Descartes: wax argument & knowledge

Descartes uses his wax argument, as described in my previous post, to construct a system of knowledge. He considers his perceptions to be unreliable, as he discovered in his wax argument, and he discards them completely when determining what he should base his knowledge on. He decides that only deduction can be used as a method for obtaining knowledge. At this point, Descartes brings God into his argument and decides that he must trust his senses at least a little bit. After all, God provided him with a working mind and sensory system. And, since God is benevolent, he does not desire to deceive Descartes in any way. Further, he believes that there is an external world because perceptions come to him involuntarily, and the things that he perceives must be external to his senses. From this, he finally entertains the idea that it may be possible that he may acquire knowledge about the world through both deduction and perception. Descartes further argues that knowledge is represented in the form of ideas and that rational knowledge is incapable of being destroyed.

Descartes: wax argument

Descartes uses what is known as his wax argument to demonstrate the limitations of the senses. He considers a piece of wax, and notes that his sense inform him of certain characteristics about that piece of wax. These characteristics include things like its size, shape, color, odor, texture, and so on. When he brings this piece of wax to a flame, however, these characteristics are completely altered. Despite these different characteristics, Descartes notes that it is still the same piece of wax as beforehand. Whether it is solid or liquid, hard or soft, hot or cold, it is still the same exact item. So, Descartes determines that he cannot rely upon his senses to determine the true nature of the wax, but rather upon his mind. He writes, "Thus what I thought I had seen with my eyes, I actually grasped solely with the faculty of judgment, which is in my mind." I like Descartes' wax argument because it shows exactly what he wanted to prove--the limitations of the senses. Your senses can obviously provide you with a ton of information, but they are incapable of reasoning through that information. That is what makes the mind so important--it must make sense of everything that the senses bring in.

Kant: metaphysics

Kant says that metaphysics relies on the faculty of reason, and therefore is independent of experience. Reason, he says, aspires to know about things in themselves and may sometimes mistakenly apply concepts of understanding to matters outside of experience. Kant says that there are three ideas of reasoning: psychological, cosmological, and theological. Psychological deals with our ideas and concepts of substance and the soul. Cosmological gives rise to four sets of antinomies, and theological obviously deals with our ideas of God. Kant argues that reason oversteps its bounds in each of these cases and often makes claims that can be confusing with appearances. Metaphysics, unlike mathematics and natural science, can go farther than it is reasonably capable of going, and in that way it can explore the full extent and capabilities of human knowledge. I'm a bit confused by the way that Kant talks about metaphysics, but from what I do get, it seems like he accepts metaphysics as something complicated and something he doesn't fully understand. I like that he doesnt try to make too many assumptions about it, and the arguments that he does present seem to make sense to me... but like I said, I don't entirely get it.

Kant: natural science

Kant thinks the same thing about natural sciences that he thought about mathematics. He believed that synthetic a priori judgments form the foundation of natural science. Pure natural science is possible, according to Kant, because of the pure concepts of our faculty of understanding. These concepts give a law-like structure to our experiences (one, for example, is that every effect has a cause). Kant is sure to distinguish between judgments of perception and judgments of experience. A judgment of perception is based on a subjective sensation, while a judgment of experience attempts to draw objective, necessary truths from experience. Since science is an objective body of knowledge, it must rely upon objective laws (pure concepts of our faculty of understanding). These laws are just as much apart of our understanding as are the concepts of space and time. So pure natural science is possible for the same reasons that pure mathematics is possible--they rely on parts of our natural concepts.

Kant: mathematics

According to Kant, the truths of arithmetic and geometry are synthetic judgments because they contribute significantly to our knowledge of the world. But these judgments are also a priori because they universally apply to all objects of our experience, without having been taken from the experience itself. The question then becomes, how do we come to have such knowledge? One might think that we indeed come to know these things through experience, rather than a priori. After all, you need to be familiar with numbers to even understand what 2 + 5 = 7 means. Kant argues that we know these things a priori because of "pure forms of sensible intuition," and not experience. He believes that things in arithmetic are directly associated with things in time, and things in geometry are directly associated with things in space. Space and time are absolute and derived from our minds. So, our concepts of space and time allow for us to understand mathematical concepts without being exposed to those concepts.

Kant- The first and second antinomies

The first two antinomies, the first having to do with space and time, and the second having to do with the simple and composite, both have opposing propositions (the thesis and antithesis). Whereas in the 3rd and 4th antinomies Kant argues that both the thesis and the antithesis are both actually true (and only mistaken to be contradictory when one takes phenomena to be noumena), Kant argues that the thesis and antithesis of the 1st and 2nd are both false. One might wonder how to contradicting propositions can both be untrue. It seems to be like the law of non contradiction in logic: P v ~P (P or not P), i.e., either something is the case or it is not. Kant explains that it is possible for two ocntradicting statements to both be false when "the concept lying at the ground of both of them is self-contradictory". Kant gives the example of a square circle. Two contradictory statements about square circles can both be false because the concept of a square circle is inherently contradictory. Because of that, any proposition which asserts anything about square circles is false. In the same way, when it comes to the question of whether or not space and time are infinite, or whether the constituents of the world are simply or composite, making any assertion of either the thesis or antithesis of either antinomy is assuming that experience is fit to give an answer. Becausethe world given to us IS equivalent to our experience, to suppose that our experience has the property of being simple or composite or infinite or finite is a mistaken notion.

Kant- The fourth antinomy

The fourth antinomy has to do with the existence of a first cause. Thesis: "In the series of world causes there is some necessary being". Antithesis: "There is nothing necessary in the world, but in this series all is contingent." Kant recognizes the objections raised by Hume in his Dialogues Concerning Natural Religion, where it is pointed out that we can not attribute qualities to the Supreme Being (such as understanding or will) because we can only do so by attributing anthropomorphic qualities to a being whom we cannot assume has them. Since we have our idea of will or of understanding only by reference to ourselves, we are not justified in assuming that God is like man. Kant says that we can refrain from doing this by using analogies. For example, although we cannot assume God to have rationality in the same way that we do, we can say that there is a rational structure to the world, and that

"reason is attributed to the supreme Being so far as it contains the ground of this rational form in the world, but according to analogy only, i.e., so far as this expression shows merely the relation which the Supreme Cause, unknown to us, has to the world in order to determine everything in it conformably to reason in the highest degree."

So although we may not be able to attribute properties directly to God (or a supreme being), we can attribute properties indirectly by way of analogy- by attributing properties to the relation which God bears to the world.

Kant- The third antinomy of pure reason

As for the second two antinomies, Kant says that the dialectically opposed propositions of each contradict one another only if one takes appearances (phenomena) to be things in themselves(noumena). The thesis of the third antinomy is as follows: "There are in the world causes through freedom". The anthithesis: "There is no freedom, but all is nature". This is the same question that Hume took up when he considered liberty and necessity, except that Hume solved the problem by defining free will in a way that is compatible with determinism. Kant doesn't take that approach. Kant approaches the problem by asserting that one can actually be the first cause of a causal series, even if natural causal necessity exists. He does this by saying that the natural necessity of causality is part of the world of appearances, that is, the world of space, time, change, and natural law. While the phenomenal world requires there to be a cause for each event, the noumenal world can have what Kant calls 'spontaneity'. Spontaneous causes are uncaused causes. How is this possible? It is possible only through a will that acts according to rationality. Because the prescriptions of rationality are independent from time and change, acting according to rationality is acting according to something independent of the phenomenal world. The phenomenal world would still retain the appearance of a prior cause, while in the world of things in themselves an action can be spontaneous.

Kant: Pure mathematics

According to Kant's distinctions, one would think that a single proposition should fall into one of four categories: (1) a posteriori/synthetic, (2) a posteriori/analytic, (3) a priori/analytic, and (4) a priori/synthetic.

The first category contains propositions which we come to know through experience and provide us with new information (the predicate is not contained in the subject). They are usually uncontroversial, but can be subject to interpretation. This is a big category--it contains statements such as "all bachelors drink beer" and "the president is dishonest." Here, the predicates are not contained in the subjects, and you would not be able to determine them without experience. The second category is mostly empty because it implies that we come to know a proposition whose predicate is contained in its subject through experience. There would be no reason for one to appeal to the senses for an explanation of something that is self explanatory. The third category includes logical truths that are necessarily true. So, for example, A=A. The predicate is contained in the subject, and the proposition can easily be known before any sort of sensory experience. The fourth category is the complicated one. It suggests that we may come to know a proposition that provides us with new information through reasoning alone. Kant asserts that geometry and arithmetic fall under this category.

Kant: analytic vs synthetic

Kant's next distinction is between analytic and synthetic judgments. This distinction is determined by the information contained as their content. In analytic judgments, the predicate is wholly contained in the subject. Analytic judgments do not really provide us with any new information. Kant's example of an analytic judgment is "all bodies are extended." It is contained in the definition of a body that it is extended in space, so we really do not receive any new information from that statement. Analytic judgments, like a priori information, are universal tautologies. Synthetic judgments, on the other hand, do provide new information. The predicate in one of these judgments is not contained in the subject. Kant's example is "all bodies are heavy." The predicate of "heavy" is not implied by the subject of "bodies." So, if someone just started talking about bodies, you would not immediately associate the word "heavy" with those bodies. Any connection between the predicate and the subject in a synthetic judgment is distinctly external to both. Therefore, even though synthetic judgments turn out to be informative, they do require justification. For simple purposes, I think that Kant's distinction will come in handy, but I think that the classification of one proposition may vary from person to person.

Kant: a priori vs a posteriori

Kant devotes a lot of time to drawing distinctions between different kinds of judgments that we make. The first distinction that he makes is rather simple, and that is the distinction between a priori and a posteriori judgment. The distinction comes from the origin of the information that we obtain. A priori (literally "from what comes before") information is determined by reason alone and can be found out without any particular experience. This makes a priori information universal tautologies. A posteriori (literally "from what comes later") information, on the other hand, requires a certain experience in order to obtain that knowledge. The information obtained, therefore, is limited and subject to interpretation. Kant, who blends rationalist and empiricist theories, says "that all our knowledge begins with experience there can be no doubt... But... it by no means follows that all arises out of experience." I agree with Kant on this point, because we are not born with knowledge about mathematics, colors, or really anything else. But, with simple lessons here and there through experience, we can learn how to rationalize and reason through problems we have never encountered. So, for example, I can figure out what 29381818291301 plus 3181029138104 equals, even though I have never experienced that problem before. However, I need the prerequisites of knowing how to count and add in order to reason myself through the problem.

Hume: Missing shade of blue

Hume, as an empiricist, believes that any idea in the mind is really just an impression of something that was experienced through the senses. His example of the missing shade of blue, then, bothers me because it exactly disproves that idea.. and he agrees that it is a counterexample to his theory, but he doesn't seem to care. Assume that a man has seen every shade of every color in the world, except for one particular shade of blue. Pretend that this man is shown a series of cards, each of which has a shade of blue that he has previously experienced, and the cards are presented in order from lightest to darkest, with the exception of a blank card representing the shade of blue he has never seen. Would the man be able to imagine what that shade of blue would look like? Hume says yes, and I would agree with him. The man could infer that the missing shade is just a bit lighter than the card to its right, and just a bit darker than the card to its left. What bugs me about this is that Hume admits that the man would be able to figure that out, but that's in direct opposition to his basic arguments as an empiricist. The excuse Hume gives is that the example is "so singular that it is scarcely worth our observing, and does not merit that for it alone we should alter our general maxim." I don't see why that is justified, because the missing shade of blue seems like a perfectly legitimate objection to his arguments. Hume kind of just dismisses it instead of tackling the problem.

Hume: Moral Responsibility

Part of Hume's version of compatiblism involves moral responsibility. Hume says that his compatibilism works with holding people morally responsible for their actions. He says human behavior falls in line with the natural chain of cause and effect. If this were not the case, then human behavior would be subject to randomness. Praise and blame are only justified, according to Hume, if actions are performed as a result of a person's character. I agree with Hume on this point, because if everything was random then we wouldn't be able to hold people responsible for their actions. If John murders his family, we cannot punish him because it was purely an act of randomness (this kind of reminds me of when people plead insanity and things like that--they couldn't help what they were doing or didn't understand the consequences of their actions). From here on out, however, I'm a little confused about Hume's argument. He goes on to say that we can justify praise and blame with determinism, and that in turn justifies freewill. That all seems a little out of order to me. First of all, Hume's earlier description of what justifies praise and blame sounded to me like freewill---if people can freely make the decision to murder their families, they should be blamed for it. If it was determined that an individual was going to murder his family, should he still be held responsible? Because if the act was determined, then he could not have done anything to stop it. So I don't think that determinism entails holding people morally responsible. I might agree that if determinism DID entail holding people morally responsible, then we could figure that we do have freewill. But Hume didn't argue for anything like that, so yet again, I disagree with him.

Hume: Compatibilism Pt 2

The only explanation that Hume gives for compatibilism is that both free will and determinism appear to be true. He defends determinism by saying that the chain of cause and effect in nature is inevitable, and everybody acknowledges that it is there--it is part of human psychology. He defends freewill by saying that we appear to freely do things that we are capable of doing. So, as long as you're not in chains or restricted by drugs or anything else, you have freewill. My problem with that, as I've stated in earlier posts, is that you can't really know that you're making those choices and doing those things freely. We can't prove that those things aren't part of the whole grand scheme of determinism. If we could go back in time, maybe we'd have a shot at proving or disproving that, but obviously we can't. But anyway, Hume does not address how determinism and freewill might work together. He just argues for determinism, and then argues for freewill. Since he has reasonable arguments for both, he decides that both are true and they work together. So if I'm going to agree with his theory of compatibilism, I would only have to agree that both determinism and freewill are true, without acknowledging how they might work together and all that. Obviously since I'm not convinced by his argument for freewill, I'm not convinced by his version of compatibilism. It seems to me like he kind of took the easy way out of this one because he liked the idea of compatibilism but didn't have any good arguments for it.

Cosmological Ideas 3 & 4

In in third part of Proglegomena, Kant discusses cosmological ideas, which he separates into four different arguments. The third and fourth are:

3. The claim that we can act in accordance with our own free will vs. the claim that everything we do is determined by nature.

4. The claim that there are necessary causes vs. the claim that nothing is necessary and everything is contingent.

Kant says that in 3, causal necessity and freedom are made to seem contradictory when in fact they are compatible. He says that the laws of nature are applicable only to appearances since they can only operate within the limits of space and time. He says that freedom is only applicable to things in themselves because it is the ability to exist outside the confines of experience. He says that we can be free and also be subject to the laws of nature because our faculty of reason does not deal with experience and so we are free in our capacity as rational beings. The freedom has to express itself in and only in general maxims that do not depend on causal influence or particular times and places, so we still follow the regular laws in the world of appearances.

In 4, the contradiction is resolved somewhat like 3 is. He says that half of the proposition talks about things in themselves and the other half talks about appearances. He says that every causal connection may be contingent in the world of appearances, meaning it could have happened otherwise, but these appearances might have a necessary connection to things in themselves.

Cosmological Ideas 1 & 2

In in third part of Proglegomena, Kant discusses cosmological ideas, which he separates into four different arguments. The first two are:

1. The claim that the world has a definite beginning and end vs. the claim that the world is infinite

2. The claim that all things are made up of simple, indestructible, indivisible parts vs. the claim that everything is composite and infinitely divisible

Since these claims cannot be proved with experience, we tend to think they deal with things in themselves rather than with appearances. Kant does not attack either side, instead he shows what mistakes come about in each one. He says that the mistake in the first one comes from treating space and time are features of our experience, and do not exist independently of experience. He says that it does not make sense to asked if the world has a limit in space and time since the limit would exist where we would not experience it.

The problem with the second argument, according to Kant, is that when we talk about the parts into which a composite thing can be divided, we are assuming that these parts already exists inside the composite thing, but they are only appearances, so they cannot have any existence until the are experienced.

Psychological Ideas

Kant says that psychological ideas attempt to identify some kind of substance or an ultimate subject that underlies all the predicates we can apply to a subject. He says that this is pointless because the understanding helps us make sense of experience by applying pure concepts to empirical intuitions and concepts take the form of predicates. So knowledge comes in the form of predicates attached to subjects. Kant says that we can consider the ego or soul as an ultimate subject because we refer to an "I" when we describe any internal state, but he says that we cannot have knowledge of this "I" in itself. The fact that we are capable of experience suggests that we have consciousness, but we refer to it without having any ample knowledge of it, we can know nothing about our consciousness, we can only know about appearances. All that we can say about our consciousness or "soul" is in reference to our own experience.

Kant- The Pure Intuitions of Space and Time Pt. II

Given the considerations in my last post, we can begin to understand why Kant believes that we can have a priori synthetic knowledge (that is, a priori knowledge that adds to our knowledge, ie. certainty of the necessary connections of cause and effect, etc.). Kant says that "Geometry is based upon the pure intuition of space. Arithmetic attains its concepts of numbers by the successive addition of units in time". (Prolegomena Part I) Kant says further that "Sensibility, the form of which is the basis of geometry, is that upon which the possibility of external appearance depends." There are grand implications which follow from this statement in Kant's metaphysics. The implications are basically that our experience of space must conform to the same rules of sensibility that geometry conforms to.

Lets take an example: Kant says that the reason that there are only three spatial dimensions is geometrically based. Kant says that this is because not more than three lines can intersect to form right angles at any one point. This can be illustrated( or maybe intuited) by using the Cartesian coordinate system. Imagine an x and y axis, one for length and one for width. They intersect to form right angles. Now you can probably imagine a third axis, the z axis, which would represent depth. This line also forms right angles with the first two (you can visualize this by drawing a cube). Now if you try to figure out how to add another line which forms right angles through the same point, you will see that you cannot. It is a geometrical rule that no more than three lines can intersect to form right angles at any one point, and it is this rule to which our experience conforms. In fact, the possibility of our experience rests on its conformity to the pure intuitions of sensibility.

Kant- The Pure Intuitions of Space and Time

Kant believes that our experience is first and foremost experience of appearances (those which he calls 'phenomena') rather than things in themselves (or 'noumena'). Kant explains that all of our experience requires space and time. This seems fairly intuitive. Kant goes further. He says that space and time is not a property of things in themselves but rather the pure forms of intuition that make possible the world of appearances. This is another way of saying that space and time are not given to us by experience but rather that they are a priori categories of pure understanding which exist in the mind. Being a priori, they are prior to any sense experience. Now, a hardcore empiricist might here object with the slogan "nothing is in the intellect which is not first in the senses." But Kant might have the empiricists beat here. If we require space and time in order to experience anything at all, then space and time must be prior to the experience of any objects which exist in it. This is not to say that space and time exist temporally before any objects do (this would seem strange because there would have to be space and time without objects, which is arguably absurd), but rather that space and time are ontologically ('ontological' here means 'concerning existence or Being') prior to the appearance of objects in that space and time are necessary conditions for the having of experience.

Hume’s mistake according to Kant

Kant talks about Hume’s mistake in not understanding the nature of experience. Like many before Kant including Hume, believed that experience is simply a set of impressions. Thus ideas and impressions are constructed by compounding simple impressions. Kant would say that these are sensations, things we take in by our senses. Kant then argues that experience is more than these simple impressions and it all happens in space and time. Kant says that space and time are not impressions or sensations because they are pure intuitions. Thus everything that happens in time and spare are bound by the laws of cause and effect. Cause and effect in this case are also not impressions but rather concepts of understanding. So intuitions and concepts combine to make an orderly experience for us to understand.

Descartes Cogito argument

In the second meditation Descartes starts out by doubting everything the world around him, his memories and perceptions and so forth. He even starts to wonder about his own existence until he come up with probably the most important and influential statement in philosophical writing the Cogito argument. Descartes starts to think about his existence and everything else’s existence and comes to one important conclusion. That if he is able to doubt his existence then he must exist in at least some for. Even if a demon or divine deceiver was tricking you with what you say, heard, tasted, touched and so on was fake he himself is some form had to exist to be able to think these thoughts. So out of this pondering of existence comes the famous line “I think, there for I am”.

Cause and Effect

In the second part of Kant’s book he talks about how can not know the concept of cause and effect either through experience or reason. Kant does not agree with Hume that this is considered habit or custom that rather it is a priori knowledge that we apply to appearances. We are not able to know things as for what they are; we are only able to understand them by the appearances that are given off by them. Kant says that cause and effect is not to found in the appearances but rather in the form of the object and the understanding given by it. Hume like Kant both agree that we con not derive concepts from experience but instead we derive experience from those concepts. Concepts of understanding allow for us to legitimize experience, though it still can not tell us anything about the objects or things themselves. This helps us make connections between appearances but they can not go any farther than those appearances given off.

Judgments of Perception vs. Judgments of Experience

In the second part of the book Kant talks about the distinction between judgments of perception and judgments of experience. Judgments of perception combine together all our empirical thoughts and are only subjectively valid. So take the example of how I might notice that the sun is shining and then realize how the rock is warm. I might come to the conclusion that because the sun is shining the rock is warm, though this is valid only for me at this specific time.

Then Kant goes into talking about judgments of experience, these apply “concepts of the understanding” to judgments of perception. This is taking the previous example and taking it one step further, by adding cause to the argument it allows for us to be able to understand natural laws. Like before the sun is warm which in turn causes the rock to heat up and feel warm. Kant then goes on to say that we use judgments of experience to structure how we understand experience. Kant goes into talking about how judgments of experience are a priori concepts we combine together to understand our judgments and that these a priori laws allow for natural science to exist.

A priori vs. A posteriori

In the first section of Proglegomena, Kant discusses the distinction between a priori and a posteriori knowledge and how it shows the two possible sources of knowledge, the intellect and experience. He says that a priori means that we know something independently of observation and a posteriori means that we know something through observation. He claims that math is an excellent example of a priori knowledge since we can figure it out in our heads and nothing we experience can contradict this.

Understanding vs Reason

In the third part Kant talks about the difference between understanding and reason. He says that this is a big problem that arises in philosophical thinking. Hume says that any concept that can be associated with experience belongs under the category of understanding. While when we use reason we are striving not to use experience, experience only causes problems in reasoning. Kant comes up with three different ideas of reason, psychological ideas, cosmological ideas, and the theological ideas.

Looking at psychological ideas we are trying to find some sort of thing or subject that is underlying all the predicates we apply to the subject. For example when looking at a fish we may say the thing with scales that thing that lives in water and so on, but what is the thing. Kant says that this is worthless and just wasting time. These things help us understand things by allowing us to apply concepts to empirical intiotions and concepts take the style of predicates. The cosmological idea is simply an idea thats object can not be used in any experience. Basically that we use reason to prove four thesis and antithesis about the world and how it is. Lastly the third type is theological which unlike the other two do not start from experience. We start rather with the idea of pure completness of a thing (a perfect being) to determine the possibility and thus the actuality of all other things.

a prior and a posteriori cont...

In the book Kant goes a little further into the distinction between a priori and a posteriori and analytic and synthetic judgments. According to Kant All analytic judgments are a priori, this is because they are in the breakdown of the concept itself. While synthetic judgments can either be a priori or a posteriori. Kant then goes into classifying synthetic judgments into three types, judgments from experience, mathematical judgments, and metaphysical judgments.

Simply put judgments from experience are a posteriori because they are just the combining together objects of experience. This would be taking into effect what had happened in previous experiences to judge what is going to happen in this case. Mathematical judgments are a priori judgments. Kant says the concept of 7+5 contains the idea of the two numbers but does not contain the idea of 12. We have to think about it and associate the two numbers with the idea of 12. Lastly metaphysics also consists of synthetic a priori judgments since metaphysics is made up largely of analytic judgments since these are the only things that metaphysicians can agree upon. Though there are synthetics judgments that are built upon these analytic judgments.

a priori and a posteriori

In the summary of Kant's book he gives a description between the differences of a priori and a posteriori knowledge. A priori knowledge according to Kant is anything we derive from pure reason while a posteriori knowledge is things we derive from experience. He then goes on to draw a even more important destinction between analytic and synthetic judgment. According to Kant the predicate of the analytic statement is in the object itself. For example all bachelors are unmarried men. It contains in the word bachelor that they are unmarried men and does not add anything to the statement. While the predicate of the synthetic on the other hand adds something to the statement. For example all swans are white you may not know before hand that all swans are white. So by hearing this information you gain some information about the idea of swans.

Philosophical vocabulary

In the later part of section 2 Hume talks about the philosophical vocabulary between the term impression and the term idea. As he states earlier in the section for the use of the words an impression is are clear and exact, things that we percieve with our senses, taste, touch, and so on. Ideas are less vivid, faint and some times obscure and unlike impressions we are likely to suffer error in remembering them. So when talking about an idea in philosophical terms we may ask by what impression did this idea come from. If it were to not come from an impression it would then be useless and meaningless.

Shades of blue

In section 2 Hume talks about a contradiction between ideas and impressions. Earlier he talks about how impressions are the things we see, hear, smell and so on. Basically everything all things that we perceive through our senses. While ideas are the compounding of these impressions like remembering how and apple tasted or looked (remembering the color). In this contradiction Hume talks about how if he had seen a few shades of blue he believes he could imagine other shades of blue without ever seeing them.

I am not completely sure about this idea, maybe we could imagine some different shades in which we believe we have not seen. Though i would have to say that we probably did see those shades in some form someone else before and just did not remember it. So i would still have to say that we could not imagine something that we have not seen before.

Relation of Ideas vs Matter of Fact

In section four Hume talks about the distinction between "relations of ideas" and "matter of fact". According to Hume relations of ideas are a prior knowledge. These type of things would include all logical statments like all "men are batcholors" and 6+6=12. He then goes on to say that relation of ideas are certain and can't be thought of different, if you were to it would be a contradiction. It like saying 2+2=5 or 2+2=chair we know that is wrong just by the simple idea of relations of ideas thus we know 2+2=4.
Hume then moves on to talking about "matters of fact" which deal with experience. Matters of fact are things like the sun is shining, it is going to storm tommarrow, these are things we learn posteriori. These are also things in which we do not fear because of contradiction. So if i were to say there is a clown outside, it is pretty easy for someone to go outside and see if there is or not and prove me wrong. Hume also talks about how we know matters of facts about things in which we have not observed through a process of cause and effect. I know that my friend is in France though i have not seen it myself, through a letter i can draw that conclusion.

Causation

In the latter sections of the second part, Kant discusses Hume's ideas about causation. He says that Hume was right when he said that we cannot comprehend the possibility of causality by reason or experience, but he does not feel that this concept is the result of habit or custom. Kant says that maybe we can only know how things appear to us by the form that our senses give to those things and that we know nothing about these things in themselves. Kant is basically saying that experience is more than simple impressions and that everything we experience happens in space and time and they are not impressions or sensations; they are pure intuitions.He goes on to say that pure intuitions and concepts organize experience for us and give it form.

I like how Kant seems to find a middle ground between the empiricist and rationalist views by saying that we can have a priori knowledge relating to experience and that this knowledge does not tell us anything about things in themselves. He says that innate faculties give form to what we perceive and that even though they determine the patterns according to which the world appears to us, they do not tell us anything about what the world is really like.

Judgments: Perception vs. Experience

In the second part of Prolegomena, Kant discusses the difference between judgments of perception and judgments of experience. He says that judgments of perception are only "subjectively valid" and that they "only require the the logical connection of perception in a thinking subject." (sect. 18) He goes on to say that all of our judgments are "at first merely judgments of perception; they hold good only for us." (sect. 18) Kant then discusses judgments of experience and says that if they have objective validity, then they are empirical judgments. He says that those judgments always require special concepts originally generated in the understanding, which make the judgment of experience objectively valid.

Kant is basically showing the difference between things in themselves and our perceiving mind. Judgments of perception are joining and associating two or more intuitions with each other and making a connection between them. They deal with our senses. He says that we turn judgments of perception into judgments of experience by using concepts of pure understanding because empirical intuitions in themselves cannot be generalized.