kripkenstein's quaddition - exposition

oh kripke... or kripkenstein.. or whatever...

so here's the real deal. i have not read wittgenstein's philosophical investigations so take this entire post with a grain of salt--or a heap of it.

anyway the argument as it struck kripke goes somewhat like this:

suppose you've never performed the mathematical function "plus" with integers greater than 50. A is a teacher and YOU are B.

A: "17 plus 23 is..."
B: "40"
A: "yes! you got it! now, 58 plus 67 is..."
B [takes a bit longer. B computes in his head] "125."
A: "uh... i'm sorry. i don't think you understand. try again."
B [computes again]: "no i did it again in my head and.. well i was right. it's 125."
A: "uh... i think someone didn't teach you this right. 58 plus 67 is 5."
B: [baffled] "whaatt??"

so here's the trick. when you heard the word "plus" you thought that was a function where you combine numbers , such that

'plus (a,b)' = addition (a,b) --> 'a + b' when {x| -∞, ∞}

however, it is not logically inconsistent that "plus" really referred to the function of quaddition such that

'plus* (a,b)' = quaddition (a,b) ---> 'a+ b' when {x| -∞, 50} and '5' when {x| 50, ∞}

now, it's important to note that this skeptic who is proposing this skeptical scenario is not being a skeptic about the concept of addition. he's not saying that the concept of addition is vague in any way. he's just saying that it's not logically inconsistent to propose that it may be the case that whenever we use the word "addition" or the mathematical symbol of "+" we might be talking about quaddition instead of addition.

this skepticism, however, is not just an epistemological skepticism about whether we know we're adding or quadding, but it extends to a metaphysical skepticism about our own use of concepts. we can think we know what concept we're using but we could be mistaken.

i'm interested to see how or if kripke attempts to solve this...

constructive empiricism and its discontents

‘[A] realist is simply one who knows no more recondite reality
than that which is represented in a true representation’

-Charles Sanders Peirce

(CP, 5.312. Quoted from Haack 1998: 35)

I. Introduction

In The Scientific Image, Bas van Fraassen has given us all another answer to the question ‘What is science?’(Van Fraassen 2001: 151) He names his answer ‘constructive empiricism’ and it is meant to be an alternative to the standard scientific realism. This new account, to my understanding, is a view that allows for the success of scientific theories only as empirically adequate, without any ontological commitment to unobservable entities. Although he does not deny their reality, he argues that we are not in any epistemic position to believe in them. There are many instances where I believe his arguments are flawed, and I will point some of them out. None of my objections will be definitive, but nevertheless I will argue that because scientific realism is both the pre-philosophical position and that of many scientists themselves, the burden of proof falls on van Fraassen to provide a successful alternative, something I believe he does not do. In the paper, I will first give a sketch of constructive empiricism as a freestanding ‘view’ of science, and then I will outline the main objections to the theory. My conclusion will state that constructive empiricism, although a theory that must be addressed very seriously, will not convince a strong-willed scientific realist because it (constructive empiricism) is itself subject to many of the same criticisms scientific realism is subjected to. However, the main aim of this paper is not to offer a positive defense of SR, just to create enough belief in the inadequacy of constructive empiricism that, if done well, the reader has some serious doubts about it.

II. Constructive Empiricism

Constructive empiricism is best understood as an alternative to scientific realism’s characterization of science. To van Fraassen, a scientific realist would agree to saying that ‘[science] aims to give us, in its theories, a literally true story of what the world is like; and acceptance of a scientific theory involves the belief that it is true. (van Fraassen 1980: 8)’ To van Fraassen, then, a scientific realist would agree that science makes assertions about the world which are literally true (i.e. these assertions attempt to genuinely refer to real objects and laws in nature), and that to accept a scientific theory is to believe that those objects and laws referred to are real. The main intuition motivating van Fraassen is that (1) sometimes scientific theories attempt to refer to objects we, as humans, cannot directly observe; (2) if we cannot observe something directly, we are not epis-temically warranted to believe in its truth; therefore (3) we are not warranted to believe in the reality of unobservable entities posited by (or assumed in) scientific theories.

Because of this problem of unobservables, van Fraassen is forced to give us an alternative example of what exactly science is. At this point, van Fraassen breaks with pre-philosophical notions of the nature of science. Scientific theories, presumably, make statements about the world. These statements can either be true or false, depending on how the world is, no matter if the entities posited are observable or not. However, van Fraassen returns with a challenging rebuttal: ‘Science aims to give us theories which are empirically adequate, and acceptance of a theory involves as belief only that it is empirically adequate. This is the statement,’ van Fraassen says, ‘of the anti-realist position I advocate (van Fraassen 1980: 12).’ But this may then lead to the obvious question: what is it for a theory to be empirically adequate? To van Fraassen this means that a theory must ‘save the phenomena.’ In other words, a theory’s most tantamount purpose is to accurately describe the observable consequences of its acceptance. So there you have it. It is true that science may posit the existence of unobservable entities in many of its theories, but the main (if not the only) aim science has is to provide empirically adequate theories for future predictions of observable phenomena.

As Ladyman has pointed out (2000: 840), the anti-realist position van Fraassen offers is epistemic, not metaphysical. In fact, he believes we ought to recognize objective ontological existence to objects that are actually empirically observable. He believes, however, that the empiricist must ‘withhold belief in anything that goes beyond [that]’ (van Fraassen 1980: 202). So, prima facie, van Fraassen seems to be sitting on the fence between agnosticism and atheism about the posited unobservables in our best scientific theories. However, he does mention at various times that believing in the entities proposed by scientific theories is not irrational, just not supported by empirical observation. Here van Fraassen introduces the distinction of empirical and superempirical virtues, where an empirical virtue is the only warranted epistemic virtue, and characteristics some theories have, such as explanatory power, elegance, parsimony, and coherence with other theories are merely ‘superempirical’ virtues that provide pragmatic reasons for their adoption.

Because constructive empiricism states science’s aim is to achieve empirical adequacy, constructive empiricists are left to explain explanation itself and its role in this alternative view of science. Many scientists believe explanation or nature is the ultimate goal of science. Moreover, whether or not the main goal of science qua science, explanatory power plays a major factor in theory choice. So if van Fraassen decidedly denies this, he is forced to provide an alternative account. Specifically, he must provide an account for the role abduction (or inference to the best explanation) has in science. In order for constructive empiricism to be an accurate account of the goings on of science, abduction must be denied as a legitimate rule of inference because it oftentimes appeals to unobserved or unobservable phenomena. So instead, van Fraassen insists abduction is a pattern of thinking that goes beyond what we’re epistemically warranted to make. Much like induction, van Fraassen says that he who uses abduction ‘is not thereby irrational. He becomes irrational, however, if he adopts it as a rule to do so, and even more if he regards us as rationally compelled by it’ (van Fraassen 1989: 132 from Ladyman 2002: 223). So, to van Fraassen, one has to make abduction at least as questionable as induction, although, as I will show later, he might be using an abductive argument himself when appealing to this claim.

It is possible to characterize constructive empiricism as a reaction to the strong underdetermination argument for scientific theories. (Ladyman 2002: 174) characterizes the argument as follows:

1. ‘For every theory there exist an infinite number of strongly empirically equivalent but incompatible rival theories.

2. If two theories are strongly empirically equivalent, then they are evidentially equivalent.

3. No evidence can ever support a unique theory more than its strongly empirically equivalent rivals, and theory-choice is therefore radically underdetermined.’

A constructive empiricist agrees with all of these premises, and offers a theory in lieu of the scientific realist position that allowed for such radical underdetermination to begin with.

III. Its Discontents

Van Fraassen wishes to create a working, positive model of science without committing ontologically to things he or the rest of the epistemic community can’t directly sense (and even some things you can), including small organisms, atoms and their components, ‘public hallucinations,’ (van Fraassen 2001: 155) and cosmology. However, certain parts of his theory must be air-tight to overcome the standard position of scientific realism. In this section, I will try to show that he still has things to work out, to say the least.

A. Observability

To van Fraassen, our biology and physics determine what is observable. And when I say ‘our,’ I mean we humans, at this point in time. The reason it is limited to we humans is that we are, as far as we know, the only members of our epistemic community. There are many ways to refute this statement, and there are even ways accept it and still believe in (directly) unobservable entities, but let me begin by making this distinction much more moot than van Fraassen thinks it is.

Let us set up a thought experiment, where the epistemic community is unable to hear pitches higher than a certain tone, yet dogs is able to hear the tone just fine. A subject buys a dog whistle that works to create two tones: one that is observable by humans, and one that is too high a register to be observable. However, the mechanism which creates the tones is the same for the two notes, save the pitch. The subject then blows the whistle to several dogs hooked up to neural-network dog-brain analyzers which report that the part of the brain that becomes active to these dogs is the same part of the brain that becomes active when listening to human listenable whistles. According to constructive empiricism, this experiment and any theory that would be adequate in regards to the results of the experiment would not warrant us in believing there was any sounds whatsoever from the higher-than-observable pitches. To me, this thought experiment goes to show that the line between observable and not observable is not only vague (something he acknowledges) but also something that is meaningless.

Another fact that is of interest in the observable/unobservable debate: microorganisms. Many biological theories posit single-celled structures that are crucial to the existence of multi-cellular structures that are indeed observable. However, it seems that as soon as these tiny organisms pass a certain threshold determined by our personal biology, then they are deemed unobservable and we must not commit ontologically to their existence. However, then how would van Fraassen explain the fact that there are some single-celled structures which are visible to the naked eye? It seems as though even though because we are able to see some of ostrich eggs and xenophyophore (giant, single-celled organisms living at the bottom of the sea), it is generally accepted that we accept the type known as ‘single-celled organisms.’ If we are already ontologically committed to directly-observable single-celled organisms, then why not extend that ontological commitment to smaller single-celled organisms that just happen to be smaller than the naked human eye? This limits our observability to our biology and the physics of our anatomy. However, our biology also equipped us with a brain to create tools for observation, from telescopes to sonar equipment to microscopes. These tools allow us to observe things that would otherwise be out of our biological reach (albeit indirectly). Furthermore, indirect observation is still observation. This all leads me to conclude that we are warranted in passing judgments about the existence or not of at the very least microorganisms, if not much more than that.

‘If it is possible to distinguish between the observable and the non-observable, then it is possible to distinguish between empirical adequacy and truth,’ van Fraassen (2001: 166) writes. In my view, there is no way to distinguish between them in any objective sense of the word. There may be clear cases for us, now, but this does not mean that we are right. However, even if we give van Fraassen this point, that there is a way to distinguish between the observable and the non-observable, there is still a flaw. Indeed, James Ladyman in his (2000) argues that in order for constructive empiricism to work, van Fraassen must believe in objective modal standards of observability. Consider:

‘The circumstances in which we would observe the moons of Jupiter and dinosaurs never obtain—they are counterfactual. Hence, in order to demarcate the observable in a principled way that can bear the burden placed upon it in the epistemology of constructive empiricism, and… independently of what has…been observed, the constructive empiricist is committed to believing in at least some counterfactuals.’

Apparently, constructive empiricists must entertain counterfactual statements; that is to say, in order for constructive empiricists to talk about what is observable and actual, they must commit to more than what is observable and actual. This implies belief in objective modalities that are themselves not observable, thus undermining one of the main motivations for constructive empiricism in the first place.

However, even after all of this talk about observability, it is not clear that we have completely refuted what van Fraassen has to say about the ontological status of unobservables. Remember: he acknowledges that believing in unobservables (or at least the unobserved) may have pragmatic value, and that it is not irrational to do so. He maintains, however, that it is not necessary for the success of science. Remember: this assertion assumes that there are certain things which are unobservable in principle, that is, unobservable not because we, as humans at this point in time, are unable to observe them, but that they are not able to be observed by any one, ever, from now till the end of the epistemic community of the world we know of. Even this I will grudgingly allow, using a method van Fraassen would frown upon. Inductively, and coming from a realist perspective, there are so many things that were at some point unobservable that have now been discovered, that there are pretty high chances that there will always be something that will remain unobserved by our epistemic community, even when reaching its infinite limit, thus rendering it even indirectly unobservable. At this point I will bite the bullet, if you could call it that, and say that these proposed objects we can know nothing of. But until we reach the end of our epistemic community, there are still good reasons to not only accept theories as empirically adequate, but also believe in the proposed unobservables.

A further problem that might be mudding the waters is the meaning of the term ‘exist’. Presumably, what van Fraassen means when he says that scientific realists must “believe that [scientific theories are] true” is that they refer to objects that are real. I interpret van Fraassen as meaning by this that they do, in fact, physically exist. However, a scientific realist is not committed to that. The theory of relativity is not something that physically exists, however it is a theory that predicts, describes, explains, and defines many physical phenomena accurately. So, in a sense, they are undeniably real in the sense that it is, in fact, a certain set of parameters and formulas we do, in fact use, and take to be the greatest approximation to the truth when it comes to large enough objects, even though, according to Popper, Einstein himself said it was false (Popper 1974: 121)

The most decisive way that I could come up with to try to refute the claim that belief in unobservables is unnecessary for empirical adequacy is the fact that there are many occasions in science, especially in bio- and nanotechnology, that we humans manipulate ‘unobservable’ entities for observable results. When we, as a scientific community, create single molecules of insulin for mass production, or subject patients to gene therapy, or create carbon nanotubes only atoms wide to provide the maximum amount of strength in the lightest of weights, we are directly observing the consequences of the manipulation of unobservables. To not believe in the unobservables necessary for the creation of their manipulation’s observable consequences is completely irrational. Even using van Fraassen’s terminology, the only empirically adequate theory is that which posits the actual physical existence of the unobservables constructive empiricists have to deny. Therefore, there are times when the only acceptable (and in fact the necessary) position to take is that of the scientific realist.

B. Superempirical Virtues

There is another proponent of constructive empiricism which falls under intense scrutiny: the equation of empirical virtue with evidential and, thus, epistemic virtue. To put this simply, this is another formulation of his previous claim that the only way we can know of anything is to directly experience it, observe it. In this section I will argue that although some superempirical virtues such as aesthetic pleasantness or simplicity have no innate reasons to be epistemically advantageous, there are instances where other superempirical virtues, specifically explanation and coherence, do have epistemic virtue. It will follow, from the picture I wish to paint below, that these so-called ‘superempirical’ virtues are more than just pragmatic in nature.

It seems that the statement (S) that ‘The only type of valid epistemic evidence is empirical evidence’ would be heartily accepted by constructive empiricists (and possibly empiricists in general). However, to constructive empiricists, the only way (S) (an epistemic claim) would be accurate is if it itself has been empirically proven. This brings up two questions: (1) is (S) empirical and (2) if it is, has it been shown to be true? I do not know the answer to (1), but I believe it might not be. If one approaches knowledge from an empirical point of view, the only way to justify that statement is to argue that it is the best explanation from our observed experience, and constructive empiricists have just abducted as they wished not to. Also, I propose no to (2), because we have good reasons to believe that other types of evidence are also epistemic, even if we privilege empirical evidence (coherence with other empirically adequate theories, for instance).

1. Explanation and Abduction

As I mentioned before, constructive empiricists must deny that explanation has any epistemic virtue whatsoever. Accepting a theory’s explanations is a pragmatic virtue, as ‘…theory acceptance has a pragmatic dimension.’ Furthermore, the explanatory power of a theory ‘insofar as [it] goes beyond consistency, empirical adequacy, and empirical strength… do[es] not concern the relation between the theory and the world, but rather the use and the usefulness of the theory’ (van Fraassen 1980: 88). The interesting thing about van Fraassen’s position is that he does not deny that explanation has some value in the proves of selecting scientific theories, just that he claims that the explanation in-itself is no grounds for picking the theory, as explanation in itself will probably not bring about observable consequences and as such is not empirical. This point is immediately contestable.

The theory of evolution is generally accepted to have been an abductive inference. It explains a lot about the origins of species through the process of natural selection. And although there have been opportunities to show predictive power for the theory, there are no empirical tests that can fully mimic the process to such a point that we would be able to warrant, according to van Fraassen’s standards, empirical adequacy. Additionally, ‘evolution’ itself refers to an, again, according to van Fraassen, unobservable process. Nevertheless, it as accepted by the vast majority of members of the scientific community and even van Fraassen himself.

At the end of his chapter critiquing realism, van Fraassen provides a model of the changes in scientific theories over time not as having an ultimate goal (like Intelligent Design advocates might say of species), but instead as a Darwinian fight for survival where: ‘For any scientific theory is born into a life of fierce competition… only the successful theories survive—the ones which in fact latched on to actual regularizes in nature’ (van Fraassen 1980: 40). The irony, of course, is that, if my interpretation is correct, he is falling right into the trap he crafted for the scientific realist.

Van Fraassen’s inconsistencies aside, abduction seems to be a real way of thinking that is justified by its provisions of satisfactory explanations. Of course, just like induction, it is not infallible. Also, as Ladyman reminds us in his (2002: 219), neither abduction nor induction (nor deduction, for that matter) is safe from the skeptic, so, depending on your position, either abductions is as bad as induction or as good as induction (possibly deduction as well).

2. The Empirical Virtue of Coherence

There is yet another superempirical virtue that I find to have evidential virtue when applicable, and that is coherence. Here I will argue that even if one agrees with van Fraassen in that empirical adequacy is the strongest of epistemic virtues, coherence could still supplement the epistemic content of a theory. Coherence for its own sake does not necessarily mean it is an empirical virtue, as one could easily imagine a thesis cohering with another that does not have any empirical adequacy. I am going to frame this argument in the terms van Fraassen himself proposes, in order to show that even when giving him most of his points even when they may not be due, coherence is easily interpretable as epistemically valuable and thus his thesis that empirical adequacy is the only factor in determining epistemic value.

There may be instances when one is trying to determine the epistemic value of a theory, T₁. Let us suppose, of course, that this theory is empirically adequate for predicting phenomena, P, such that [T₁, P]. P just so happens to be related in an empirically significant way, R, to another phenomena, Q, such that [R (P, Q)]. Phenomena Q, in turn, has an empirically adequate theory, T₂ such that [T₂, Q]. Now, let us also suppose that there is a theory, T₃, such that it is also empirically adequate in describing phenomena P, such that [T₃, P] yet T₃ is inconsistent with T₁ and is furthermore incoherent with T₂. In my view, even though both T₁ and T₃ are empirically adequate in describing P, T₁ is not explicitly incoherent with T₂ and thus T₁ has added evidential support T₂ has with its empirical adequacy in describing Q. Thus the preference of T₁ over T₃ is not a purely pragmatic one, it is also supported by its coherence with another relevant theory that is empirically adequate. If my characterization holds, empirical evidence is not the only epistemic evidence, and thus empirical adequacy is not the only virtuous manner of obtaining evidence.

To put it more simply, if there are two empirically adequate theories vying for the same phenomena, it makes sense to pick the one that coheres with another theory which is also empirically adequate, especially if the two phenomena in question are related somehow. This gives evidence not only from the theory itself, but also from the other theory which has already been established to be empirically adequate.

IV. Concluding Thoughts

I don not know if this is really begging the question, but it seems to me that a scientific realist will always have an upper hand over the anti-realist about science from the brute fact that science works. Yes, I see a similarity between the preceding sentence and Putnam’s ‘No miracles’ argument. However, the point of this paper was to show that (1) in order for constructive empiricism to work, van Fraassen needs to convince us to drop whatever scientific theory we have (especially if we’re realists) and become constructive empiricists. However, all in all, even if we accept all of van Fraassen’s arguments, there are still problems with the position. There’s the problem of the apparent contradiction regarding objective modalities as I mentioned before. There’s also the problem of underdetermination. One of the main motivations for becoming an anti-realist about science was that if one accepts the Quine-Duheim thesis, there is a strong underdetermination to our theories about the world. This is because, for any theory, there’s an infinite number of theories that are also empirically adequate. However, constructive empiricism falls for the same objection: for every empirically adequate theory, there is also another infinite set of empirically adequate theories and thus theory-choice becomes impossible to be determined objectively. So much so, that in (Ladyman 2002: 212-3) there is talk of van Fraassen rejecting abduction yet ‘advocating a rule of “inference to the empirical adequacy of the best explanation.”’

Without a doubt some of his arguments could be interpreted as circular and there are some pretty big potential flaws, but van Fraassen’s constructive empiricism is the biggest threat to realism in the sciences since The Structure of Scientific Revolutions. It is a powerful force and interpretation that must be dealt with in order to have a successful philosophy of science.

At the end of the day, though, constructive empiricism did not provide an adequate enough philosophy of science. So, for me, personally, I will stick to scientific realism, unobservables and all… at least until something more convincing comes along.

References

Haack, S. (1998): ‘“We Pragmatists…”: Peirce and Rorty in Conversation’, Manifesto of a Passionate Moderate, Chicago: The University of Chicago Press.

Ladyman, J. (2000): ‘What’s Really Wrong with Constructive Empiricism? Van Fraassen and the Metaphysics of Modality’, The British Journal for the Philosophy of Science, 51.

Ladyman, J. (2002): Understanding Philosophy of Science, New York: Routledge.

Popper, K. (1974): “The Problem of Demarcation”, Popper Selections, Princeton: Princeton University Press.

van Fraassen, B. C. (1980): The Scientific Image, Oxford: Oxford University Press.

van Fraassen, B. C. (1989): Laws and Symmetry, Oxford: Oxford University Press.

van Fraassen, B. C. (2001): ‘Constructive Empiricism Now’, Philosophical Studies, 106.

This work is licensed under a
Creative Commons Attribution-No Derivative Works 3.0 United States License.

the so-called death of descriptivism

for a very long time--actually from about russell's "on denoting" paper published in the 1900's (decade, not century) till circa 1980--descriptivism ruled the theory of proper names. names did not actually denote anothing according to this view, but were shorthand versions of descriptions. names were descriptions, which in turn gave meaning to the term. so a proper name gave a unique description to the individual in question and that's what the individual was. the main motivation for this position was a fregean reaction against the millian view of proper names where a name just meant that thing you're talking about.

then of course the young prodigy savior of modal semantics saul kripke came along and revolutionized the entire field of philosophy of language. as mcginn noted in his review of the book in philosophical review, either you hated naming and necessity, you loved it, or you were genuinely confused. this new causal-historical view of names was completely different from the descriptivism that preceded it and there was a huge party for those who feared metaphysical committment and nominalists were happy and ockam had a party in his grave and all that good stuff and blah blah blah blah blah.

but was this celebration justified? was descriptivism really defeated like kripke thought?

as that young, star-crossed poet juliet once said, "what's in a name? a rose by any other name would smell as sweet!" this insight would play right into the conniving hands of kripke, who would make it seem that it shows how names are arbitrarily chosen to baptize a particular entity, whether an individual or a natural kind or whatever. but then i guess the nature of the question shifts as one attempts to pinpoint how names are actually acquired.

according to kripke, in the second lecture of the book, delivered in princeton i believe it was the 22nd of january, 1970, proper names for particular entities or kinds are introduced into a language one of either two ways. the first way is by fixing the reference by means of description. in other words i might say, "i need a name for the hairiest cuban-american raised in miami currently studying in scotland. i shall name him 'G'." see what i did there was that i came up with a definite description. instead of using that definite description every single time i want to refer to this particular individual, i pretty much just came up with a shortcut of sorts.

the other way one can introduce a name into a language is by using ostensive gestures, pretty much. so in other words you might go ahead and visit your local animal shelter and pick out a puppy from there. you take it home and you point at it and you say "i shall name this dog, 'D'." you could just say "D" as you point at it but then, of course as quine might point out, you might be naming the dog, sure, but you also might be naming the puppy slice or the undetatched puppy part or whatever the fuck that crazy quine might say. so even if you don't downright say "the dog's name is 'D'," in your mind you make the connection between the name and the type of thing you're actually naming. however, including this 'type' categorization or as kripke calls it the 'sortal' word as well, you ARE including a descriptive element to the ostensive definition as well.

going back to the famous shakespeare quotation once again, sure that rose could have any other name and smell sweet. but whenever somebody decided to call it a "rose" they said hey, look at that fucking flower over there, i'm gonna name it "rose." so, at the very least in the introduction of the term, the name of the plant was coupled with a recognition of what they were talking about and thus a description.

so basically what i'm trying to say here is that, even in kripke's view, descriptions are INDISPENSABLE, and are thus built in to EVERY noun term--whether it be proper or categorical-- and kripke pretty much fails in debunking good ol' earl of russell.

Hume & extreme empiricism

Hume's extreme skepticism about any empirical, observed knowledge of the external world is based on a very misguided and extreme empiricism. Although he allows for knowledge of certain simple mathematical and logical truths, anything beyond that is not directly supported by experience, and thus condemned unreasonable. To reconstruct his argument briefly: when interacting with the external world, we can be sure of our impressions of the sensations from the external input. However, we can never be certain about anything regarding these impressions other than that we experience them. Thus, making any sort of rational statement about these impressions goes beyond our experience. We are so uncertain about these impressions that we cannot be even sure that impressions we have received in times prior following a certain pattern will continue to do so. This is what some philosophers have called the Principle of the Uniformity of Nature (PUN). It is because of PUN that we believe something causes another thing. This principle is in fact an inferred hypothesis (induction) that has appeared to work in the past; but because we can’t truly experience this uniformity—only the perceived effects of it were it true—there is no rational way we can justify our own belief in its (PUN’s) existence. Moreover, because most, if not all observational (i.e. scientific) knowledge is based on this assumption, we have no more reason to believe in scientific knowledge than any other method of obtaining knowledge—methods a scientific person may consider to be complete hogwash (i.e. tarot, soothsaying, etc).

Obviously Hume goes wrong somewhere in this argument. Scientific knowledge does, more often than not, make accurate predictions about the future. They predict astrological phenomena all the time, for one. We also rely on technologies that have been enabled for use by scientific and engineering advances only producible by the application of scientific formulas that have at least at some point or another been tested with the rigor of experience. But finding these types of examples would not persuade anyone just yet, we must somehow prove the validity of the Principle of the Uniformity of Nature.

To be quite honest I’ve always been inclined to just toss aside skepticism of this nature because it seems so set against the intuitive outlook of the world that it can’t possibly be right. But let us give the skeptic a fighting chance. First, the Principle of the Uniformity of Nature is the assumption that underlies any notion of cause and effect. No principle of the uniformity of nature and no induction is possible. Inductions of all shapes and kinds would be impossible. If the clouds were really dark outside, the temperature dropped various degrees, and you heard a couple of thunderclaps, you would have no more reason to believe that there was going to be a nasty thunderstorm than if you were to believe that a sandstorm were to appear where you stood. Or that you were going to spontaneously combust. This is ludicrous!

We experience the PUN because we continue to see patterns emerging in significant ways in our everyday lives; we are actually more reasonable to believe in it than not. If you were to eat, among other things, tomato one day and you break out in hives, you realize that something you ate today might have brought those hives. After some self experimentation, or a visit to an allergist, you realize that eating tomatoes will be directly followed by those hives, and assuming you don’t like hives, you will discontinue your ingestion of tomatoes. Being a reasonable person, in my opinion, is at least in part recognizing that these patterns do emerge, identifying the relevant patterns in your life, and the acting accordingly. These patterns are experienced if only we expand on our notion from the Humean, mostly barren idea that we can only experience sense impressions, to a more broad conception of experience as the interaction between the senses and our own intellect to analyze it.

The main problem justifying this PUN philosophically is that it is an induction. Inductions are, by definition, logical inferences that will never be 100% certain. They are the proposal of a general rule or probability based on the experience of one thing following another significant amount of times. Inductions themselves are not deductively provable. Deductions are the other way around, there is a rule, and we are used to apply that rule in order to get the output. Deductions actually take less thought, because as long as you understand the rule, you can never misuse it. Inductions are a bit more synthetic, because it requires one to recognize patterns. But the induction itself, as a mechanism of pattern-recognition, is not itself applicable to any deduction, and it is thus deductively invalid. But this is okay! It doesn’t have to be!

The practice of creating and using inductions is valid because it works. Inductions have worked, do work, and there is no reason to believe that they will stop working any time soon. We have a great, vast amount of evidence that inductions have worked. Every time that we set foot in a car we are actually making an induction—that it will work just like the last time, that our seatbelt will actually work according to the standard safety regulations—and we are betting our lives on it. I guess this might be a pragmatic justification of induction and, by extension, the PUN.

This is what happens when empiricism is taken to the extreme. In the world of Hume, where no induction is rationally valid or justifiable, we are blind rats living in an ever evolving maze without any cheese. Sure, we can never be 100% sure of our inductions or any observational knowledge, we’d be bigger fools to think we have no rational reasons to believe them.

architecture of theories

from Charles Sanders Peirce. "The Architecture of Theories." The Monist January 1891. 161-76.

If a man, being seized with the conviction that paper was a good material to make things of, were to go to work to build a papier mache house, with roof of roofing paper, foundations of pasteboard, windows of paraffined paper, chimneys, bathtubs, locks, etc., all of different forms of paper, his experiment would probably afford valuable lessons to builders. But it would certainly make a detestable hosue. So are those one-idea'd philosophers whose work is exceedingly interesting and instructive, and yet are quite unsound.
The remaining systems of philosophy have been of the nature of reforms, sometimes amounting to radical revolutions, suggested by certain difficulties which have been found to beset systems previously in vogue; and such ought certainly to be in large part the motive of any new theory. This is like partially rebuilding a house. the faults that have been committed are, first, that the dilapidations have generally not been sufficiently thoroughgoing, and second, that not sufficient pains has been taken to bring the additions into deep harmony with the really sound parts of the old structure.
When a man is about to build a house, what a power of thinking he has to do, before he can safely break ground! with what pains he has to excogitate the precise wants that are to be supplied! what a study to ascertain the most available and suitable materials, to determine the mode of construction to which those materials are best adapted, and to answer a hundred such questions! Now, without riding the metaphor too far, i think we may safely say that the studies preliminary to the construction of a great theory should be at least as deliberate and thorough as those that are preliminary to the building of a dwelling-house.

What an insight. In order to create a philosophical system, we have to make sure that we're not only using sound architectural design, but we also need to use the right materials and survey the land for the best place. Great analogy