David Hume was an 18th-century Scottish philosopher who is widely regarded as one of the most influential figures in the history of Western philosophy. His theory of knowledge, which is often referred to as empiricism, holds that all knowledge is derived from sense experience.
Hume believed that knowledge is not innate, but rather it is gained through observation and experience. He argued that the mind is a blank slate at birth, and all ideas and concepts are acquired through sensory experience. This is in contrast to the rationalist philosophers, who believed that certain ideas were innate and could be deduced through reason alone.
Hume believed that there are two types of knowledge: matters of fact and relations of ideas. Matters of fact are things that can be observed in the world, such as the color of a flower or the sound of a bird. Relations of ideas, on the other hand, are concepts that are true by definition, such as mathematical truths or logical propositions.
According to Hume, all knowledge of matters of fact is based on causation. We infer that one event will follow another based on our past experience of similar events. For example, we know that the sun will rise tomorrow because it has risen every day that we can remember. However, Hume argued that there is no necessary connection between cause and effect. We cannot know with certainty that the sun will rise tomorrow, even though it is likely to do so based on past experience.
Hume’s theory of knowledge had a profound influence on later philosophers, particularly Immanuel Kant, who sought to reconcile Hume’s empiricism with rationalism. Kant argued that although all knowledge is ultimately based on experience, there are certain categories of thought that are necessary for us to make sense of that experience. For example, we cannot have knowledge of causation without the concept of cause and effect.
Hume’s theory of knowledge, also known as empiricism, is an influential philosophical framework that posits that all knowledge arises from sensory experience. While Hume’s theory offers a unique perspective on the nature of knowledge, it has also been subject to numerous criticisms.
One major critique of Hume’s theory is that it fails to account for the role of intuition in knowledge acquisition. While Hume argues that all ideas and concepts are derived from sensory experience, it is difficult to explain how humans acquire knowledge of abstract concepts such as justice or beauty. Additionally, Hume’s framework does not account for the role of innate knowledge, such as our innate ability to recognize faces or understand language. These criticisms suggest that there may be other ways of acquiring knowledge beyond sensory experience alone.
Another criticism of Hume’s theory is that it is overly skeptical about the possibility of knowledge. Hume argues that our knowledge of the world is based on past experiences and that we can never be certain of the future. While this is true to a certain extent, it can also lead to a radical skepticism that undermines our ability to make decisions or engage in any meaningful action. This skepticism can lead to a kind of paralysis that makes it difficult to function in the world.
Hume’s theory also has been criticized for its emphasis on causation. Hume argues that all knowledge of matters of fact is based on causation, but this leads to a problem of induction. We can never know with certainty that a future event will follow a past one, even if they have always been observed together. This undermines our ability to make predictions about the future and can make it difficult to rely on past experiences to inform our decisions.
Finally, Hume’s theory has been criticized for its neglect of the role of reason in knowledge acquisition. Hume argues that all ideas and concepts are derived from sensory experience, but this seems to neglect the role of reason in interpreting and understanding that experience. Reason is necessary for making sense of the information that we receive through our senses and for making inferences about the world. Hume’s framework, however, seems to downplay the importance of reason in knowledge acquisition.
In conclusion, while Hume’s theory of knowledge offers a unique perspective on the nature of knowledge, it has also been subject to numerous criticisms. These criticisms suggest that Hume’s framework may be incomplete or overly skeptical in certain respects. Nonetheless, Hume’s ideas continue to be influential in contemporary philosophical discussions, and his work remains an important part of the philosophical canon.
An Essay Concerning Human Understanding is a philosophical work by the English philosopher John Locke, published in 1689. The book is considered one of the foundational texts of modern Western philosophy and is widely regarded as a masterpiece of philosophical writing. It presents a comprehensive account of the nature and limits of human knowledge and understanding, as well as the role of experience and reason in human cognition.
The main argument of the Essay Concerning Human Understanding is that all knowledge is derived from experience. Locke rejects the idea of innate ideas or knowledge, arguing that the mind at birth is a blank slate, or tabula rasa. He contends that all knowledge and ideas come from sensory experience, and that our understanding of the world is based on the associations and patterns that we observe in the natural world.
Locke divides human knowledge into two categories: intuitive knowledge and demonstrative knowledge. Intuitive knowledge is knowledge that is self-evident, such as the mathematical truths that are immediately apparent to us. Demonstrative knowledge is knowledge that is derived through reasoning and evidence, such as scientific or historical knowledge.
Locke also distinguishes between primary and secondary qualities of objects. Primary qualities are those that are inherent in the object itself, such as shape, size, and motion. Secondary qualities are those that are perceived by the observer, such as color, taste, and smell. Locke argues that our perception of secondary qualities is not a direct perception of the object itself, but rather a product of our own sensory experience.
The Essay Concerning Human Understanding also addresses the limits of human knowledge. Locke argues that our knowledge is limited by the extent of our experience, and that there are many things that we cannot know with certainty. He acknowledges the existence of a realm of uncertainty and ambiguity, which he calls the realm of opinion. In this realm, we must rely on probability and judgment rather than certainty.
One of the most important aspects of the Essay Concerning Human Understanding is Locke’s theory of language. He argues that language is essential to human thought and knowledge, and that words are the vehicles by which we convey our ideas and communicate with one another. Locke contends that words are not simply arbitrary symbols, but rather are connected to the ideas and experiences that they represent.
Locke’s theory of language also includes a critique of the use of language in philosophical discourse. He argues that many philosophical debates are based on the misuse of language, and that many of the disputes between philosophers are the result of different uses of the same words. He advocates for a more precise and rigorous use of language in philosophical discourse, and argues that this would lead to greater clarity and understanding.
The Essay Concerning Human Understanding has had a profound impact on the development of modern philosophy, particularly in the areas of epistemology and metaphysics. Locke’s rejection of innate ideas and his emphasis on the role of experience and reason in human knowledge have been influential in shaping modern empiricism and rationalism.
Locke’s work has also had an impact on political philosophy. He argues that all individuals are entitled to certain natural rights, including the right to life, liberty, and property. These ideas were influential in the development of the concept of natural rights and the modern theory of liberal democracy.
In conclusion, An Essay Concerning Human Understanding is a monumental work of philosophy that presents a comprehensive account of human knowledge and understanding. Locke’s rejection of innate ideas and his emphasis on the role of experience and reason in human cognition have had a profound impact on modern philosophy and have helped to shape our understanding of the nature and limits of human knowledge. The Essay Concerning Human Understanding is a must-read for anyone interested in philosophy, epistemology, and the nature of human thought and understanding.
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Hume’s theory of knowledge was very much influenced by both Newton’s scientific view of the world and John Locke’s theory of knowledge.
On the one hand, Hume appropriated Newton’s view of the universe in his philosophy. For Hume, following Newton, the universe has its own nature and dynamics which is intelligible by the human mind. What the human mind can hope for, therefore, is to simply describe how the universe works through systematization or the act of putting together the series of events into a single whole.
On the other hand, following Lock, Hume believes that all forms of knowledge come from experience. This explains why Hume rejects the rationalist position that there is a supersensible or transcendent source of knowledge. Yet, Hume’s conclusion is more skeptical than Locke’s. As is well known, Locke argues that knowledge is limited only to things that can be experienced. As a matter of fact, Locke says that reason has no room to operate when it comes to ideas that cannot be experienced, such as freedom and immortality of the soul. For Hume, we need to suspend our judgment when we delve into subjects remote from the affairs of common life and experience. Hume’s position is famously known as “moderate skepticism”.
Key Concepts of Hume’s Theory of Knowledge
On the Nature of Ideas. As Locke argues, ideas come from sensation and reflection. Hume calls it impression. Hence, when we say “impression” in Hume, this includes both sensation and reflection in Locke. And for Hume, ideas come from impression.
Following Locke, Hume claims that out of simple ideas the mind forms compound or complex ideas. For example, out of the simple ideas such as “horse” and “horn”, the mind can come up with a compound idea of a “unicorn”.
According to Hume, ideas that do not represent something in reality is an abstract idea and, therefore, meaningless. The idea of a “unicorn” is an example of an abstract idea because in the first place, there is no unicorn in reality.
Association of Ideas. According to Hume, there is a multiplicity of ideas, yet all these ideas are linked together forming a coherent whole. For Hume, this is made possible by the “laws of association”.
There are three laws of association according to Hume, namely:
1) resemblance,
2) contiguity in time or place, and
3) cause and effect.
In the law of resemblance, Hume says that the idea of one object tends to call to mind ideas of resembling objects. For example, the idea of “man” resembles the ideas of “thinking”, “corporeal”, “mutable”, and “finite”.
In the law of contiguity in time and place, Hume says that when we think, for example, of “Hitler”, we tend to think of the “Holocaust”, “concentration camp”, and “Nazism”.
In the law of cause and effect, Hume says that when we think of, for example, the idea of a “fresh egg falling to the ground”, it calls to mind the idea of a “splattered mess”.
It is important to note that Hume puts more emphasis on the third law of cause and effect. In fact, the law of cause and effect is one of the most important concepts in Hume’s theory of knowledge. This explains why after talking about the law of cause and effect, Hume proceeds to the discussion on “perception” and “reasoning”.
Hume on Perception and Reasoning
Human understanding, according to Hume, is furnished with…
1) the faculty of perception and
2) the faculty of reason.
On the one hand, the object of perception are impressions or ideas. On the other hand, the object of reason are propositions.
According to Hume, propositions are either
1) a priori statements about relations of ideas or
2) empirical statements about matters of fact and real existence.
Relations of ideas, according to Hume, can be known intuitively or demonstratively.
For example, the proposition “All triangles have three angles” is an example of a proposition that can be known intuitively.
The proposition “The sum total of all three angles in a right triangle is equal to 180 degrees” is an example of a proposition that can be known demonstratively.
It is important to note that in relations of ideas, the truth can be established without empirical evidence. In fact, in both examples above, we don’t need to resort to experience before we can truly say that all triangles have three angles or, indeed, the sum total of all three angles in a right triangle is equal to 180 degrees. Through mental processes alone, we can truly say that indeed the propositions above are absolutely true.
Matters of fact, according to Hume, are propositions whose truth can be discovered through experience alone. Consider, for example, the proposition “Sugar is sweet”. Obviously, one cannot really say that indeed sugar is sweet if one has not tasted it. Hence, we can never come to know that sugar is sweet without resorting to experience.
It is must be noted that it is “matters of fact” that concerns Hume. In fact, Hume’s theory of knowledge centers on the idea of “matters of fact”.
Hume asks: “What is the nature of the empirical evidence which assures us of any real existence of matters of fact?”
According to Hume, we are assured of some facts by the present testimony of our senses or by the records of our memory. In other words, for Hume, we know that facts exist in reality simply because we experience them. This explains why Hume was an empiricist.
But the question is by what means do we get beyond such facts? In other words, how can we be sure that such facts exist in reality? This is the central question in Hume’s theory of knowledge, which he developed in his famous work Enquiry Concerning Human Understanding.
So, again, by what means do we get beyond such facts?
According to Hume, it is by means of the relation of cause and effect that we are enabled to make, more or less reasonable, predictions and conjectures that go beyond the data of perception and memory.
But how do we arrive at the knowledge of cause and effect?
The answer, for Hume, is not reasoning a priori (as the rationalists would have us believe) but entirely from experience. Again, for Hume, our knowledge of cause and effect relation remains limited to experience. Of course, the mind steps beyond experience and engage in reasoning. But for Hume, this kind of reasoning is not supported by any argument or process of understanding through relations of ideas or through reasoning a priori. This kind of reasoning, for Hume, is supported by habit or custom.
Now, it must be noted that for the rationalists, cause and effect relation falls under a priori reasoning. In other words, for the rationalists, there is a necessary connection between cause and effect. For example, if it is raining at the moment, then reason tells us that the road must be wet. However, for Hume, in reality there is no necessary connection between two events, between cause and effect. The idea of a necessary connection is produced in the mind not through reason a priori, but through habit or custom. Hence, Hume did not reject the idea of “connection” wholesale. He only rejects the idea of connection employed in metaphysical reasoning, that is, the a priori reasoning in rationalism.
Again, for Hume, there is (necessary) connection only through experience (in common life and practice) which is based on habit.
Hence, the only evidence assuring us of any real existence and matters of fact is experience, that is,
1) the present testimony of our senses,
2) the records of our memory, and
3) the causal (experiential) reasoning based on the empirically
observed regularities of past experience. As Hume writes:
“Knowledge of reality can only be derived from a careful observation of the ‘constant conjunction’ between contingent events. Where such constant conjunction is observed, we are inclined to attribute a causal relationship between events designated as ’cause and effect’.” See David West, An Introduction to Continental Philosophy (Cambridge, UK: Polity Press, 1986), p. 15.
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Introductory Notes on Spinoza’s Theory of Knowledge
One can meaningfully make sense of Spinoza’s theory of knowledge if it is understood within the context of Descartes’ theory of knowledge.
Like Descartes, Spinoza was a rationalist. In fact, Descartes was a great influence on Spinoza. However, Descartes and Spinoza differ on their understanding of thought and extension. We learned from Cartesian dualism that thought and extension are the essence of two causally interacting substances. Hence, in Cartesian philosophy, thought (or mind) and extension are two independent substances. In contrast to this view, Spinoza believes that thought and extension are parallel aspects of one and the same substance. Hence, in Spinoza, there is no dualism; thought and extension are not existing independently from each other.
It is also important to note that The Ethics, which is Spinoza’s magnum opus, provides the key to understanding the entire system of Spinoza’s philosophy. The ultimate aim of the book, which is also the ultimate aim of his philosophy, is human blessedness, a blessedness that is inseparable from “knowledge of the union existing between mind and the whole of nature”. As we can see later, for Spinoza, the greatest goal of human life is to understand one’s place in the structure of the universe as a natural expression of the essence of God. Thus, human blessedness for Spinoza means having adequate knowledge of the motives of what we do, which in turn leads us to engage in deliberate action. In understanding Spinoza’s philosophical system, we should be guided, therefore, by what his philosophy ultimately aims to achieve.
Another important introductory concept that will help us understand Spinoza’s theory of knowledge is the vacuum argument, which is implied in Descartes’ theory of knowledge. For a detailed discussion on Descartes’ theory of knowledge, see “Descartes’s Theory of Knowledge”.
Now, for both Descartes and Spinoza, the vacuum remains a “something”, with size and shape, though it lacks mass, solidity, impenetrability, and the like. For Descartes, an empty space or vacuum remains something real, though it contains nothing perceptible in it. Hence, an empty space or vacuum is just a particularly thin region of a single reality, that is, RES EXTENSA or extended substance. And it must be noted that for Descartes, there is only one extended substance, and it is SPACE.
Spinoza developed this Cartesian thought on empty space. For Spinoza, all physical objects (that is, things) are simply qualities (or modes) of one substance, namely, the whole of SPACE. Thus, for Spinoza, the difference between matter and empty space is just the difference between thick and thin regions of SPACE.
Descartes and Spinoza share the same view that there is only one material reality, that is, EXTENDED SUBSTANCE or SPACE. But they differ on their views of a thinking substance, or RES COGITANS. Descartes thought that there are many spiritual realities (that is, things that have minds) of THINKING SUBSTANCES or RES COGITANS. Spinoza rejects this position. Spinoza argues that there is only one substance, and that there is only one thinking substance, which is identical with material substance. Thus, as we can see later, for Spinoza, reality is ONE. For Spinoza, reality equals substance and all its modes. And for Spinoza, substance and all its modes equal God, or nature (Deus, sive Natura). The discussion that follows briefly sketches the key concepts of Spinoza’s theory of knowledge.
Key Concepts of Spinoza’s Theory of Knowledge
Substance, Modes, and Attributes
Spinoza borrowed the Cartesian notions of substance, modes, and attributes and appropriated them in his philosophy.
Spinoza modified the Aristotelian definition of substance as something or anything that exists in itself. Spinoza agrees with Aristotle that a substance is that which exists in itself. But Spinoza added that “the conception of which does not require the conception of another thing from which it is to be formed” (Ethics, 1d3). In other words, substance for Spinoza is conceived through itself. For this reason, a tree, understood in the Aristotelian sense as substance, is not really a substance for Spinoza because although it exists in itself, it cannot be conceived through itself. A tree (and other material things) exists in time and space, but it is conceived or explained in terms of the laws governing spatial reality. For Spinoza, therefore, there is only one substance and that is Nature.
Nature for Spinoza is the totality of modes. Spinoza understands modes as the sum total of all the qualities and states of a substance, and which are knowable only in terms of an attribute. According to Spinoza, attribute refers to that which the intellect perceives of substance as constituting its essence, namely, thought and extension.
Mind and Body
For Spinoza, modes include not only qualities (for example, hardness, color, and the like), but also things or matter (for example, a tree or a person) in general. Here, Spinoza includes not only physical matter or things but also mental and psychological predicates like thought and feeling.
But unlike Descartes, Spinoza argues that there is no dualism between thought and extension. Rather, thought and extension are two attributes of one and the same underlying reality. Thus, for Spinoza, all modes (that is, everything in nature) fall under attributes (thought and extension). Thus, for Spinoza, an extended substance is identical with a thinking substance. Indeed, for Spinoza, “all extended things are also thinking things”.
Panpsychism
As we can see, Spinoza’s view of Nature falls under Panpsychism, the thesis that all extended things are also thinking things. Panpsychism also holds the belief that everything has a soul. As an adherent of Panpsychism, Spinoza argues all living things also think. A tree, for example, is a thinking thing for Spinoza.
But it must be noted that the term “thinking” for Spinoza is not only limited to mental attributes. For Spinoza, thinking also includes “subconscious desires and perceptions”. For this reason, plants and animals can also be categorized as “thinking things”, but they do not have conscious mental life as humans do. This explains why Spinoza rejects Descartes’ view that it is humans alone who think. Like Hobbes who argues that the mind could just be matter in motion, Spinoza believes that the mind (of humans) differs only in terms of “degree” but not in “kind” from the rest of nature.
Deus, sive Natura (God, or Nature)
The concept of God as Nature is the key to understanding Spinoza’s notion of “reality as one”.
As is well known, Spinoza identified God with Nature. Thus, for Spinoza, God in Himself is identical with God’s creation. As we can see, Spinoza is a Pantheist. Pantheism is a form of naturalism that views Nature as God, where God means the infinite, unitary, and self-existent cause of all existence.
As a Pantheist, Spinoza believes that everything found in Nature is simply and extension of God inasmuch as everything in Nature is part of God.
It must be noted, however, that Spinoza’s view of Nature is a deterministic system, which means that every event taking place within it is caused by another, antecedent event within the system. And because this cause-effect relationship happens within the system, an appeal to a final cause is not possible. Thus, Spinoza tried to transfer the religious attitude of worshipful awe and humble love from “God, the personal creator of Nature” to “God, the impersonal system of Nature itself”.
It is important to note that Spinoza used the term “infinite cause of the universe” rather than “final cause of the universe” in order to show that in the deterministic system of Nature, there is no God as final cause of everything. This is simply because God is Nature in itself. And for Spinoza, cause and effect is simply part of God or Nature, and since this event (that is, cause-effect) happens within Nature, then, again, there is no final cause.
Spinoza’s Moral Teachings
According to Spinoza, the greatest good of human life is to understand one’s place in the structure of the universe as a natural expression of the essence of God. This is what Spinoza calls human blessedness, which is, as already mentioned, the goal of Spinoza’s philosophy.
Human blessedness, for Spinoza, is having adequate knowledge of the motives of what we do, and which leads us to engage in deliberate action. In this way, actions are considered morally good. Again, this only happens when we recognize our place within the grander scheme of reality as a whole. The reason behind this is that if we know that Nature is God, then any action that is harmful to Nature (to everything, especially humans) is an attack on God.
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René Descartes’s theory of knowledge was first articulated in his famous work The Discourse on the Method, but was fully developed in his later famous work Meditations on First Philosophy.
Descartes was considered the Father of Modern Philosophy. He was also the first major figure in the philosophical movement in the modern period known as rationalism. Rationalism can be viewed from two vantage points, namely, as a method and as a doctrine.
On the one hand, rationalism can be viewed as a method of understanding the world based on the use of reason as the means to attain knowledge. On the other hand, rationalism can be viewed as a doctrine in epistemology which regards reason as the chief source and test knowledge.
Key Concepts in Descartes’s Theory of Knowledge
One of the key concepts that we need to remember in Descartes’ theory of knowledge is the idea that sense perception is unreliable. As a matter of fact, Descartes rejects the idea that sense perception conveys accurate information. Thus, it could be said that one of the goals of Descartes is to distinguish what is true from what is false. In doing so, Descartes employs the famous methodic doubt where he doubts everything believed to be true until certainty is attained. In this process, ideas are put in rigorous test in determining its certainty. As is well known, the methodic doubt is the central concept of Descartes’ first published work titled The Discourse on the Method.
The second key concept in Descartes’ theory of knowledge is the idea that reason is the essence of humanity. For Descartes, the very act of thinking offers a proof of individual human existence. Hence, thought and reason, according to Descartes, must be the essence of humanity. In fact, as Descartes argues, a human person would still be human even without hands or hair as long as he has reason, that is, the ability to think creatively. And because only humans have the ability to think, animals, therefore, don’t think. According to Descartes, animals act based on their instinct.
The third key concept that we need to remember in Descartes’ theory of knowledge is the claim that knowledge can attained. As we can see, Descartes emphasized this point as a response to the claims of the skeptics that we cannot attain knowledge. For Descartes, reason is a native gift. And Descartes believes that true knowledge can be attained though the methodical application of reason.
Descartes’ Discourse on the Method
The Discourse on the Method is Descartes’ first published work. It was written in Latin, rather than in French. It must be noted that during the time of Descartes, Latin was still the accepted language of scholarship. Hence, the attempt to write in language other than Latin during this time was revolutionary.
The Discourse on the Method is also Descartes’ attempt to explain his method of reasoning, which contains six (6) parts. In what follows, I will briefly sketch the key concepts of each part.
Part I: On Good Sense
One of the main points of Part I of Descartes’ Discourse on the Method is idea that people possess “good sense”. Descartes understands good sense as the ability to distinguish truth from fiction.
According to Descartes, because people possess good sense, it is therefore not the lack of ability to think that obstructs people from attaining truth, but their failure to follow the correct path of reasoning. Thus, as Descartes argues, it is the use of a method that can elevate an average mind above the rest. In fact, Descartes considers himself as an average thinker improved by the use of his method.
Part II: On Methodic Doubt
It is in Part II of the Discourse on the Method that Descartes lays down the rules which he believes is the way to certainty. As is well known, this method was famously known as the “methodic doubt”. This method involves four (4) steps, namely:
To never believe in anything unless she can prove it herself.
To reduce every problem to its simplest parts.
To always be orderly in one’s thoughts and proceed from the simplest part to the most difficult.
To always, when solving a problem, create a long chain of reasoning and leave nothing out.
Part III: Descartes’ Moral Code
It is in Part III that Descartes puts forth a provisional moral code to live by, namely:
To obey the rules and customs of one’s country and religion and never take on extreme opinion.
To be decisive and stick with one’s decisions, even if some doubts linger.
To try to change one’s self, and not the world.
To examine all professions in the world and try to figure out what the best one is.
Part IV: Descartes’ Arguments for God’s Existence
In Part IV of the Discourse on the Method, Descartes offers his argument for God’s existence. Contemplating the nature of dreams and the unreliability of the sense, Descartes becomes aware of his own processes of thinking. Descartes eventually realizes that “thinking” is a proof of his existence.
Now, because Descartes has the ability to doubt, he believes that he is imperfect. But because someone has the ability to conceive of perfection, then, for Descartes, it follows that something or someone perfect must exist outside of him, namely, God. Therefore, God exists. And for Descartes, all things in the world, including clear and distinct ideas, comes from God.
Part V: On the Immortality of the Soul
One of the highlights of Part V is Descartes’ discussion on the immortality of the soul.
Descartes believes that the soul has a life outside of the body. Thus, for Descartes, the soul could not perish. The soul, therefore, is immortal. Descartes, however, did not provide any proofs as to the existence of the soul outside the body.
It must be noted, however, that Descartes equates the soul with mind. Hence, the soul for Descartes can be understood as reason, that is, the rational soul.
Part VI: On Physics
Part VI is the concluding part of the Discourse on the Method. It touches on the possible conflict between the Church and Descartes’ view on physical science.
It must be noted that Descartes supports Galileo’s heliocentrism, and because Galileo was excommunicated by the Church, Descartes was very careful in the end so as not to experience Galileo’s fate.
It is also in Part VI that Descartes shows the practical application of his method in mathematics and the physical sciences.
The Meditations on First Philosophy is Descartes’ most famous work. Though it is usually known as the Meditations, the full title of the work is Meditations on First Philosophy in which the Existence of God and the Distinction of the Soul from the Body are Demonstrated.
The Meditations on First Philosophy or, simply, the Meditations, is prefaced by a letter to the wisest and most distinguished men, the dean and doctors of the Faculty of Theology of the then University of Paris. Descartes’ intention of doing this is obvious. As we may already know, it had been just 8 years since the condemnation of Galileo. As is well known, Descartes allied himself with the basic outlook of Galileo, especially on the argument that the sun is the center of the universe (heliocentrism) instead of the earth (geocentrism).
Because the Faculty of Theology at the University of Paris had been so influential for centuries, Descartes seemed to believe that if he could secure the approval of the Faculty of Theory at the University of Paris, then he may be able to escape Galileo’s fate.
As we can see, the Meditations on First Philosophy gained approval from the Faculty of Theology at the University of Paris; however, after 22 years, the Roman Catholic Church placed it on the Index Librorum Prohibitorum (Index of Forbidden Books). As is well known, the Index Librorum Prohibitorum is a list of books that were once forbidden by the Roman Catholic Church because these books were considered as dangerous to the Catholic faith and morals of the Catholic Church.
Just as the Discourse on the Method, which is Descartes’ first published work, the Meditations on First Philosophy is also composed of 6 parts. In what follows, I will briefly sketch the key concepts of each part.
Meditations on First Philosophy (Meditation I): On What Can Be Called into Doubt
In the first meditation, Descartes reiterates materials from his previous work titled the Discourse on the Method. For example, in the first meditation, Descartes employs again the concept of “methodic doubt” that he first introduced in the Discourse.
As is well known, the methodic doubt seeks to doubt everything believed to be true in order to determine which beliefs one could be certain as true. The methodic doubt, therefore, necessarily leads to the discovery of truth. How is it possible?
For Descartes, the fact that he is doubting shows the certainty of the existence of a being that doubts. It goes to show that if, for example, I am doubting, then I must be thinking. And if I am thinking, then I must exist. Needless to say, the existence of the thinker necessarily precedes the act of thinking. Therefore, Descartes sets out to prove, using only reason, that some truths are beyond doubt. Indeed, this is the basis of the famous Cartesian phrase “Cogito ergo sum” or “I think, therefore, I am”.
However, Descartes admits that he cannot be sure that God is not playing some tricks on him. The idea here is that there might be a powerful demon that tricks him and created some illusions in the physical world to deceive him. This is what we call in Cartesian philosophy the “demon problem”. But because Descartes believes that God is good, he is convinced that God would not deliberately deceive him. Therefore, the I is certain of itself which, as we can see, proves the point that indeed the human mind can attain truth.
Meditations on First Philosophy (Meditation II): On the Nature of the Human Mind, which is Better Known than the Body
Most of meditation II is devoted to discovering whether there is anything that Descartes can be certain about. It is important to remember that in the first meditation, Descartes talked about things that can be doubted and employed the methodic doubt in discovering the truth. In meditation II, Descartes continues to demonstrate how certainty can be attained.
As already explained, Descartes is convinced that he can be certain that he exists because if he doubts, there must be a thinking mind that does the doubting. From here, Descartes proceeds to addressing the question “What is this ‘I’ that does the thinking?”.
Descartes’ answer is that this mind is purely a thinking thing. In other words, for Descartes, the mind is nothing but a thing that thinks.
Descartes, however, concedes that though what he perceives with his senses may be false, he cannot deny that he is perceiving. Thus, for Descartes, the human mind is capable of both thought and perception. In other words, for Descartes, sensation or perception belongs to the mind. As a matter of fact, sensation is one of the functions of the mind (the other is thinking). Descartes uses the analogy of the wax to prove his point.
As we can see, a solid wax and melted wax are the same wax. For some thinkers, such as the empiricists, it is the senses that distinguishes a solid wax from a melted wax. For Descartes, however, the ability to distinguish a solid wax from a melted wax is not the function of the senses but of thought. In other words, it is “thought” or the “reasoning mind” that makes the judgment that a solid wax and melted wax are the same wax.
For Descartes, therefore, because the senses can be deceived, physical objects, including bodies, are properly perceived only by the intellect. Indeed, for Descartes, the mind is the only thing that one can be certain of.
Meditations on First Philosophy (Meditation III): On God’s Existence
One of the central points in meditation III is Descartes’ attempt to prove the existence of God. Here, Descartes argues that the idea of God is necessarily true because it is grasped with clarity and distinctness. As we can see, Descartes’ ontological proofs of God’s existence is based on the notion of “clear and distinct” ideas. On the one hand, an idea is clear for Descartes if one cannot help taking notice of it, such as toothache. On the other hand, an idea is distinct if it cannot be confused with anything else. For example, the idea of a table cannot be confused with the idea of a chair.
Now, in proving that the idea of God is clear and distinct, Descartes introduces his theory of ideas. According to Descartes, there are three types of ideas, namely:
1) innate,
2) adventitious, and
3) fictitious.
According to Descartes, innate ideas are ideas within us that do not come from experience. Take, for example, the mathematical proposition “2 x 2 = 4”, or the statement “All triangles have three angles”. As we can see, we do not resort to experience in order to prove the point that twice two is always four or the fact that there is not at least one triangle that does not have three angles. Through mental processes alone, we can logically conclude that indeed twice two is always four, or all triangles have three angles.
It is important to note that for Descartes, innate ideas are not present in us the moment we are born. Hence, babies and mentally defective adults do not have innate ideas. This is because for Descartes, innate ideas are proper only to, or can only be possessed by, a rationally developed mind. What is there the moment we are born is the possibility for our mind to become rationally developed, which in turn enables us to possess innate ideas.
Adventitious ideas are ideas that are based on our experience with the world and the things around it. For example, we may say “Sugar is sweet”. Of course, as Descartes would have us believe, we can only be sure that the statement “Sugar is sweet” is true if we have experienced it, that is, if we have personally tasted it.
Fictitious ideas are those ideas that are the product of our imagination. Consider, for example, the idea of a unicorn. Of course, there is no unicorn in reality (hence, fictitious), but we can come up with this idea by combining the idea of a horse and a horn. So, if we imagine a horse with a single, large, pointed, spiraling horn projecting from its forehead, then we have arrived at the idea of a unicorn.
Now, what is the point of Descartes in introducing these three types of ideas in relation to his concept of God as innate?
According to Descartes, our idea of God is innate and is placed in us by God. And because innate ideas as self-evident, clear, and distinct, then our idea of God is also self-evident, clear, and distinct. Therefore, God necessarily exists.
However, Descartes’ ontological proof for God’s existence goes like this: “If something exists, then it must be caused by something else. The only possible ultimate cause is an infinite, perfect being. But because God is the only infinite and perfect being, therefore, God exists.”
Meditations on First Philosophy (Meditation IV): On Truth and Falsity
In the third meditation, Descartes was certain that God is perfectly good. However, if God is perfectly good, how then is error or falsity possible?
According to Descartes, everything that God created is perfect. But God created humans as finite beings whose finitude still leaves room for error. Descartes illustrates this point in this way:
But why didn’t God create humans as perfect beings so that humans would not err?
According to Descartes, God could have willed it. God could have created humans as perfect beings, but according to Descartes, man cannot fathom the mystery of God. Hence, God’s motives and reasons for creating humans as imperfect beings are incomprehensible.
What about the origin of truth? How certain is Descartes about the existence of the “I”? What if God deceives him?
Here, Descartes brought again the demon problem. According to Descartes, since God is perfectly good, then he cannot deceive us. This is because if God deceives us, then he is not God because “to deceive” someone is an act of an imperfect being. Therefore, Descartes is certain about the existence of “truth”, of the “I” because God as a perfect being would not deceive us. What this implies is that God cannot be the source of error.
Now, if God is not the source of error, then who is responsible for the existence of error or falsity? For Descartes, the concepts of “intellect” and “will” are they keys to answering this question.
According to Descartes, both the intellect and will are gifts from God. Descartes argues that the intellect as the faculty of knowledge cannot be the source of error. Because the intellect simply perceives ideas, it cannot err. It must be noted that for Descartes, the intellect allows us to perceive ideas only; it does not make judgments. This is because judgments are the business of the will. Now, since it is judgments that can either be true or false, and that since judgment is the primary function of the will, then, according to Descartes, it is the will that is the source of error. It is the will that commits mistakes.
How is this possible?
According to Descartes, when the will (which is the faculty of choice or freedom of the will) passes judgments on matters that are not clearly understood, error comes into the fore. What this implies at the end of it all is that, to avoid error in judgment, as Descartes would have us believe, it (judgments or decisions) must be guided by reason or the intellect.
Meditations on First Philosophy (Meditation V): On the Essence of Material Objects and more on God’s Existence
It must be noted that God is reconsidered in meditation V. Meditation V is also a transition to a more important sixth meditation.
One of the central points in meditation V is Descartes’ attempt to know whether materials things exist independently of the mind. But because Descartes has put the testimony of the senses in doubt, then Descartes just “see” these materials things. In other words, Descartes simply observes these things. Thus, Descartes resorts to the intellect and consider more carefully the “idea” of these things, which is all that is available to him.
However, it should be noted that Descartes postponed the discussion on whether materials things exist in reality outside of the mind until the sixth meditation and instead discussed what he thought as the 3rd proof of God’s existence. Meditation V, therefore, is devoted to the discussion of the discovery of the 3rd proof of God’s existence.
Now, Descartes argues that clear and distinct ideas have a nature or essence of themselves. And for Descartes, this necessarily implies existence. Since our idea of God is clear and distinct, Descartes, concludes that indeed God exists. Descartes illustrates this argument this way:
God, by definition, is a being of infinite perfection.
Existence is a perfection (for everything that exists is perfect; otherwise, it cannot exist).
Therefore, God exists.
Meditations on First Philosophy (Meditation VI): On the Existence of Material Objects and the Real Distinction of Mind and Body
We know that since the intellect conceives some things clearly and distinctly, some things necessarily exists therefore. Now, the question is, what is our proof that these things really exist in reality? Or how do we know that indeed material things exist?
Put differently, we know that the essence of material things is extension. In other words, all things are extended. Hence, to be a thing is 1) to have size and shape, 2) to endure, and 3) to be movable and changeable. Now, are they any?
To answer these questions, Descartes initially offers the discussion on the dynamics of the imagination as proof. But Descartes thought that although the imagination can produce images of reality, it cannot be a strong proof to the existence of materials things. This is why Descartes turns to the senses.
Indeed, Descartes perceives that he has a body that exists in the world, and this body can experience pain, pleasure, hardness, and the like. And this body can perceive other bodies with extension, shape, movement, hardness, heat, color, smell, tastes, and the like.
Now, Descartes was convinced that these perceptions all come from outside sources, and that these perceptions come to us involuntarily. It is clear that since material things exist, it is logical to suppose that the source of sensory ideas in some way resembles the ideas themselves. Hence, for Descartes, all knowledge comes from without via the sense.
But isn’t it that for Descartes the senses are unreliable sources of ideas and knowledge? In fact, Descartes insists in the earlier discussion of the Meditations (as well as in the Discourse) that we should not rely on the senses because they only deceive us?
Descartes seemed to have changed mind here. According to Descartes, the situation is now very different from the first meditation. For Descartes now knows that God who created these material things “exist” and is “not a deceiver”. Therefore, those material things that are perceived by the mind via the senses exist in reality. Descartes illustrates his argument this way:
I have a “strong inclination” to believe in the reality of the material (extended) things that I seem to sense. (To put it differently, their independent reality seems to be one of the things I am “taught by nature”.)
God must have created me with this inclination.
If material things do not exist independently, then God must be a deceiver.
But God is not a deceiver.
So, material things exist with those properties I conceive to be essential to them.
Final Note: On the Discussion Between Mind and Body
For Descartes, mind and body are both substances, and so they are completely distinct from each other. On the one hand, mind is a non-extended thinking thing. On the other hand, body is an extended non-thinking thing.
Part of the reason why Descartes aims to establish the distinction between mind and body is to establish the fact that the soul is immortal. As we can see, the distinction between mind and body opens up the possibility of establishing the immortality of the soul since it involves the idea that the “decay of the body does not imply the destruction of the soul”.
But how does Descartes prove the crucial claim that the mind and body are capable of existing apart from each other?
Here, Descartes invokes what he calls 1) clear and distinct conception of the mind as a thing that is complete and does not require any extended qualities in order to exist, and 2) the corresponding clear and distinct conception of the body not requiring any mental properties in order to exist.
As we can see, Descartes’ real distinction argument turns on the reliability of so-called clear and distinct perception. However, Descartes did not give a concrete example of a mind existing apart from the body, and a body existing apart from the mind.
Now, despite the real distinction between mind and body, Descartes argues that these substances nevertheless interact with each other. According to Descartes, the mind causes certain changes in the body and the body in the mind. But when asked about the specificity of this interaction, Descartes was unable to answer and instead appeal to God. In Descartes’ understanding, God sets up or institutes those particular causal relations between mind and body that are, in general, the most conducive to the well-being of the composite of mind and body. Descartes illustrates:
God can create anything that I can clearly and distinctly conceiveꟷthere being no impossibility in it.
If God can create one thing independently of another, the first thing is distinct from the second.
I have a clear and distinct idea of my essence as a thinking thing.
So, God can create a thinking thing (a soul) independently of the body.
I also have a clear and distinct idea of my body as an extended thingꟷits essence.
So, God can create a body independently of a soul.
So, my soul is a reality distinct from the body.
So, I, as a thinking thing (soul), can exist without my body.
Concluding Remarks
At the end of the Meditationson First Philosophy, Descartes was convinced that he has achieved his main objective: skepticism and solipsism have been defeated and the basic structure of reality has been clearly delineated, namely, God, souls, and material things. Descartes also concluded that reality is composed of infinite substance and two kinds of substances: thinking and extended substances. Finally, Descartes believes that he has successfully shown that indeed knowledge is possible, that, contrary to the position of the Skeptics, the human mind can attain knowledge.
