies. Reality, as it may be, is divided into parts. I am just a part of reality, and the tree is another part. Our final constitution is essentially the same, being reducible to ultimate components. Now, it happens that within me some chemical reactions take place, while within the tree other chemical reactions take place: life, in sum, manifests itself in different ways. This line of thought allows us to naturalize all the alleged a priori faculties that an important part of Western philosophy has put forward in order to explain our knowledge of the world.