Well, one problem (I wouldn’t call it an argument really) as I see it in Kant’s Critique of Pure Reason is his distinction between a priori and a posteriori knowledge.
Since the majority of our perception of the world comes entirely from experience, then all (or most) knowledge originates a posteriori; and really, there is no true a priori knowledge.
Kant’s definition of what constitutes a priori knowledge (knowledge that is independent from experience) sort of implies to me that all a priori knowledge must have first originated as, or been extracted from, a posteriori knowledge.
Even supposed “a priori knowledge” as simple as 2+2=4 relies on experience. When we think of “2+2=4” our brain unconsciously confirms this knowledge with memories (from math class in school or whenever the individual learned that 2+2=4) which originated through experience. However, over time, the collective memories associated with mathematics have accumulated, and in turn, they have been permanently ingrained and integrated into our mind’s perception of the world - once this integration occurred, it was no longer necessary for our mind to recall specific incidences where 2+2=4, and instead the concept of 2+2=4 (and other mathematics) became an independent mental process which we could apply to anything we needed to.
Hence, a priori knowledge is extracted from a posteriori knowledge.
Now, new problems emerges in Kant’s theories:
- Since all knowledge originates from experience, and since experience has proven that from time to time it is inaccurate when creating our perception of something, then how can we ever conclude that their exists a true and absolute a priori knowledge? For example, centuries ago, most of humanity was under a firm impression that the world was flat; they would have considered this “a priori knowledge”. They would have thought “certainly their are geographic anomalies in the flatness of the world such as mountains and valleys, but all landscapes as a whole are set on a flat plane”. However, we know this now to be false, we know the Earth is round. But just as people several centuries ago were absolutely certain that the Earth was flat, are there not similar situations in the minds of modern humanity? - Situations where we believe something to be “true a priori knowledge” but due to our limited perception of the world, we are unknowingly wrong.
From that problem, the definition of “a priori” becomes “knowledge which must be true, since the variables involved verify each other”. For example, the statement “All bachelors are unmarried” is a priori knowledge since “being unmarried” is part of what constitutes the definition of a “bachelor”. So, “2+2=4” fits this definition of a priori, since the value of “4” contains within it “2 sets of 2” - “4” is four parts, and “2” is “two parts” - so two groups of two parts would have four parts total.
However, even this definition of a priori will run into problems. It relies heavily on the context in which the knowledge is being stated. For example, we could consider that “Water = H2O, that is, two hydrogen atoms bound to one oxygen atom” is a priori knowledge. However, this relies on context. For if you were to pour a glass of water out of the water faucet, and if you were to check to make sure there were no specs of dirt or any visible debirs of any kind, and claim “There is only H2O in this glass” you would technically be incorrect. There would be other minerals and molecules that are invisible to the human eye within the water, such as fluorine, calcium, and sodium, as well as other microscopic debris (dust particles, bacteria, etc) that you could not see. Therefore, there is a lot more than just H2O in water. Even distilled water still contains some contaminants. So how could we say “Water=H2O” is a priori knowledge? We must rely on the context of the words. Does the context of “water” include everything within the liquid which we consider water? Or does the context of what is considered “water” only include H2O molecules?
Even “2+2=4” relies on context, since really, the problem 2+2=4 is just symbols - seemingly arbitrary patterns on a computer monitor. What if one individual’s definition of “2” was actually our definition of “3” - that is, the individual’s definition of the symbol “2” is “a value of three parts”? In that case, 2+2 would not equal 4, it would equal 6.
Since we obviously must incorporate a slight amount of “lee-way” into our definition of “a priori” to account for varying contexts, then the problem re-emerges: How can there ever be true a priori knowledge?
We can only assume that “true” a priori knowledge exists, and even once we have determined something to be “a priori” knowledge, we must be skeptical of it.
We could say that a priori principles are “Universally Accurate Principles which are Independent of the Human Mind”, and that a Human mind can never truly grasp the awareness of an a priori principle - at most, the human mind can only perceive an imperfect reflection of these principles which are in some way flawed by personal experience.
And even these “Universal Principles” (such as the fundamental forces like gravity, or mathematics and euclidean geometry) are only virtual principles. The principles may change to accommodate for other principles or fluctuations/anomalies within the principle itself. Instead of being “real” and “absolute”, these principles only exist as virtual “tendencies” of how the universe tends to behave. For example, all matter has the general tendency to gravitate towards other matter, but this principle is bent/altered to accommodate for incidences such as the bending of the space/time continuum.
Even the concept of “2+2=4” can not be an absolute principle (even given that the human context is accurate), and only exists as a general tendency. For example: We could say that if you have a group of 2 sheep and a group of 2 pigs, then you have 4 animals altogether. However, what if one of the sheep is pregnant? Then would we count the sheep inside of the womb as additional animals? What constitutes an “animal”? Should we include the parasites that reside within the sheep’s fur? Even if we were to imagine a scenario with minimal variables, such as, “If we have two hydrogen atoms, and two helium atoms, we have four atoms total” this would still encounter logical problems. For example, what constitutes an “atom”? Since a “proton” can be considered an atom by itself (a hydrogen atom is just one proton), then there are actually six atoms total since their are two protons in each Helium atom.
However, due to quantum uncertainty, we can not even determine the accuracy of this simple scenario. Since it takes time for information to travel (information can only travel as fast as the speed of light), then we could never be absolutely certain that there truly exist “4 atoms total” in a grouping of 4 hydrogen atoms. At any given moment, the hydrogen atom could hypothetically bind to another molecule and cease to be a hydrogen atom anymore. If the value of “4 atoms total” implies “4 atoms total within a given perimeter”, then at any moment, another atom could enter the perimeter and there would be 5 atoms instead of 4. Or, at any given moment, one of the hydrogen atoms could decay (although protons are incredibly durable and could be considered indestructible; a proton’s decay has never been observed in any scientific experiment to date; they are estimated to ‘live’ indefinitely or until the destruction of the universe, or after an incredibly long time (something within the ballpark of 10^36 years)). At any given moment, the process of “electron capture” could take place and one of the hydrogen atoms could transform into a neutron.
Therefore, there is no realistic situation where a priori knowledge (even as simple as 2+2=4) can be absolutely true. At most, a priori knowledge only exist as virtual tendencies. Absolute a prior knowledge can only exist as a hypothetical representation within the human mind, and the variables involved can only be relative to other variables within the same representation.
Since theories such as “Quantum uncertainty” were not around when Kant wrote his Critique of Pure Reason, his conclusions were fairly accurate given the context of 18th century Germany/Prussia. However, they really do not amount to anything more than “There exists knowledge, called a priori, that is independent of experience (which is a posteriori), although what constitutes such knowledge is difficult to grasp and has no practical application other than its recognition”.
I’ll have to refresh my memory of Kant’s Critique of Pure Reason and then reply, but from what I remember, he spends most of illustrating the distinctions between a priori and a posteriori, only to fail at finding any practical applications for such conclusions. His conclusions rely heavily on context and subjectivity. From what I remember, the only reason he went through the time and effort of illustrating such distinctions was so that he would be better able to disprove his contemporaries. Basically, he created a reference point off of which to base his criticism of others; it is his self-created argumentative tool.
I can’t say this for sure, but I wouldn’t be surprised if he would use his conclusions in an argument much like the ancient Greek sophists would persuade others: “How can you be so sure of something like that? Your evidence relies on personal experience and therefore can not be proven as true.” to the Greek sophist equivalent:
Opponent: claims point A
Sophist: “How can you know for sure?”
Opponent: claims evidence supporting point A
Sophist: “How can you be sure that the evidence is true?”
Opponent: claims evidence supporting the evidence for point A
And the argument continues in the same pattern with the sophist providing possible counter-evidence when possible. Most of the time, it ultimately resulted in the sophist’s opponent having to prove his own existence (or that existence even exists), and the sophist would point out that his opponent can not know anything for certain, and therefore he shouldn’t say his conclusion with such certainty.
Kant could have saved himself a lot of time by just saying “The world outside of your mind is different from the world you perceive”, but instead, he created a complex system for “verifying knowledge” that was really no different than common sense. In a sense, he attempted to map out the mechanics of “common sense” that could be used as a foundation for all other knowledge.
His “Critique of Pure Reason” is really not as significant as people give it credit for, and Kant’s ethics are by far his most significant contribution to philosophy.
Kant’s style and attitude was “I have to be able to prove my conlcusions with absolute certainty, or else they are nothing at all” - however, since “making conclusions with absolute certainty” isn’t a very realistic task to undertake, the net effect was that it gave his philosophy a dull, monotonous, boring, non-artistic and blunt tone. Since he declared things with such certainty, it would prompt readers who have an inherently rebellious attitude to try and point out flaws in Kant’s works. Since his rhetoric could be considered “bland”, it causes readers (who have a neutral view on Kant) to be bored and their general tendency is to not agree with it. This prompted a lot of criticism from future philosophers (such as Schopenhauer in “The World as Will and Representation” and Nietzsche). Ironically, most of his fans were also his critics.
The exception of course is readers nowadays who have a predisposition to Kant’s philosophy (they have heard good things about it so in turn they expect good things) and they actually want to like it; it is a self-fulfilling prophecy. Kant is essentially “put up on a pedestal” by his fans because:
A) It was written a long time ago, so any mistakes the reader’s find in his writing is compensated with the expectation of not being able to understand some of the writing due to an old context.
B) If it was written a long time ago by an old person, it must be true. (This is considered a fallacy since the age of something does not determine its validity).
C) Because he provides “guidelines” for understanding - most of the audience for all philosophy is attracted to writing which provides “guidelines for knowledge”, since this essentially allows for the reader to feel privileged among other people - it is good ego support (and rightly so haha).
German intellectuals accepted Kant’s philosophy by storm, arguably because the stereotypical “German” (especially in the past) has virtues such as pride, and they admire those who boldly display power. In a sense, they had mistaken Kant’s style as a “bold display of power and righteousness”, or at least that is what they perceived it as.
Basically, his work became inadvertently popular.
Is Kant’s work truly as significant as its reputation would lead us to believe? No.
Is it still interesting none-the-less, and a substantial contribution to the history of philosophy? Yes.
