Thomas Reid's Common Sense theory of Personal identity disagrees and critics Locke's and Hume’s theories, because of the emerged rationalism and empiricism. Firstly, Reid insists that personal identity establishes the relation between the things that exist in the different periods and presupposes continuance of existence. On the contrary, he objects the application of personal identity to pleasures, thoughts, feelings and perceptions. He supposes that one can place personality in the uninterrupted continuance of existence. According to Reid, memory puts evidence and knowledge about relations into practice. In fact, personal identity is precise and fixed and does not presuppose ambiguity. Consequently, Thomas Reid criticizes Locke and Hume on behalf of common sense.
On contrary, John Locke’s theory of personal identity relies on religion and morality. He believes that consciousness can be transferred from person to person. As a result, multiple people can act in the similar way. Locke states that “personal identity is founded all the right and justice of reward and punishment.” It means that his study of ethics intertwines with his religious beliefs. John Locke supposes a person as a container for the retention of memories, and describes this process as a basis for consciousness existence. A person is not born with the ability to memory development. Besides, memory is an indicator of personal identity. For John Locke, personal identity is related to the psychological continuity. His theory is contradictory since it relied upon consciousness and memory but does not take into consideration body and soul. For Reid, John Locke's theory of personal identity is absurd and wrong, since it does not presuppose identity as an in-born trait.
Furthermore, Thomas Reid criticizes theory of personal identity of David Hume because he does not address to the existence of a person. Besides, Reid states that there is no common sense in David Hume’s theory. Reid believes that for a person to have identity one should have perceptions and memories. For John Locke, memory serves as a foundation for the development of personal identity. For David Hume, perception is crucial. Moreover, he is not certain in his study saying that the question about personal identity remains unsolved. Hume believes that personal identity is a grammatical difficulty rather than philosophical.
Thomas Reid's study on the theory of personal identity relies upon the powers of passion, will, moral perception, reasoning, taste, imagination and memory. Thomas Reid does not give the definitions to such term as “identity” and “personality”. However, he believes that one cannot divide personality into the parts. For him, person is indivisible and is in the state of continues existence. Remembrance is the quality of the personality that reveals personal identity. Similarity and memory form a foundation for the development of identity. Thomas Reid does not believe in the perfection of the senses. However, he believes it to be the only explanation of personal identity.
Commonsense or Rationalistic theory differs from the Empiricism. Commonsense theory includes intuition or deduction thesis, the innate knowledge thesis and the innate concept thesis. Locke’s theory also presupposes the superiority and indispensability of the reason thesis. Empiricist theory rejects the existence of intuition and deduction thesis. Furthermore, commonsense theory is relevant in mathematics, while Empiricist theory is crucial for physical studies. One should mention that these theories should not conflict as they have different purposes. The crucial difference between empiricism and rationalism refer to basis of the knowledge. Empiricists collect knowledge and put it into practice. As to rationalists, they gain knowledge to achieve a sense of experience, independence and priory. They use intense and pure thinking to reach the superiority.
Rationalists use deduction to reach priori knowledge. Their conclusions are based on the valid arguments and intuited premises. For rationalists, it is crucial to make true conclusions. Empiricists use probability to check their knowledge. Logic, geometry and arithmetic are unimaginable without rational deduction; therefore, for rationalists these disciplines are the subjects of interests. Rationalists do not accept the slightest doubt. For empiricists, certain subjects depend on experience. Moreover, they believe that sense data is crucial for understanding the world and triggering thinking.
John Locke and David Hume belonged to empiricists. However, their empiricist theories differed. Locke believed that at birth the mind is a tabula rasa. The mind does not contain God-given or inborn ideas. However, it contains the capacity to reason and thinking. As to David Hume, he also supposed that mind was a tabula rasa. However, he objected to the idea that humans have a capacity to reason. Consequently, this is the crucial difference between John Locke's and David Hume's theories. David Hume also believed that a person could acquire everything through experience even the capacity to hold ideas and reason. Moreover, David Hume perceived sensory perception as a way of receiving experience from the physical world.
In conclusion, despite the fact that Reid criticized John Locke's and David Hume's empiricist theories defending a Commonsense theory, all theories contributed to the development of philosophy. The differences between John Locke and David Hume prove that both of them desired to find the truth. Combination of all these studies helps to understand how complex experience, memory and senses are in personality identity.
Physcalist theories state that non-physical mind and spirit do not exist. For physicalist philosophers, there is the only material or physical reality. One can explain everything through the physical terms. The advantages of physicalist theories are that they do not deal with mind-body interactions and their experience consists of unified objects. However, physicalism deals with many other issues. For example, they do not know how to explain mental terms if there is no mind. Physicalism also includes such notions as love, hope, intent, sensation, thought, idea, mental state and mind. Furthermore, each physicalist theory has its peculiarities that make it different. Physicalism regards everything as physical. As a result, pain in the left pinky will be the result of a poor functioning of neurons. For physicalists, world contains many items that are not just physical but also social, moral, psychological and biological.
Behaviorism, Identity Theory, Eliminativism and Functionalism are physicalist theories. All these studies show the relationship between mind and brain. Behaviorism supposes that every mental property is related to the behavior in a particular situation under certain conditions. The advantage of Behaviorism is that the falsity or truth can be empirically determined through mental terms. The disadvantage of Behaviorism is that it does not presuppose the inner experience and, therefore, a behaviorist definition creates a vicious circle and makes use of mental terms. Behaviorism describes consciousness as a function. For example, pain in the left pinky can provoke hurtful pain and tears. Looking at the injured pinky one can understand that it is the person is in pain. Consequently, this pain changes human behavior. This redness is a physical representation of the behavioral change. However, such behavior will be a foundation for defining the reason of redness. Behaviorism believes that mind is a disposition for human’s behavior. For behaviorists, the brain is the mechanism that enables behavior. Both brain and mind are immaterial.
Identity Theory or Reductive Materialism suggests that every mental concept refers to the nervous system and physical state of the brain. The advantage of this theory is that it turns mental states to brain activity or a single common denominator. The disadvantage of Identity Theory is that psychological terminology should specify neuroscientific descriptions. Identity Theory supposes soul as a language and denies it as a separate concept. Identity Theory regards mental states as brain states. To certain extent, Identity Theory sounds like a dualist, but it supposes the body as a structure of many parts. As a result, for the followers of Identity Theory, injured pinky through the neurons sends messages to brain. Such relation of the mind with brain will help to identify the consequences of the pain in a pinky. Identity Theory is an objection to Behaviorism. Identity Theory studies what regulates and causes behavior. For them, brain-mind identity is a scientific truth.
Eliminativism presupposes mental states as brain states. For the followers of this theory, mental states do not exist. As a result, mental language eliminates pain in redness. Eliminativism believes that mental term is a misleading and vague reference to certain physical activities of the nervous system and human brain. Mental terms are not relevant for them, they use only neurophysiologic terms. The advantage of Eliminativism is that it is not tied to the unscientific psychological vocabulary. The disadvantage of Eliminativism is that it does not understand that giving up the psychological vocabulary is impractical.
Functionalism refers every mental term to a complex mechanism or an internal state that has a functional role. The role is to set causal relations between bodily behavior, internal states and external conditions. Functionalism regards a mental state as a particular way of input processing. The result of a mental state is a culminated output. The advantage of functionalism is that it defines mental states as specific to the human brain. Functionalism opens the possibility of artificial intelligence. Functionalism is not biological. Consequently, it preserves psychology as a separate science. The disadvantage of functionalism is that it does not specifically define mental states. This is a problem, since not only brain can have mental states. Another disadvantage of functionalism is that it leaves out the qualitative nature of experiences. Functionalism is a philosophy that regards mental states as causes and effects. Functionalism is the objection to Identity Theory.
The Dualism, on the contrary, regards mental states as inner private thoughts. Dualism supposes the mind-body relationship the most natural and common bond. There are different types of dualism. Dualists believe that world is based on the distinct substances such as spirit and material.
In conclusion, physicalist theories vastly differ. The most practical ones are Behaviorism, Identity Theory, Eliminativism, and Functionalism. Behaviorism uses observation of human behavior, analyzing reactions on the emerged situations, to understand its relation to mental activity. Identity Theory studies physical states taking them from mental processes. Eliminativism relies upon mental states. Functionalism is interested in the role of the mental processes. One can underline the parallel between Identity Theory, Functionalism and Behaviorism as all these theories insist that mental phenomena are real processes. Eliminativism objects to the existence of the mind considering it as a useful fiction. Consequently, different philosophers will differently interpret pain in the left pinky and interpretation of redness. Finally, philosophy of mind would be poor without these theories.
JP Morelaand's “Contemporary Defense of Dualism” reveals problems with Physicalism as a worldview. His defense of dualism is related to his belief that there are distinctions between the mind and brain. Moreland underlines the parallel between dualism and physicalism. Dualism states that mind is separate from matter, while physicalism believes that matter is the only thing that exists in the universe. Consequently, Moreland accepts dualism and rejects physicalism. However, one can understand dualism through the metaphysics. Moreland defines two kinds of dualism: substance and property. The philosopher regards dualism to be the opponent of physicalism.
In “Contemporary Defense of Dualism”, Moreland distinguishes such problems with Physicalism as:
- Physicalism is false if theism is true. As a result, God is not physical.
- Numbers cannot be physical but abstract. If one does not believe in numbers, then one fails to believe in science and mathematics that provide knowledge.
- Person and animals have a non-physical value. Goodness or badness, values or non-physical property are moral laws.
- Laws, concepts and theories of logic are non-physical, and are true.
- Universals (hardness, redness) are non-physical matters.
It is evident that Moreland does not support physicalism and views it as inadequate and illogic. Moreover, he does not interpret the universals through physics. Physicalism considers everything what exists as nothing else but a spatio-temporal system.
In his “Contemporary Defense of Dualism”, Moreland reveals the
problems with Mind/Body Physicalism. Primarily he studies the nature of identity and distinctiveness of physical and mental properties. Consequently, he distinguishes the following issues:
- Law of body and identity-mind have different properties, as a result they are different. Physicalism does not include properties for the mental events.
- Mental processes are private (pictures, memories and feelings). They are characterized by incorrigibility and private access.
- Mental states cannot be mistaken with thoughts. For example, a brain surgeon cannot get to know mental life of a patient or penetrate into his/her mind.
- The experience of every person is subjective. Metaphorical properties are subjective.
- The aboutness of a mind.
- Personal identity is related to the separation of the soul from the body.
One can distinguish such Paul Churchland's arguments against Mind-Body Dualism:
- All known mental phenomena are neutrally dependent.
- People do not know anything about mind. As a result, it is difficult to talk about matter and its relation to consciousness.
- Materialism provokes entities.
Paul Churchland is not completely categorical about dualism. However, his arguments against dualism are evident. Firstly, one should not give any weight to dualism when materialism can replace it. Dualism cannot explain everything. Dualism is not a simple theory as it is controversial and disregards other things. Moreover, the “mind staff” is unknown for the dualists. Materialism has bigger explanatory power than dualism. “The dualist can admit that the brain plays a major role in the administration of both perception and behavior.” Dualism is too complicated and one cannot use it for the explanation of everything using one theoretical point of view. The adoption of introspection by dualists is uncertain and unreliable. One should apply other forms of observations.
Moreland would respond to the suggestions made by Paul Churchland, since he believed in the relevance and significance of dualism. Mental states are related to the physical ones. For example, a feeling of pain is a mental state. However, sticking oneself with a pin is a physical state and it is related to the mental state. Another example is raising a hand during the voting. Voting is a mental state, and raising a hand is a physical state. These examples prove that dualism clearly explains the relation between the mind and the body. Moreland applied his theory regarding the physical state in the vocabulary of chemistry and physics. It means that rationalism is also present in his philosophical studies. For Moreland, evolution does not explain thoughts and soul.
Nagel also responded to the suggestion of Paul Churchland. He wrote, “If we can reason, it is because our thoughts can obey the order of the logical relations among propositions.” It means that this philosopher relies upon reason and logical thinking. As a result, his response would be against dualism and its explanation of the body-mind relations. Moreover, he involves religion for the explanations of human behavior. Consequently, his philosophical vision contradicts dualism. Naturalism and religion are the main theories he uses for the explanation of the human behavior. Church and common sense principles are form his opinion of dualism.
As to David Chalmers, he was the supporter of dualism. However, his dualism is naturalistic. One can say that his response will be supportive of Moreland and Nagel. He does not suppose mental experience a dualistic one. As a result, his theories differ from Moreland's.
In conclusion, one should say that JP Moreland's “Contemporary Defense of Dualism” has the right for existence and application as other philosophical studies. The contradictions and debates between philosophers only prove their love to philosophy and desire to defend their opinion. One can say that dualism is a valuable philosophy as it has turned into the naturalistic dualism promoting the religious beliefs.