Modern European Philosophy: Idealism - Berkeley & Kant

George Berkeley (1685 - 1753 CE) was an Irish Anglican Bishop and philosopher.  He was both an Empiricist, one of the main three along with Locke and Hume, as well as an Idealist, along with Kant, who we will consider next, and Hegel, who we will examine next time.  Idealism asserts that reality is essentially mental or mentally constructed.  I mentioned last time that for more skeptically inclined thinkers, there is no difference between epistemology and ontology, no difference between how we can understand things and how things exist.  For idealists, this skepticism means there is no understanding or existence apart from the mind.

Berkeley was born in the Berkeley family castle in the Kilkenny county of Ireland.  He attended and then became a lecturer at Trinity College of Dublin.  In 1710 he published his central text, An Essay Concerning the Principles of Human Knowledge.  His primary target for criticism was Locke, and his distinction between objective primary qualities and subjective secondary qualities.  In 1728, Berkeley married and travelled to America.  He bought a plantation, unfortunately named ‘Whitehall’, in Rhode Island, but after he failed to secure funding from Britain to get it (and slaves) up and running, he returned to London.  While in America, he planned on setting up an ideal (ha!) city and college in Bermuda, a plan that never materialized (ha, again).

Berkeley’s works were unpopular in his lifetime, and they remained so until the mid 1800s when new scholars shed light on his work as a precursor of fellow idealists Kant and Hegel, whose work was then dominating the intellectual scene.  In 1866, when the first university of California was founded just north of Oakland, a group of students stood watching ships head out to sea through the Golden Gate, seventy years before there would be a bridge.  One of the students, Frederick Billings, who would go on to be the president of the Northern Pacific Railway and a trustee of the university, was reminded of a quote from the final stanza of George Berkeley’s Verses on the Prospect of Planting Arts and Learning in America, “Westward the course of empire takes its way”.  Billings suggested that the university and community springing up around it be named after the philosopher, mispronounced by Americans still today.  This suggests that the name was inspired by Berkeley’s pride in European colonialism, and not his radical Idealism.  Interestingly, at the time there was a strong temperance movement at the university, the community was declared an alcohol free zone, and the sale of alcohol was prohibited within a mile of the campus.

While Kant and Hegel, both Idealists like Berkeley, argued that our reality is mentally constructed, and so the shape of our world and reality is necessarily the shape of our mental constructions, neither denied the existence of the material world.  Similar views were held in the ancient world, in Indian Buddhism, Greek Neoplatonism, and Chinese Daoism.  Berkeley took Idealism to a greater extreme as an immaterialist, denying the material existence of the world apart from perception and declaring reality to be a dream.  In this way, he is much like the Rationalist Leibniz, who denied the genuine existence of anything other than the infinite set of monads.  He is also much like Descartes, if Descartes had been content to live in a skeptical dream ruled not by a demon but by a rational and loving god.

As an immaterialist, Berkeley argues that material things only exist in the minds of perceivers.  Existence requires perception.  I often illustrate the juncture of the world and the mind, realism and idealism, objective and subjective, by gesturing to a table and the area around the table, noting that we all understand the table to be solid and the space around it to be empty even though neither the table nor anything else in existence is simply or perfectly ‘solid’, nor is the space around it simply or perfectly ‘empty’.  While our common shared understanding, a simplification of the situation, is useful, it is as much a mental polarization and categorization as it is a physical situation.  If by ‘existing’, we mean something enduring, staying the same over a period of time, and if we accept that there are no things that remain perfectly static over any duration of time, then nothing that we perceive truly exists.  As mentioned last time with Empiricism, we get our idea of ‘true’ from our experience of solid things in the world.  In the same way that ‘solid’ is a category of the mind that can never apply perfectly to the world but can indeed be useful to apply to the world, it is useful but not perfect to speak of things as ‘true’.

While Hegel believes that our subjective mental understandings are always one and the same as the objective material world, his Idealism does not go as far as Berkeley’s immaterialism.  Berkeley uses the example of an apple, and others often speak of his ideas using the example of a chair.  For Hegel, the being of an apple and its being an apple requires our application of understandings, but if we walk out of the room and leave the apple behind, it ceases to be understood as an apple and ceases to be understood as enduring but it remains in the room, undefined.  For Berkeley, if God does not choose to maintain the existence of an apple outside of our perception and understanding, the apple ceases to exist.

There is a story often told of a famous reaction to Berkeley’s immaterialist Idealism.  Samuel Johnson, the famous English author and critic, was discussing Berkeley’s immaterialism with James Boswell while walking home after church on a Sunday morning.  Johnson became quite upset at Berkeley’s denial of the independence of the material, and so he walked over to a large rock, gave it a kick, and pronounced, “I refute it thus!”.  Of course, both Berkeley and Hegel would object that Johnson hardly proved the independence of the objective from the subjective with his foot, and yet there is something to be said for the denial of absolute immaterial Idealism by way of the action demonstrating physical Realism.  We do not treat life as if it were merely a subjective dream, any more than we treat others as if they are figments of imagination in the mind of the solipsist.

Consider a Chinese Zen story in which two monks are debating about the nature of reality, like Samuel Johnson arguing about a large rock before them.  Their master walks over to ask what they are arguing about, and the first monk says that his opponent is arguing that the rock is really in the world, while he is arguing that the rock is really in the mind.  The master tells the first monk that, if the rock was really in his mind, he would have a hard time lifting his head off the floor every morning.  While Zen Buddhism often emphasizes the subjective nature of reality, this story serves as a realist counter-weight, reminding us that “The rock is subjective” is both a Realist assertion as well as an Idealist perspective.

There are similar parallels found in the interactions between the ancient Greek philosophers Diogenes and Plato.  Diogenes, who believed that Plato had hijacked the lineage of Socrates, believed in living a simple, practical and cynical life, and he was fond of heckling Plato as he lectured about Idealism.  Plato, an ancient Idealist, believed that the forms of things are eternal and real compared to the physical manifestations of things, which are mortal and unreal.  Unlike modern Idealists such as Kant and Hegel, Plato’s ideas are above in the heavens, and it is only through study and contemplation that they find their way into our heads.

According to one story, Plato was teaching about ideal forms and pointed to several cups on a table, arguing that there were many physical cups, but only one idea and form of the cup, which was in the mind, superior to the physical copies.  Diogenes, heckling Plato from the gathered crowd, said that he can see the cups, but not this superior ideal form.  Plato replied that we can have it in our mind.  Diogenes picked up a cup, noted that it was empty, and asked Plato where the emptiness of the cup comes from.  Plato paused, unsure of the answer.  Plato did not believe void to exist, as it had no form.  Diogenes walked up to him, tapped him on the forehead, and said, “I believe that you can find the emptiness here, Plato”.  In another story, Diogenes was asked by some who had gathered if he could lead them to Plato such that they could hear his famous philosophy.  Diogenes led them to a deserted area of town, gestured into the empty air and said, “May I humbly present you the great philosopher Plato”.  This is, of course, another jab at Plato’s idealism and putting theory and the ideal over the practical and the real.

Berkeley did not deny the existence of chairs or apples, but he argued that they are not material objects we share in an objective reality, but rather conceptions we share in a subjective reality.  Berkeley argued that belief in substance beyond perception is unverifiable.  Anything we could experience as existing would have to be perceived, and thus experienced.  If by ‘substance’ or ‘material’, we mean something that is senseless, unlike ourselves, it is impossible for us to experience things as senseless.  Berkeley argues that the senseless material would have to be a perception of something not perceiving, awareness of non-awareness, an idea of something that is devoid of ideas.  He considers this to be an insurmountable contradiction.

Very similar to Hegel’s criticism of Kant’s ‘thing-in-itself’, which we will study soon, Berkeley argues that Locke’s primary objective qualities must be merely subjective to us, and cannot be known otherwise.  Berkeley asks us to attempt to imagine something outside of all perception, and concludes that the merely objective, the simply material, is inconceivable to us.  Though Locke and others argue for it, through ignorance they do not realize that they cannot conceive of what they are asserting.  Here, of course, “can’t conceive of” means cannot reasonably and thoroughly conceptualize.  While Locke can imagine that material things such as apples are objective in particular ways beyond our conceptions, Berkeley argues that, if Locke is honest with himself, he will realize that whenever he imagines the objective qualities of an apple, he is experiencing a conscious subjective perception of an apple as an idea, and cannot conceive of the apple or its qualities beyond perceptions.

Reality consists of minds, which Berkeley refers to as spirits, and sensations, ideas and perceptions of these minds.  While we can have no direct experience of other minds, we believe in other minds because they have ideas, sharing many of them with ourselves.  In the same way, if we see a table jumping and singing in a cartoon, we suspend disbelief and understand it is, for the purposes of fiction, a living, conscious thing that for some reason had the idea to burst into song.  Thus, Berkeley is no solipsist, as he argues that our recognition of the ideas of others is empirical evidence that they, like ourselves, exist.  We subjectively exist to ourselves both in consciousness (our mind) and our self conception (our idea and image of self).  Others subjectively exist to us as ideas in our recognition of the evidence that they have ideas, which leads us to conclude, unlike the Solipsist, that they are minds and conscious like ourselves.  Just as it is difficult to maintain skepticism when one is kicked in the shins, it is difficult to perceive beings that express themselves the ways that we do and doubt that they are conscious.

Likewise, similar to previous philosophers we have studied, Berkeley argues that the order and beauty of nature is evidence that reality is itself intelligent, having ideas of its design, and thus leads empirically to belief in God.  Because we experience all things as ideas, but are not able to will the world to exist or not, Berkeley reasoned that there must be a superior mind that causes the existence of ideas via its own ideas.  Berkeley argues that “physical” reality is so hard for us to doubt (though not impossible, as Descartes had shown) because it is the idea of God, more powerful than our own ideas.  Recall that Berkeley’s fellow Empiricist Hume argued that impressions are stronger than ideas.  In the same way that we intentionally conceive of ideas, Berkeley argues that God intentionally (as primary cause of all) conceives of our reality, and so our direct impressions are the ideas of God, from which we derive  the weaker sensations that are our inferior ideas.

Berkeley argued against Locke’s distinction between objective primary qualities and subjective secondary qualities, using similar examples that the Pyrrhonian skeptics used against dogmatism and Hume borrowed to use against Rationalism.  Berkeley argues that the qualities Locke took to be objective and physical are also themselves subjective and mental.  Sextus, the Pyrrhonian mentioned previously, pointed out that when one has not yet entered a bath house, one does not feel cold, but after a warm bath one feels cold exiting the bath house.  Locke used a similar example of placing one’s hand in a warm or cold bucket of water, arguing that this demonstrated that heat is a secondary, subjective quality.  Like the Pyrrhonian skeptics, Berkeley used similar examples to attack Locke’s primary qualities, such as motion and length, and show them to be subjective and dependent upon the position and disposition of the viewer.  Berkeley also argued against Locke’s friend Newton, arguing like Einstein that time and motion are not objective and absolute but subjective and relative.

As a final thought, the late American comedian Bill Hicks is often quoted about never hearing a positive story about drugs in the news, saying, “Today a young man on acid realized that all matter is merely energy condensed to a slow vibration, that we are all one consciousness experiencing itself subjectively, there is no such thing as death, life is only a dream, and we are the imagination of ourselves...Now, here’s Tom with the Weather”, a bit that is a bit Berkeleyan.


Immanuel Kant (1724 - 1804 CE) was a German philosopher.  Technically, Kant was born in what was known as Prussia, in the town of Konigsberg, what is now known as Russia, the town renamed Kaliningrad.  While Kant grew up in a devotedly Pietist family, a branch of Lutheranism that placed a great emphasis on individual morality and purity, he found himself drawn to Rationalism and in opposition to religious ceremony.  While a professor at the University of Konigsberg, Kant was always “indisposed” whenever it was his turn to participate in church services.  As one could guess by Kant’s employer, he never traveled far from his hometown.  He was known for being obsessively punctual, and legend has it that he would take his daily walks after lunch so routinely that housewives would set their clocks as Kant passed by their houses.  Kant would always walk alone, as he believed it proper and healthy to breathe through one’s nose in the open air.  He was also deeply disturbed by perspiration.  It is said that the only morning Kant broke from his usual strict routine was to purchase a newspaper announcing the outbreak of the French Revolution, an event that, like the work of Kant, had a great impact on Hegel, the next figure we will study.

Just as Locke is famous for his work in both epistemology and political theory, Kant is famous for his work in both epistemology and ethics.  While we will focus on Kant’s epistemology for the purposes of this class, just as we focused on Locke’s, we cover Kant’s theory of morality in the Ethics class, which we can briefly cover here just as we briefly covered Locke’s political influence.  Kant believed in strict, rule abiding morality, which he considered the true means of Christian salvation, not religious ritual.  Using our universal faculty of reason, which I will explain in detail as we cover his epistemology, Kant argued that we can come to understand absolute principles, morals to which we should always adhere.

Kant argues that if we are rational, we are concerned with absolutes that are universal.  The example Kant gives is, “Do not lie”.  If we always lied, society would fall apart, and so we must always tell the truth if we choose to speak and never lie.  A firm believer in duty, Kant argues that we must be moral no matter the consequences.  Even if we know that a lie might have a good chance at saving our own life, immorality is never justified.  Needless to say, many find this stance a bit hard to put in practice.  John Stuart Mill, who we will study with Utilitarianism, argued for the opposite position, that the ends justify the means, and morality is only for the purpose of achieving happiness.

Turning to epistemology, Kant was primarily concerned with metaphysics, the laws of being that structure the laws of nature.  Just as Plato’s Idealism was concerned with the heavens while modern Idealism was concerned with the mind, so too Aristotle’s metaphysics was concerned with the workings of the heavenly bodies, while Kant’s metaphysics was concerned with the limitations of the human mind.  This is very similar to Locke, who was primarily interested in the limits of human knowledge and understanding.  Like Kant’s fellow Rationalist Leibniz, whom he admired and studied, Kant believed in the principle of sufficient reason, the principle of noncontradiction and the rational, objective and universal application of logic, a subject which Kant believed had been completed and closed by Aristotle.

Like Descartes and Hume, Kant was well aware of ancient Greek Pyrrhonism, as well as the challenge that skepticism, including the work of Hume, posed to metaphysics and Rationalism.  Aristotle hated ancient Greek skeptics, arguing that they were “mere destroyers”, and no better than plants when it came to debate.  As mentioned, Kant famously wrote that Hume woke him from his “dogmatic slumbers”, and Kant’s work, like that of Descartes, is concerned with finding what can be defined as certain and objective in the face of doubting all assumptions acquired through experience.  Kant sought specifically to rescue Leibniz’s principles of sufficient reason and noncontradiction from being considered mere assumptions.  He argued that metaphysics could go beyond both dogmatism and skepticism to become ‘critical’, like Descartes questioning all truth to distinguish what is objectively true beyond all appearances.

In his early work, Kant wrote about philosophy and the natural sciences, reconciling the work of Newton with philosophy and theology.  Like Descartes, Kant argued that the regularity of the cosmos shows that it is intelligently designed and operates in a rational manner.  
Strangely, in his old age Kant hypothesized that electricity caused strange cloud formations and epidemics of disease in cats.  Awoken by the skepticism of Hume, Kant spent a ten year “decade of silence”, from 1770 to 1780, working on the first of his three Critiques, the Critique of Pure Reason.  Originally, Kant thought the work would take three months.  This first Critique focused on objective rationality exclusively separate from the influence of experience.  Kant’s second two critiques, the Critique of Practical Reason and the Critique of Pure Judgement, focused on the use of reason in practical matters.  The Critique of Practical Reason dealt with freedom and morality, and the Critique of Pure Judgement dealt with beauty and art.  We focus on the first Critique, as we have been focusing on epistemology and ontology.

Much as Plato sought to incorporate while overcoming Heraclitus’ skepticism in ancient Greece, Kant sought to incorporate while overcoming Hume’s Empiricism with Rationalism.  Kant argued that Hume was right about the world of experience, which can only be known subjectively and imperfectly, but not about the logical operation of reason, which we can know objectively and certainly.  Recall that Locke compared the faculty of understanding to the human eye.  Kant’s conception of reason is often illustrated with the metaphor of eyeglasses.  While we may not be able to know what the world looks like without our glasses, but we can examine the glasses to see the frame through which we view the world.  Likewise, Kant argued that we can critically examine our faculty of reason to understand how our ideas must take shape.  This would put metaphysics, such as the principle of noncontradiction, “on the secure path of science”.  ‘Science’ in German is Wissenschaft, or “knowledge-stock”.

Unlike Berkeley, Kant believes that there is a “thing in itself”, the “Ding an sich” in the German, beyond appearances, using the Latin term ‘noumena’ for the things themselves and ‘phenomena’ for our perceptions of them.  Kant argues that we can never know the thing in itself, but we can know the regular way that we can form ideas about appearances.  Next week, we will study Phenomenology, the attempt by Hegel, Merleau-Ponty and others to create a “science of appearances”.  Kant used another pair of Latin terms to distinguish between rational and empirical truth, to separate the objective from the subjective.  That which is known before and apart from all experience Kant labeled ‘a priori’, and that which is known after and through experience Kant labeled ‘a posteriori’.

The central question of the Critique of Pure Reason is, “How are synthetic a priori judgements possible?”.  To understand this, we need to understand Kant’s additional distinction between analytic and synthetic judgements.  When we analyze a thing, we break it into its component parts.  When we synthesize a thing, we put many parts together to form a greater whole.  Kant was concerned that skepticism threatened reason’s ability to deduce additional knowledge from previous knowledge, to synthesize greater and additional truth.  However, as a Rationalist, Kant sought knowledge deduced apart from all inductive experience.  Thus, Kant’s concern for the “synthetic a priori”, that which can be deduced as objective and certain before and apart from all experience.  As mentioned with Rationalism and Leibniz, if we know that 2 + 3 = 5, and that 5 + 6 = 11, we can deduce, without need of any particular experience, that 2 + 3 + 5 = 11.

Essentially, Kant sought to rescue Aristotelian logic, including the principle of noncontradiction, from Hume’s charge that all truth is assumption, and he hoped to do this by starting from self-certainty, as had Descartes, and synthesizing the principles of logic by deduction from there without relying on assumptions based on experience.  This would reveal that logic was truly transcendental, necessary and universal to all experience, the frame through which we must grasp any idea or understanding.  While the word ‘transcendent’ means exclusively removed from and separate, like a sage who has transcended the world of desires, ‘transcendental’ means consistently throughout and universal.  Much like being wet is a necessary condition of being in the ocean, the transcendental is a necessary condition of all that can be coherently experienced and conceived.  The American Transcendentalists, such as Emerson and Thoreau, argued that reality is an undivided whole beneath divisions imposed by the mind, a view they found in ancient Indian and Greek thought, and thus the oneness of things is not above and beyond, not transcendent, but within and throughout, transcendental.

Unlike the Transcendentalists, Kant was very exclusive in his thinking, believing that the objective and subjective should be exclusively divided to prevent misunderstanding and maintain coherence, much as Locke had attempted to divide objective primary qualities from subjective secondary qualities.  Central to this for Kant was the exclusive definition and operation of the faculties of understanding and reason, Verständnis and Vernunft in the German.  Thus, Kant’s first Critique is the Critique of Pure Vernunft, of reason exclusively examined apart from sensation and understanding.

As we will cover next week, Hegel took up Kant’s distinction between the faculties of understanding and reason, but influenced by fellow German philosopher and Idealist Schelling, Hegel argued that understanding and reason must be synthesized and united, not exclusively divided.  Kant would have considered this the ultimate confusion, arguing in his first Critique that the mixing of understanding and reason is a major source of philosophical error as each has properly exclusive jobs to do.  For Hegel, Kant’s exclusive division between understanding and reason, as well as the division between the thing-in-itself and our experience of it, were failures of Kant’s inability to synthesize the whole with reason above and beyond the divisions of understanding.  While Kant thought that reason should ultimately serve understanding, maintaining exclusive distinctions, Hegel thought that reason should transcend while extending understanding, uniting all in the transcendental One, much like that of the Transcendentalists.

For Kant, experience requires two separate elements, sensation and understanding.  Much like the division of matter and form for Plato and Aristotle, sensation is the raw content and understanding is the form and categorization that makes sensation coherent.  Consider Berkeley’s example of an apple.  As we look at an apple, our experience is a union of the undefined sensation and the exclusive categories with which we understand the sensation (such as red, solid, apple, and fruit).  Without both, there is no coherent experience of the apple.

Kant argues that we can become confused, and believe that the category of ‘apple’ and ‘red’ exist in the world itself, are present in the thing-in-itself, but if we are being rational and exclusive we determine that the categories of understanding are not given in the world but conceptions of the mind.  Thus, the thing-in-itself cannot be known, but the categories of understanding, when exclusive, noncontradictory and coherent, can be known with pure clarity.  Unlike Locke’s primary qualities, for Kant the objective is mental, not physical, like the forms of mathematics and logic.

Understanding takes various sensations and synthesizes them into categories, while also exclusively dividing the categories from each other.  After we experience several objects, some of which are red, and some of which are apples, we form conceptions of redness and apples.  Note that consciousness, self-certainty (as we had with Descartes), is itself also in the picture as the continuity of experience (as we had with Locke).  As the self experiences the world through its understanding, it finds itself with pre-existing fundamental categories, which Kant calls foundations (Grundsätze in the German, which also translates as ‘principles’).

Hegel was critical of Kant for pulling these categories from seemingly out of nowhere without describing their development, but Kant believed that the origin of the foundational categories was beyond human comprehension.  One of these foundations was the category of causation, which Hume considered to be an assumption learned through experience.  Kant, targeting Hume in particular, argued that causation is a foundational category that is present in the mind before and apart from all experience, and that we find ourselves categorizing the world in terms of causation in a way that cannot be derived from experience.  Another foundational category of Kant’s is substance.

Reason, separate from understanding, serves as a higher level of understanding, as an understanding of understanding.  Just as understanding joins and separates sensations, reason joins and separates understandings.  Judgement performs both of these activities, dividing sensations into groups for understanding and dividing understandings into groups for reason.  Reason infers similarities and differences of understandings, forming ideas.  Ideas, such as freedom and beauty, central examples used by Kant and fleshed out in the second and third Critiques, are not directly experienced in the world but are formed as ideas by reason through inferences drawn from the understanding.  For example, we can see several things moving, and then based on the understanding of the varieties of motion come to ideas about freedom and necessity.

For Kant, it is crucial to keep reason separate from understanding.  Reason is transcendent, whereas understanding is transcendental.  Understanding is thoroughly involved with sensations, but reason is separate from the sensible world, free to form ideas.  This corresponds to Descartes’ dualism, in which the body is determined and the mind is free, except for Kant both understanding and reason are mental.  While the understanding is passive, categorizing sensation as it happens, reason is active, producing ideas as it sees fit.  Experience is determined by the understanding, but ideas are formed from the free use of reason within the imagination, separate from, though derived from, experience and understanding.  Reason is free to wander, taking a wider view, however it may not contradict the understanding.

For Hegel, reason’s job in history is to contradict understanding, to contradict accepted dogmas and force progressively greater synthesis beyond exclusive boundaries.  For Kant, contradiction with the understanding results in incoherence, an improper mixing of understanding and reason, not a greater synthesis of knowledge.  For Hegel, understanding is extended by contradiction, transforming the incoherent into the coherent.  For Kant, reason is extended by noncontradiction, avoiding the incoherent and maintaining the coherent.  Both believe that reason works through dialectic, by weighing both sides of a potential judgement and then extending the understanding, arriving at a greater understanding than before.

For Kant, understanding has jurisdiction over things, whereas reason has jurisdiction over ideas.  In this sense, while the understanding categorizes things, such that we experience things as substances that cause and are affected, our ideas of substance and causation are part of our free, abstract reasoning, which judges the categories of the understanding to produce abstract ideas.  This would mean that ‘substance’, ‘nature’ and ‘beauty’ are ideas, not things.  They are produced by reason, not experienced in the world.

While Kant does believe that reason is free, as does Hegel, Kant is notorious in epistemology and ethics for arguing that we are free, but when we are rational we are merely free to conform to the truth.  Kant believes that reason, when purified, is rational, and can determine ideas that are necessary and true.  As these necessary ideas are objective, not subjective, reason is free, but free to find the singular, necessary and objective truth or to be mistaken and confused.  Bill Hicks, the comedian quoted earlier, had a bit mocking American television, announcing, “You are free...to do as we tell you!”.  This is disturbingly similar to the Nazis posting, “Work is Freedom” above the entrances to concentration camps, an inspiration to George Orwell as he wrote doublespeak slogans for the tyrannical ‘big brother’ government of his novel 1984, such as “War is Peace”.

In metaphysics and ethics, Kant believed that true freedom was achieved when one believes the objectively truth and does one’s duty, free from the many passions attached to the senses.  Completely in line with ancient cosmological conceptions, Kant saw the passions as many, reason as singular, and conformity to the singular as freedom from the many.  Kant used the metaphor of an island in a stormy sea to illustrate the rational mind amidst the flux of the sensual world, objective and rational in the sea of the uncertain.  Schopenhauer, a Kantian, used a similar metaphor of a ship on a stormy sea, more skeptical than Kant as a boat is not fastened down but drifts with the current of the passions.  Kant, who was rather stoic, says we should seek the satisfaction of needing nothing, of not seeking satisfaction from anything in particular.

While the understanding is passive, and can only judge sensations as they happen, reason is free to speculate as to what could, or should happen.  Hume famously argued that one cannot derive an ‘ought’ from an ‘is’, that we cannot know what should happen merely based on what is happening.  Kant meets Hume halfway.  While understanding, which judges what is, is properly separate from reason, which judges what should be beyond what presently is, reason can come to necessary rational conclusions about what should be.  ‘Ought’ and ‘is’ are two separate things, as Hume argued, but for Kant reason can derive what objectively ought to be.  Kant’s central example of morality, “Do not lie”, is a necessary conclusion that reason arrives at when it properly surveys the understanding and speculates with ideas.  The conclusion is seen by reason to be universal, necessary, and objective.  Purposeful unity, for Kant, is the highest formal unity, resembling the unity of the rational cosmos itself, both driven to purpose by necessity.

Not only does reason figure out what should be that is not, but reason also has ideas about other minds and their purposes, including the teleological design of the rational universe.  When we ask about the existence of a thing, we are often concerned with the purposes of others involved.  While Kant argued that reason cannot prove the existence of God, disagreeing with previous Rationalists, he argued that reason is the instrument through which we could have ideas about God and the purposes of things, about what things should be used for and what other people should do.  Notice that reason is concerned with ideas, and is therefore the proper tool of both religion and science, a common theme of our philosophers so far.  As mentioned, Kant did not enjoy religious ritual, and was quite deist in pursuing the divine through exclusive rationality.

Nietzsche said Kant was like a fox who admirably broke out of his cage, only to lose his way and wander back into the cage.  While Kant had hoped to justify and preserve metaphysics, his skepticism towards our knowing the thing-in-itself, ultimately lead to the downfall of metaphysics, heralded by Nietzsche.  Heidegger admired Kant’s notion that the appearance of a thing is not the thing-in-itself, and argued that what Kant and later philosophers learned from this is that, “Every revealing is a concealing”.  Appearances conceal as much as they reveal.  For Heidegger, this means that our being is essentially bound up with time.  Realists, like the Scottish Realists who had an impact on Analytic philosophy, as well as Ayn Rand, thought that Kant had gone too far agreeing with the skepticism of Hume.  Similar to Johnson kicking the rock, Realists argue that it is ridiculous to speak of substance as an assumption or a category of the mind, as substances are clear and objectively present in the world.