The Nature of Substance, Reality, and Mind: Idealism, Dualism, and Materialism.
There are a number of complex philosophical issues brought about by a discussion of substance. As you may recall from an earlier chapter, the Ancient Greeks were very much concerned about the question of substance. At present, science tells us everything is made up of material atoms, and yet, philosophers still debate this scientific conclusion. It is not to say that atoms do not exist (although no one has actually seen one, which is another question about scientific realism), but rather a question of what is reality made up of, mind, matter, or a combination of both.
These questions lead to other questions regarding the nature of the human mind. Is it just the brain or does it have an immaterial component? What of the soul? All these questions will be considered in the following sections below.
POWERFUL IDEAS: THE NATURE OF SUBSTANCE
Materialism claims that all real objects are physical. Dualism claims that all real objects are either physical or nonphysical. Idealism claims that all real objects are nonphysical.
Berkeley and Idealism
Berkeley contends that the only things that are real are ideas. This view is known as idealism. All the objects we encounter in the world (which is an idea as well) are nonmaterial objects. As bizarre as this may at first sound, what you should be aware of is the fact that the only objects that we do have direct access to in our mind (or brain) are ideas.
We assume that our idea of objects in the world is tied to or come from these objects; some underlying physical substance, yet Berkeley is denying that we have any good reason to infer to this material substance. Berkeley employs a radical empiricism. He thought that we can only acquire knowledge from our experiences—from our per- ceptions. What is the nature of our perceptions? We assume that we perceive objects directly, yet in fact, what we are doing is experience an idea of the object, which has been constructed by our mind. Berkeley goes on to argue that “to exist is to be perceived.”
Berkeley contends that the only things that are real are ideas. All the objects we encounter in the world—which is an idea as well—are nonmaterial objects. As bizarre as this may at first sound, what you should be aware of is the fact that the only objects that we do have direct access to are our ideas. We assume that our idea of objects in the world are tied to or come from those objects (we think those ideas correspond to object in reality), some underlying physical substance, yet Berkeley is denying that we have any good reason to infer to is this material substance.
He may have a point. Consider a strawberry, for example. It has a certain color, shape, and weight; it has a particular texture, taste, and smell. These are all perceptions, ideas in your mind. If you take away the taste of the strawberry, take away its smell, its weight, its shape—what do you have left? Nothing. The strawberry is a bundle of those perceptions. Reality is a bundle of perceptions. In fact, Berkeley
believed, “to be is to be perceived”: esse est percipi. To take another example, consider an object, such as a desk in a room. What do you see besides color, shape, and exten- sion? If all we perceive are these things, and these qualities are ideas in the mind, why posit the existence of some other substance, matter that is unperceived? Berkeley goes on to make a distinction between immediate and mediate objects. Immediate objects are those we perceive directly, while mediate objects are those that we infer from our immediate perceptions.
In his view, matter or substance is something that we infer exists, but, in fact, we do not directly perceive. Yet what would the matter be like. What would the noumenal world (of Immanuel Kant (1724–1804, to be discussed later) be like? Is it not something that we can never know, yet we posit or assume that it exists? What Berkeley says is that we don’t need material substance to explain our experiences, and it is an unwarranted inference to draw because there is no reason to assume that our ideas that are of the phenomenal world correspond to a physical or material reality.
Berkeley goes on to mark a distinction in the type of minds that exist. He states that the world is composed of two things: ideas and minds. To be an idea, it must be perceived. Perceived by what? A mind. A mind is a perceiving thing. Finite minds can only perceive a limited number of ideas, so what happens to this room when no one is here to perceive it? Does it cease to exist? If that were the case, then how come it always reappears when some perceives it? Would it be the same room?
“If a tree were to fall on an island where there were no human beings would there be any sound?”
—The Chautauquan Magazine, 1883, in discussion of Berkeley’s metaphysics
Objects continue to endure, according to Berkeley, because there is one, Infinite Mind. His answer is that it the world continues to endure when we do not perceive it because it continues to be perceived by the infinite mind—God. God is an infinite mind that perceives all things. Ultimately, his entire philosophy can be boiled down to this one profound thought: to exist is to be an idea in the mind of God.
Powerful Thinkers: Immanuel Kant
One of the most influential philosophers in history, Immanuel Kant was born on April 22, 1724, in Königsberg, Prussia. He died there in 1804, never having strayed far from home and having lived a rela- tively quiet life. Yet, this quiet, lifelong bachelor’s works transformed philosophy forever.
Kant, in his monumental (and monumentally difficult) Critique of Pure Reason (1781) questioned the necessary conditions of experience, and he explored our possibilities of knowledge. He drew a distinction
between phenomena, the reality of appearances in our everyday life as we live it, and noumena, realities that exist independent of the human mind’s interpretation. Kant analyzed human experience and the way we organize it in terms of how that reality appears to us phe- nomenologically but also how it really is—a radically precise reas- sessment of a problem that goes back to Plato and Aristotle. Kant’s transcendental idealism explains how humans interpret the world by imposing structures and order on our perceptions of that world.
The human mind organizes experience based on categories we impose on experience. A priori propositions, such as 2 + 2 = 4, do not depend on experience. A posteriori propositions rely on experience for justification. For example, the proposition “Sally is hungry” relies on experience to show whether or not it is true.
Kant’s contributions to ethics, was as least as influential as his meta- physics. He began with his search for one ultimate principle to guide morals in 1785 Groundwork for the Metaphysics of Morals and contin- ued as he explained the rational justification for ethical judgments in his 1788 The Critique of Practical Reason. In 1790, The Critique of Judg- ment followed. For Kant, reason is the guiding principle of morals. This principle was his categorical imperative, a product of reason that states simply that you should act always as if according to a maxim that you would turn willingly into a universal law and also that you should always treat humanity—in your own person as well as that of others—as an end in itself and never as a means to an end. Kant’s ethics is discussed later in this book in the chapter on ethics.
Kant led a quiet life, and he stuck to his daily constitutional walking schedule so consistently that, so the story goes, housewives in Königs- berg would set their clocks by him. He began lecturing at the Univer- sity of Königsberg in 1755, finally got tenure as professor of logic and metaphysics in 1770, and soon afterwards wrote his first Critique.
The only controversy that came his way was when he wrote in his first his first Critique that “our age is an age of criticism, and to criticism all our beliefs must submit. Religion in all its holiness, and the state in its majesty, cannot exempt themselves from its tribunal without arous- ing suspicion against themselves.” Kant thought that the question of God could not be answered rationally, an insight not welcomed in conservative Prussia. The King of Prussia in 1792 forbade Kant to his lecture or writing on religion. He continued teaching in Königsberg until he retired in 1796, shortly after the publication of his visionary 1795 political work Perpetual Peace.
René Descartes and Substance Dualism
René Descartes (1596–1650) holds a view known as substance dualism or simply dualism. He maintains that reality is composed of two substances: mind and body. Mind is immaterial essence and body is material essence. All our thoughts and feelings are immaterial and exist in our mind, whereas our body exists in mate- rial space. He held that these two substances, one material and the other immaterial, interact with each other at some point in the body.
POWERFUL IDEAS: MIND OR BODY
René Descartes gives a number of arguments in an effort to try to prove the mind is not the body. Here are two such arguments:
I can doubt my body
1) I can doubt my body
2) I cannot doubt my mind
3) Since the mind and body have different properties, they must be dis- tinct objects
4) Therefore, my mind and body must be distinct things
From the above argument, Descartes concludes that the mind and body must be different objects. The problem with the above argument is that Descartes’ doubt is not an actual property of his body or of his mind—it
had no bearing on their existence or nonexistence. Perhaps seeing this flaw, he developed the following argument.
My mind and body have different properties
1) Body is physical
2) Mind is not physical
3) Since the mind and body have different properties, they must be distinct objects
4) Therefore, my mind and body must be distinct things
Physicality is an actual property of objects, so this argument avoids the flaws of the one discussed above. Unfortunately, the materialist will deny premise 2, whereas the idealist will deny the truth of premise 1—this leaves us where we started—unfortunately.
Other Views on the Interaction of Mind and Body
There are various other views on the nature and connection between the mind and the body. Identity thesis states that the mind and brain are identical. Dualism as noted above claims that the mind is mental and distinct from the brain is physical. Parallelism, which is also known as Epiphenomenalism, claims that what happens in the mind also happens at the same time in the brain, but there is no con- nection between the two things. Finally, Occasionalism, which is a version of epi- phenomenalism, states that although there is no connection between the mind and brain, magically or supernaturally God makes the two interact—so that when I think of something mentally, my body will follow my thoughts or vice versa.
John Searle—Supervenience
John Searle (b.1932) holds a version of dualism known as supervenience theory. At times, he claims it is dualism, and at other times, he claims, it is not. Most philoso- phers, against his objections, agree that his theory is a version of dualism but, let him call it what he wants. “The history of the philosophy of mind over the past hundred years,” Searle wrote, “has been in large part an attempt to get rid of the mental by showing that no mental phenomena exist over and above the physical.”
Whereas Descartes is willing to admit that the mental and physical are two dif- ferent substances (and hence this theory is technically known as substance dualism), Searle is unwilling to make that claims; though he thinks there is a men- tal and a physical, they may be two aspects of a single substance (not unlike Baruch Spinoza (1632–1677)) . He claims that consciousness (the mental thing going on in your head) comes from or supervenes upon the physical—in this case, the brain. The mental plays a causal role in explaining behavior and in our actions. The men- tal may not be immaterial, but it still exists.
This view, along with Berkeley’s idealism, and Descartes’ substance dualism can make sense of the notion that our thoughts, feelings, and intentions exist, but they are not the same as material objects.
Thomas Hobbes and David Armstrong
According to Thomas Hobbes (1588–1679), the only things that exist are “bodies [objects] in motion.” It is his view that thoughts, ideas, and feelings are physical entities explained by motions in the brain. Writing in the 1600s, he had no notion of neurons or any deep understanding of the human brain, yet he was certain all of these so- called mental properties would reduce to something physical taking place in the brain.
David Armstrong (1926–2014) argues for a strong version of materialism just as Thomas Hobbes does. Armstrong’s materialism holds that there is only one sub- stance, and it is material. Whatever consciousness is, it is material. The only things that exist are physical objects. As he says in his book, The Nature of Mind and Other Essays (1980), the mind “is not something behind the behavior of the body, it [is] simply part of that physical behavior.”
