Reality

The conventional view of reality is grounded upon perceptions of the world as we experience it, and reflection concerning such perception. This view is related to, but not identical with, empiricism. Perspectives depend upon a particular point of view. There could be as many perspectives as there are people. However, because reality relies to some extent on shared understanding concerning individual perceptions, reality falls within convention. Views of reality have greater or lesser degrees of refinement and organization. Some are highly systematized, for example, scientific theories that use specialized methods to verify their findings, and other views are based upon mores or societal institutions.

Because of the regress problem, establishing a foundation of truth and reality is a problematic that underlies all disciplines, including mathematics. The regress problem (in a nutshell) is that every proposition rests upon premises, which in turn are based upon underlying premises, and so on. Thus, the underlying reality is subject to regress. The desire to establish an underlying ground of all or part of reality, that is, to say what reality "really is," has been a long-standing preoccupation of philosophy and the sciences.

Platonic Realism

Plato's philosophy concerns the nature of Being itself, "what is" ; it distinguishes between "what is" and material existence. What is Real is "what is" in itself; for Plato, these are the 'Forms'. Here is derived the term "Platonic Realism" which refers to a view of reality that grounds truth (the ultimate Reality) in a Being (the Forms) outside sensible reality, and beyond the Forms in the Good that is beyond Being. The Platonic Theory of Forms does not depend on sensible perception to ascertain truth but on another form of 'seeing' that is only possible for the soul [Ψυχή]. In the myth of the charioteer, Plato argues, "For a human being must understand a general conception formed by collecting into a unity by means of reason the many perceptions of the senses; and this is a recollection of those things which our soul once beheld, when it journeyed with God and, lifting its vision above the things which we now say exist, rose up into real being" (249c).

In Plato, Being is itself and nothing but itself. Thus, the Form of Justice is simply Justice itself. To define, we use predicates, but a Form would have no predicates in the usual sense of such things, since a Form's definition would give you something that has the same thing on either side such that Justice=Justice. No matter what predicates you add to a thing itself [the Form], for Plato, it remains the same. On the other hand, when we say that Mary has blue eyes and Bill has brown eyes, we refer to items pertaining to sensibility and particular biological traits.

Given his definition of Reality, it is easier to see why, for Plato, knowledge is not 'acquired', but involves anamnesis. Real knowledge involves a vision of the shining of the Beautiful, its Eidos. For one thing, how would we bring something immutable into material life, such that we could acquire it? For another, would we acquire the Being of the Beautiful or merely another image of the Beautiful? Conversely, the objects of immanent, sensible experience remind us of the things themselves: we see a bed, and this evokes the Idea of a bed, and so on. Knowledge is the extent to which you can connect the bed of experience to the immutable Form of the bed (597a-598b).

So there is a Form of the relation between numbers, the Form of specific numbers, and the Form of the abstraction of 'number' itself. In immanent existence, these forms are all mixed up in matter and predicates abound. But what of the varying degree to which some of us are able to make these relations, to gain knowledge? I may see a beetle climbing on a branch and think about bugs. If I am no entomologist I may not go to the specific Form of 'beetle', only the form of a beetle in general. My inability to understand the intricacy of number does not prevent me from a vision of the form of 'number' in general or its abstraction, but may prevent me from seeing the intricacy of their relationships.

Because the Forms are external to the sensible copies of reality, it does not seem that there can be change in something like Beauty or Justice. Immanent life seems to confirm this, finding because objects of sensation appear to be all mixed up together. We see justice and truth in varying degrees, as composed in matter, rather than by themselves. These break, degrade, disperse or scatter. Plato's explanation is that the beautiful we experience is beautiful because it participates in the Form of Beauty, not because it is beautiful in itself. Accordingly, if I want to know if a sunset is beautiful, I go to the Form that gives the sunset its beauty. The relation of the particular sunset to Beauty remains temporary (the sun goes down, although the beauty of the sunset cannot fade). Perception of beauty in this world involves establishing such a relationship between objects of sensation and that which is truly Beautiful. Unlike finite beauty, the Form of the Beautiful has no beginning or end (when we perceive the beautiful sunset as being present, we are soon dissuaded of this reality when we perceive that the facts have changed and are now otherwise once the sun goes down).

Further, to understand Plato's conception of Reality, we must get around the idea of causality. The Real does not come to be and cease to be in a material sense. The scientific cause of the 'appearance' of a sunset, the appearance that the sun moves, for us has to do with the movements of bodies in space but from a Platonic view implies a connection to the Form that is the underlying cause of the sun or of a sunset seen in in our experience. The bond to the Beautiful of the sunset or to the Form of the sun itself is real, but the objects we think of as sun or sunset do not amount to things in themselves. All we have done in locating these objects is to establish a relation to Reality.

Conventional reality, for Plato, is unsatisfactory, and knowledge of this type of reality can be categorized as doxa, the stuff of beliefs and opinions, rather than the act of real knowledge. Yet it should not be concluded that Plato rejects all doxa. Including "geometry and the kindred arts," Plato asserts that, through the power of dialectic (as he conceives of it), reason can treat "its assumptions not as absolute beginnings but literally as hypotheses, underpinnings, footings, and springboards so to speak" (511b).

Model-dependent realism

The Platonic approach described above is of very broad scope. A much more restricted concept of "reality" in science is limited to the explanations of observations or measurements, probably a view of reality that Plato would discount. Plato would require that "reality" transcends any feeble attempt to confine it to a particular set of observations, particularly as this reality changes with the introduction of additional observations admitted to explanation as technology evolves.

More recently the connection of theory to reality has been explored by physicists Stephen W. Hawking and Leonard Mlodinow. In their book, The Grand Design, they assert that there cannot be a theory-independent , or picture-independent, concept of reality. They point out:

• that either an earth-centered (Ptolemaic) or a sun-centered (Copernican) picture of reality can be made consistent with the motion of celestial bodies;
• that goldfish physicists living in a curved bowl, though observing curved paths of motion of bodies that we observe as linear, could still formulate predictive laws governing motion as they see it;
• that we cannot know whether we live in a simulated world, a virtual reality, one that the simulators rendered self-consistent.

Each of those concepts of reality are picture- or theory-dependent.

In that regard, they articulate a view of reality they call model-dependent realism:

Instead we will adopt a view that we will call model-dependent realism: the idea that a physical theory or world picture is a model (generally of a mathematical nature) and a set of rules that connect the elements of the model to observations. This provides a framework with which to interpret modern science.

According to the idea of model-dependent realism...our brains interpret the input from our sensory organs by making a model of the outside world. We form mental concepts of our home, trees, other people, the electricity that flows from wall sockets, atoms, molecules, and other universes. These mental concepts are the only reality we can know. There is no model-independent test of reality. It follows that a well-constructed model creates a reality of its own.

In adopting model-dependent realism, "it is pointless to ask whether a model is real, only whether it agrees with observation" (p. 46). If two different models agree with the observations, it does not make sense to consider one more true than the other, that one gives a truer picture of reality than the other, though one or the other may be more convenient to employ in a given situation, or otherwise more appealing.

Some find the ambiguity of reality introduced by alternative equivalent theories to be in itself an argument that such definitions of reality are inadequate. That argument, however, has to be based upon criteria arrived at from outside model-dependent reality, and an example of such criteria is provided shortly.

It should be emphasized that there is no restriction in model-dependent realism to observable or measurable constructs. The alternatives:

Do unobservable theoretical entities such as quarks and gluons really exist in the physical world, as objective entities independent of human will, or exist merely as human constructions for their utility in organizing our experience and predicting future events?

are addressed by Hawking/Mlodinow in their model-dependent realism approach as follows:

QCD [Quantum chromodynamics] also has a property called asymptotic freedom, which we referred to, without naming it, in Chapter 3. Asymptotic freedom means that the strong forces between quarks are small when the quarks are close together but increase if they are farther apart, rather as though they were joined by rubber bands. Asymptotic freedom explains why we don’t see isolated quarks in nature and have been unable to produce them in the laboratory. Still, even though we cannot observe individual quarks, we accept the model because it works so well at explaining the behavior of protons, neutrons, and other particles of matter [Emphasis added].

In short, in the alternatives posed above by Cao, model-dependent realism adopts the second view, accepts the unobservable constructs as aspects of reality, but rejects any posit of "objective" reality, which last is considered to be a chimera, like visions of oases in the desert.

The "reality" of science, even when restricted to the interpretation of observations and measurements, has been much discussed before Hawking and Mlodinow. Pierre Duhem (1861-1916) held that while physical theory was no more than an aid to memory, summarizing and classifying facts by providing a symbolic representation of them, the facts of physical theory are to be distinguished from common sense and metaphysics. His views were further developed by W. V. O. Quine (1908-2000), who suggested "“our statements about the external world face the tribunal of sense experience not individually, but only as a corporate body”. It is impossible to test a scientific hypothesis in isolation, but only as part of a system. These two authors were much concerned with how a theory was coupled to concrete observation and measurement, and how it morphed with admission of new data.

Model assessment

For many, probably including Hawking/Mlodinov, model-dependent reality may be seen as only a partial description. For example, many complain that quantum mechanics, despite its experimental success, is "not accompanied by an interpretation that is widely convincing." Steven Pinker discusses this question using several quotations, including one from Murray Gell-Mann that describes quantum theory as: "that mysterious, confusing discipline which none of us really understands but which we know how to use." Hawking/Mlodinov suggest a "good model" has these characteristics:(p. 51)

1. It is elegant
2. Contains few arbitrary or adjustable elements
3. Agrees with and explains all existing observations
4. Makes detailed predictions about future observations that can disprove or falsify the model if they are not borne out.

These desiderata of a "good model" have justifications outside the tenets of model-dependent reality, and allow critique of different models that are equal from the stance of model-dependent reality by itself. The features of a "good" theory have been debated for centuries.

Unfortunately, even the most successful model of modern science, the Standard Model of particle physics, satisfies only the last criterion. As said by Hawking/Mlodinov (p. 52):

..many people view the "standard model" ...as inelegant. ...it contains dozens of adjustable parameters whose values must be fixed to match observations, rather than being determined by the theory itself.

The Standard Model fails the third criterion in not encompassing gravitation. Hawking/Mlodinov (p. 58) deal with the failure of a theory to encompass all observations using the notion of a network of overlapping theories, each describing some observations and agreeing with one another where the theories overlap. To quote:(p. 58):

No single theory within the network can describe every aspect of the universe... Though this situation does not fulfill the traditional physicists' dream of a single unified theory, it is acceptable within the framework of model-dependent realism.

Presumably, each theory included in a network provides concepts for a "model-dependent realty", though that reality is restricted to the domain of data to which it applies. Where these model-dependent realities overlap, multiple interpretations of reality are available of equal value.

Data collection

...the measuring device has been constructed by the observer, and we have to remember that what we observe is not nature in itself but nature exposed to our method of questioning. —Werner Heisenberg, Physics and Philosophy

The definition of model-dependent reality given by Hawking/Mlodinow is pretty straightforward if one has in mind a particular set of data to explain. Either the model explains the data or it doesn't, and if two models explain the data differently, any claim for the concepts employed by either as more true of "reality" must be based upon criteria lying outside the reach of model-dependent reality, such as the desiderata for a "good model" listed earlier.

The matter is less clear when one considers the selection of just what "data" must be explained. Our senses are limited, and we accept that we cannot see and hear everything that comprises reality. So we supplement the senses, for example, by using a telescope or a microscope. Historically the issue arose as to whether such instruments deceived us, and gradually they have been accepted as extensions of our natural capacities.

The gathering of "data" supplementing our senses has gone far beyond the primitive telescope to its modern version (for example, the Hubble telescope) and the microscope to its modern version (for example, the scanning tunneling microscope). Today experiments may require expensive apparatus not available to all, involving observations not even interpretable by many. Examples are the colliders of high-energy physics, and the sophisticated electronic image acquisition of modern astronomy, guided by elaborate computer processing and filtering. One might reasonably ask how well the acquisition of "data" is separated from the "theory" that explains how the acquisition process works, and that often suggests where to look for new "data". The process by which data is allowed into the theory influences what is incorporated into "reality".

The gathering of data is complicated by the limited access to these data-acquisition instruments, both in a required training that could be seen as indoctrination (not necessarily deliberate, but de facto), and in limitations upon who, and what investigations, are worthy to use the instruments, as determined by various funding agencies and corporate laboratories. Although censorship is not the motivation directing government and corporate support, a preoccupation with popular and/or commercially attractive projects draws resources and talent away from less conspicuous goals potentially of more significance to a comprehensive "reality". In effect, the expense and expertise of modern research result in blinkers.

The analysis as well as the gathering of data is becoming more complicated as our very notion of thinking, even of mathematical proof, is modified by technology, for example, by computers. Theoretical predictions are made by computer simulations that perform calculations beyond human capacity. The concepts entering a model-based reality may be only implicit in a computer programmable code, in open-ended algorithms, and may not be concepts the human mind is aware of directly.

To a limited degree, the shaping of "reality" based upon modeling of selected data is a public enterprise, with all the foibles that implies. The public does not engage reality at a specialized deeply technical level, but at a metaphoric level:

All theories have metaphorical dimensions...that give depth and meaning to scientific ideas, that add to their persuasiveness and color the way we see reality."

An explicitly metaphoric public participation is "eco-consciousness". Metaphorical involvement also is evident in arenas such as gene research and genetically altered organisms, and investigations of stem cells, where the public is actively engaged. Another example is archaeology and the limitations exerted upon examination of burial sites. In some cases public participation leads to simple clamor, as in the case of global warming. This broad public engagement, frequently informed by vested interests and oversimplifications, facilitates manipulation by groups with their own objectives, similar to the censorship found in the times of Vesalius and Galileo although lacking some of that institutional authority.

Although the above examples suggest an indictment of metaphor as a foible of public participation in shaping reality, public engagement in some form is necessary and desirable, and ultimately a goal of the entire enterprise.

Religion

Religion commonly ties reality to the notion of the divine. Thomas Aquinas, for example, says that statements about everyday reality are true of God only metaphorically. Similar ideas can be found in Buddhist traditions.

...to each species belongs its own mode of perfection and being. The same is true of whatever names designate the properties of things, which are caused by the proper principles of their species. Hence, they can be said of God only metaphorically. But the names that express such perfections along with the mode of supereminence with which they belong to God are said of God alone. ... Thomas Aquinas

To aid in interpretation of these remarks, we have:

It is not too much to say that, for Thomas, as for Aristotle, the forms in the natural world attain an altogether higher level of reality in our minds – because, as already for Aristotle, the world constitutes an intelligible whole in virtue of its dependence upon the divine mind. ... Fergus Kerr