Cassius Circle: David Hume’s ‘Of Miracles’

[dastardly stem]

I certainly hate feeling like I'm pushing a whole new thread of discourse on this. It appears you and Physics Guy, Chap and Kishkumen have some momentum down a path I'm less equipped to play along with, even if I'm interested in the thread overall. Just noting, if I'm too much of a distraction, really, don't feel bad leaving me be off in the corner flailing my arms around talking to myself.

I’ve begun to hesitate on this ever since I became aware of Milman Parry and Albert Lord did their famous study on oral culture and modern bards like Avdo Međedović. The passage of time in oral culture doesn’t guarantee corruption of knowledge anymore than it guarantees preservation of it.

That's what makes it so tricky, in my estimation. There's no guarantee at all, either way. With extended passages of time as an added factor, it feels to me the "witness" represented by third hand accounts, hardly seem in any sense reliable. If added to that there are all sorts of reason to be suspicious of the witness accounts, soon we have witness that is nothing more than hearsay.

The authors of the New Testament may not have been eyewitnesses, but they could be transmitting authentic accounts. Not necessarily all of them, but perhaps some, or even just one of them.

What is an authentic account of something that likely did not happen? Transubstantiation is just a claimed miracle that is unfalsifiable. As such there's no basis to the claim it really happens. "it does turn into the body and blood, but it doesn't look like the body and blood, but since we think it turns into it, that's what it is." The Resurrection of Jesus is nothing more than that.

I take claims to be evidence in and of themselves.

I think this is tricky. The claim can be evidence in and of itself, if say, the claim is something like, "My dog had puppies yesterday". In this claim my comment can serve as evidence because it's very possibly true, and I am an actual witness to the results. I'm claiming to have seen the puppies. On say, the gospels, there is no witness claiming they saw Jesus spitting on a blind person's eyes to heal him. On say, transubstantiation, there is no witness. It's all an internal unfalsifiable dogmatic belief. I don't see how the claim is evidence of anything other than people believe it.

[Kishkumen]

What is going to make this even weirder is that Hume didn't think there nothing to "substance" beyond it being a collection of properties/attributes something has. The more traditional accounts see substance as being distinct and mutually exclusive to properties/attributes.

OK. Interesting. I feel lost already. I thought the chairness of a chair is substance, while the material it is made out of is accidental.

[Physics Guy]

I certainly don't mean to imply that any evidence for ancient miracles is on a par with scientific evidence, but I'm not always sure that we're clear about exactly what the difference is.

I believe physics stuff that I read in published journal articles. I don't believe everything I read, by any means, but I accept conclusions like the one from the particle physics community that Higgs bosons are real. Quite often I have no way of testing those conclusions for myself, however. Even to be sure I can fully follow their reasoning I would have to spend more time than I'm willing to invest in boning up on high-order perturbation theory in quantum field theory and on particle detector physics. And there is no way I'm ever going to be able to dig a CERN-sized tunnel in my own backyard to do an independent experiment.

I'm believing accounts from other people that I am not going to verify for myself. I hope it's not just because I find the Higgs boson a priori plausible whereas I'm biased against things like resurrections. If it were only that, then science would just be a matter of which memes are currently popular. We're supposed to try to do more than that.

I'm not expecting Hume to toss off a full philosophy of science as a side project, here. But I'm hoping that whatever he ends up saying about why one should or should not believe in miracles will be compatible with a reasonable scientific response to difficult observations. I'm expecting that to be possible; I'm not trying to defend miracles by saying they're just like science. I'm just hoping we don't end up with Hume settling for a facile dismissal of miracles that sounds nicely scientific and rational but that would actually hamstring physics if we had to apply it to our work.

[Physics Guy]

I may just simply be wrong about what "substance" is supposed to mean, but for what its worth my understanding is not that the substance of "chairness" is separate from all of a chair's features and properties. What I think is that chairness is a certain fuzzy set in the space of all properties and features. Some properties are necessary for all chairs, such that things without those properties cannot be called chairs: those properties are part of the substance of chair-ness. Other properties can optionally take a large range of values for a chair. Those are the accidents.

Consider a reduced world where the only possible properties of a thing are being round or square; being red or green; and being thick or thin. Every thing in this world must choose one of those options in each of those categories (so there are only eight kinds of thing in this world). Then I say that all round, red things are "blubs". Every blub, like every thing in this limited world, must be either thick or else thin; but thickness or thinness has no bearing on whether or not a thing is a blub. The substance of blub-ness is being both round and red. Thickness and thinness are accidental to blubs.

That is of course trivial in the world of eight possible things. In the real world, where we may not even know how many categories or options there are, the issue of substance versus accident is less obvious—not least because there may be decisively relevant properties that are not really properties of a thing in isolation, but concern its relationship to other things. The substance of "my dog", if that's really a possible substance, is not only about a dog but also about me.

My idea at least, though, is that this is really still the same issue as it was with the blubs, just with more possibilities.

[Chap]

I may just simply be wrong about what "substance" is supposed to mean, but for what its worth my understanding is not that the substance of "chairness" is separate from all of a chair's features and properties. What I think is that chairness is a certain fuzzy set in the space of all properties and features. Some properties are necessary for all chairs, such that things without those properties cannot be called chairs: those properties are part of the substance of chair-ness. Other properties can optionally take a large range of values for a chair. Those are the accidents.

Aquinas's use of the terms rendered in English as 'substance' and 'accident' takes place within a disciplined philosophical context that one learns how to work in by (in part) adopting an agreed technical vocabulary acquired when one is (or rather was) a student of philosophy in a medieval university. You can't get very far in understanding what he is saying by working out 'reasonable' meanings of the terms for yourself, any more than you can approach thermodynamics by working out your own meanings of (say) entropy and enthalpy as opposed to learning the technical meaning of those terms for specialists.

But you don't need to become a student of Thomist philosophy to get the point I was making when I posted that extract from the Summa.

[DrStakhanovite]

My initial comments on paragraphs 10-1 and 10-2 drew some insightful commentary by PhysicsGuy (see here and here) which compelled me to look deeper into some side issues. Turns out, the reading I had done on Anglican theology was actually written by someone who took a minority position regarding eucharistic theology. In addition to mistaking a minority position for majority consent, I was also unaware of the diversity of views within Anglicanism on how to interpret the Thirty-Nine Articles of Religion. To make the matter even more complex, upon consulting with a church historian, I discovered that there have been multiple shifts in the meanings of theological terms regarding the eucharist since the 17th century down to the 21st century. Given how far afield this takes me from the topic at hand, I don’t plan to say much more about it other than to marvel at just how fun it is to accidentally stumble back on to a topic you’ve only spent a cursory amount of time and find a whole new complex vista you never considered before!

There is one comment from PhysicsGuy that I would like to discuss more:

Anyway, if Hume's discussion of miracles is really going to begin from the idea that the Eucharist is supposed to be a frequently observed violation of the laws of nature, then he's really starting off on the wrong foot, because apart from misguided pious superstition the Eucharist has never been supposed to be that kind of physical miracle. It has always been a safely unfalsifiable metaphysical miracle.

I am going to stand by my assessment that Hume is engaging in a good strategy here, but to justify that assessment I thought it might be worthwhile to include a resource on the use of “substance” in philosophy. The Stanford Encyclopedia entry has two paragraphs that I think help frame the issue. The author of the article gives two different senses with the first being more generic and broad:

There could be said to be two rather different ways of characterising the philosophical concept of substance. The first is the more generic. The philosophical term ‘substance’ corresponds to the Greek ousia, which means ‘being’, transmitted via the Latin substantia, which means ‘something that stands under or grounds things’. According to the generic sense, therefore, the substances in a given philosophical system are those things that, according to the system, are the foundational or fundamental entities of reality. Thus, for an atomist, atoms are the substances, for they are the basic things from which everything is constructed. In David Hume’s system, impressions and ideas are the substances, for the same reason. In a slightly different way, Forms are Plato’s substances, for everything derives its existence from Forms. In this sense of ‘substance’ any realist philosophical system acknowledges the existence of substances. Probably the only theories which do not would be those forms of logical positivism or pragmatism that treat ontology as a matter of convention. According to such theories, there are no real facts about what is ontologically basic, and so nothing is objectively substance.

I would submit that this use of “substance” fits with current Roman Catholic teaching on transubstantiation. They don’t require believers to subscribe to a specific metaphysic, just that a fundamental alteration has happened to the host that changed its most basic nature. If a believer wants to understand that in terms of Thomism or Neo-Kantian metaphysics, it doesn't matter.

The second sense of the term is more narrowly construed and the details become dependent on the broader system/school of thought being utilized:

The second use of the concept is more specific. According to this, substances are a particular kind of basic entity, and some philosophical theories acknowledge them and others do not. On this use, Hume’s impressions and ideas are not substances, even though they are the building blocks of—what constitutes ‘being’ for—his world. According to this usage, it is a live issue whether the fundamental entities are substances or something else, such as events, or properties located at space-times. This conception of substance derives from the intuitive notion of individual thing or object, which contrast mainly with properties and events. The issue is how we are to understand the notion of an object, and whether, in the light of the correct understanding, it remains a basic notion, or one that must be characterised in more fundamental terms. Whether, for example, an object can be thought of as nothing more than a bundle of properties, or a series of events.

This sense of “substance” is captured by the Aristotelian categories (eventually Thomistic ones) that have dominated Roman Catholic thought since the close of antiquity to the modern period.

Now I think it only proper to at least give Hume some space to declare his position in regards to “substance” and to that end I’ll quote from his ‘Treatise’: Section VI, 6-2:

The idea of a substance as well as that of a mode, is nothing but a collection of simple ideas, that are united by the imagination, and have a particular name assigned them, by which we are able to recal, either to ourselves or others, that collection. But the difference betwixt these ideas consists in this, that the particular qualities, which form a substance, are commonly refer'd to an unknown something, in which they are supposed to inhere; or granting this fiction should not take place, are at least supposed to be closely and inseparably connected by the relations of contiguity and causation. The effect of this is, that whatever new simple quality we discover to have the same connexion with the rest, we immediately comprehend it among them, even though' it did not enter into the first conception of the substance. Thus our idea of gold may at first be a yellow colour, weight, malleableness, fusibility; but upon the discovery of its dissolubility in aqua regia, we join that to the other qualities, and suppose it to belong to the substance as much as if its idea had from the beginning made a part of the compound one. The principle of union being regarded as the chief part of the complex idea, gives entrance to whatever quality afterwards occurs, and is equally comprehended by it, as are the others, which first presented themselves.

Now I want to be clear here that I really appreciate PhysicsGuy’s comments, but I don’t want to make him play the role of defending religious beliefs and doctrines he doesn’t actually hold. Offering a different perspective and giving needed corrections shouldn’t come with that kind of social burden. So I’m going to draw inspiration from PhysicsGuy’s posts and create a hypothetical person who disputes my assessment of Hume’s strategy. Because I lack imagination, let us call him ChemistryCarl.

I can’t get behind calling Hume’s strategy as being “clever” at all. I think he conflates transubstantiation with real presence in the host and it leaves a bad taste in my mouth. More importantly is that transubstantiation isn’t considered a miracle and by beginning this section with that topic seems more foolish than clever.

I am forced to concede to Carl’s first point. I’m not fully convinced of it myself, but to meaningfully respond to it would require me to go much deeper into the writings of 18th century Christian theology to fully sort out and if it is one thing I’ve learned from watching Mormon Apologists is, dying for every hill is just stupid. So let’s chalk that up to a mistake on Hume’s part.

The second point I think misses the thrust of Hume’s strategy. I’m pretty comfortable with allowing a believer to say, “We have particular ways of understanding what miracles are and have finely graded distinctions concerning them, transubstantiation doesn’t meet the criteria for a miracle.” That’s cool and I can respect that, though I want to point out that the spirit of Hume’s comments thus far doesn’t actually need transubstantiation to be called a miracle to work.

Think a moment about what transubstantiation is all about. It is part of this ritual where a priest says a formulaic prayer over common bread and wine which God responds to by altering the fundamental reality of the bread and wine to match that of the flesh and blood of Jesus Christ. Now we may not classify that as a miracle on technical grounds, but it is still an event where God directly interacts with bread and wine, to change them in a way they wouldn’t normally change if left on their own.

Hume advises us that a “wise man, therefore, proportions his belief to the evidence”. Adopting Hume’s point of view here, what evidence do we have? Well we have no evidence from our senses because the change that takes place in the bread and wine happens on a level that we can’t perceive, even through instrumentation. All that we have left then is that evidence of testimony supplied by scripture and tradition, but Protestants vociferously contest that and in such a manner that it doesn’t look as if the Roman interpretation could be considered overwhelmingly better.

What sort of options does ChemistryCarl have in terms of responding to Hume? Empirically confirming transubstantiation is off the table and all sides seem to agree on that. ChemistryCarl could decide that the historical argument for transubstantiation is damn near watertight and proceed along those lines. There is also a third option where ChemistryCarl, which disputes Hume’s broader philosophy and argues that Hume is creating a false dilemma by not allowing for a rational argumentation from a non-empirical metaphysic.

I think that third option is what Hume wants, to quote the closing paragraph of the ‘Enquiry’:

When we run over libraries, persuaded of these principles, what havoc must we make? If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: For it can contain nothing but sophistry and illusion.

(Illustration of David Hume by Cassio Loredano)

[DrStakhanovite]

Paragraphs 10-5 & 10-6

To apply these principles to a particular instance; we may observe, that there is no species of reasoning more common, more useful, and even necessary to human life, than that which is derived from the testimony of men, and the reports of eye-witnesses and spectators. This species of reasoning, perhaps, one may deny to be founded on the relation of cause and effect. I shall not dispute about a word. It will be sufficient to observe, that our assurance in any argument of this kind is derived from no other principle than our observation of the veracity of human testimony, and of the usual conformity of facts to the reports of witnesses. It being a general maxim, that no objects have any discoverable connexion together, and that all the inferences, which we can draw from one to another, are founded merely on our experience of their constant and regular conjunction; it is evident, that we ought not to make an exception to this maxim in favour of human testimony, whose connexion with any event seems, in itself, as little necessary as any other. Were not the memory tenacious to a certain degree; had not men commonly an inclination to truth and a principle of probity; were they not sensible to shame, when detected in a falsehood: Were not these, I say, discovered by experience to be qualities, inherent in human nature, we should never repose the least confidence in human testimony. A man delirious, or noted for falsehood and villany, has no manner of authority with us.

And as the evidence, derived from witnesses and human testimony, is founded on past experience, so it varies with the experience, and is regarded either as a proof or a probability, according as the conjunction between any particular kind of report and any kind of object has been found to be constant or variable. There are a number of circumstances to be taken into consideration in all judgments of this kind; and the ultimate standard, by which we determine all disputes, that may arise concerning them, is always derived from experience and observation. Where this experience is not entirely uniform on any side, it is attended with an unavoidable contrariety in our judgments, and with the same opposition and mutual destruction of argument as in every other kind of evidence. We frequently hesitate concerning the reports of others. We balance the opposite circumstances, which cause any doubt or uncertainty; and when we discover a superiority on any side, we incline to it; but still with a diminution of assurance, in proportion to the force of its antagonist.

One of the background reasons for why I’m doing this thread is that I’m doing some private research on the history of philosophical analysis on causality. Hume is a very large influence on that topic, especially in the English speaking world of modern philosophy and as such I’ve been tussling with him on that front for some weeks now. I feel that causation is about as primitive as a concept can get in human reasoning and fundamental to our experience of reality, but Hume absolutely denies this and insists that humans don’t really experience causation. On Hume’s account, causation is merely this useful fiction humans have devised to link two different experiences together. Let me give an example, because this helps explain what Hume is saying about testimony.

Here is one of my favorite moments in baseball, where Nolan Ryan hits Robin Ventura with a pitch and Robin charges the mound and the benches clear. In a Humean analysis, everything you just saw is a series of experiences that you arrange internally and then make a narrative out of. Most of us watching this event see the ball hit Ventura, we imagine the pain this caused, and we intuit the motivation for why Robin charges Nolan; yet all of that is just a story we overlaid on the experiences to better comprehend it. Hume would say no one actually saw any kind of connection between Nolan throwing the ball, the ball hitting Robin, and Robin rushing Nolan.

Now the Nolan Ryan and Robin Ventura story is complex, it involves humans engaged in a culturally conditioned activity with loads of variables in play, does Hume still think this way if the example was a stripped down version of objects obeying physics? The answer is yes, Hume would make the same commentary about a cue ball knocking an eight ball into a corner pocket. You experience the cue hitting a white ball which travels across a surface and strikes a black ball, which then travels across a surface and into a pocket. A description of the event about a transfer of energy causing bodies to move according to physics is as much a story we tell ourselves as Robin angrily charging Nolan (according to Hume).

So what does Hume think causality really is? Humans identifying when two events are contiguous with regularity. Introducing a dry piece of paper to an open flame always happens before the combustion of paper, this happens with regularity when experiments are conducted and so, Humans conclude, that paper is flammable. The more regularity there is, the more confidence there is in predicting events and the less regularity, the less confidence there is. That is how a wise man proportions his beliefs to the evidence.

Now my explanation above is a very stripped down version of Hume’s thought, but I think it is sufficient to help flesh out what it is he is saying about witness testimony:

It being a general maxim, that no objects have any discoverable connexion together, and that all the inferences, which we can draw from one to another, are founded merely on our experience of their constant and regular conjunction; it is evident, that we ought not to make an exception to this maxim in favour of human testimony, whose connexion with any event seems, in itself, as little necessary as any other.

When apologists speak about the Book of Mormon witnesses, they’ll often put a certain amount of stress on the narrative of the lives of the witnesses post miracle. They’ll highlight a witness's unwavering testimony despite plenty of motivating factors to abandon it, so that they can then claim this adds a certain sheen of validity to the miracle account. Who would suffer persecution for a lie?

I think Hume would respond with something like, “Hey that is a great story, but great stories shouldn’t play a factor in trying to assess the truth of a miracle having occurred. What really matters here is the content of the witness's testimony and how well that content squares with what we know from our experience.”

Now that seems like an interesting way to take the wind out of an apologist’s sails, but is it a good way to assess the plausibility of an event in the past?

[Philo Sofee]

Fantastic thread guys! I can't help but wonder how Hume would have reacted to me kicking him seriously, and I mean seriously hard enough to break his leg if I kicked him in the shin? It could not and would not have happened had I chosen simply NOT to kick him. The cause of his leg breaking and the sheer pain, just has to be my kicking him as 3 witnesses saw and so testified as he sued me... I mean, surely he simply could NOT have said his leg just broke of its own accord and the pain overwhelmed him.... could he? Would he even be considered sane if he did so? And if he said his legs break and pain was not caused by my deliberate choice and movement of kicking him, I wonder what he would have thought if I kicked and broke his other shin as well?!

It is a fascinating topic...

I can't grasp the lack of causation. If causation isn't real, two events connected, then how on earth did Hume EVER communicate with anyone verbally?

[DrStakhanovite]

I certainly hate feeling like I'm pushing a whole new thread of discourse on this. It appears you and Physics Guy, Chap and Kishkumen have some momentum down a path I'm less equipped to play along with, even if I'm interested in the thread overall. Just noting, if I'm too much of a distraction, really, don't feel bad leaving me be off in the corner flailing my arms around talking to myself.

Sorry for the delay, I had to ration my time carefully for a bit. Your contributions are not a distraction at all, but rather welcome. Your comments all revolve around a similar set of points, so I’m going to quote just a part of your post, but I think I’ll be able to engage the substance of everything you said.

That's what makes it so tricky, in my estimation. There's no guarantee at all, either way. With extended passages of time as an added factor, it feels to me the "witness" represented by third hand accounts, hardly seem in any sense reliable. If added to that there are all sorts of reason to be suspicious of the witness accounts, soon we have witness that is nothing more than hearsay.

Tricky is a good descriptor, but when it comes down to it (especially with the discipline of history), all we really have is witness accounts. In fact, witness accounts make up for a large part of how information is passed along in our day to day life and even Hume thinks that when Humans provide testimony that a good deal of it is reliable:

Were not the memory tenacious to a certain degree; had not men commonly an inclination to truth and a principle of probity; were they not sensible to shame, when detected in a falsehood: Were not these, I say, discovered by experience to be qualities, inherent in human nature, we should never repose the least confidence in human testimony. A man delirious, or noted for falsehood and villany, has no manner of authority with us.

Testimony is really one of those things that doesn’t really lend itself to either being wholly true or wholly false. When testimony is being disputed factually, it is almost always directed at particular elements of a testimony and not the entire thing.

I mean consider the case of Heinrich Schliemann and Frank Calvert who used the texts attributed to Homer to discover the ancient remains of Troy at Hisarlik in modern day Turkey. Here is an ancient testimony that was composed and preserved in an oral culture for hundreds of years before a form of it was put to writing and preserved, then over two thousand years later two amateur archeologists can use this epic poem as a road map to the remains of an ancient civilization that had largely been lost to the annals of history. All in a story about gods and armies laying siege to a city that almost no one took as a literal account of real events.

If we adopt Hume’s views articulated thus far, it seems compatible:

There are a number of circumstances to be taken into consideration in all judgments of this kind; and the ultimate standard, by which we determine all disputes, that may arise concerning them, is always derived from experience and observation. Where this experience is not entirely uniform on any side, it is attended with an unavoidable contrariety in our judgments, and with the same opposition and mutual destruction of argument as in every other kind of evidence.

And this seems to be how we judge testimony nowadays anyhow. Testimonies that go against what we think to be true are immediately challenged.

[DrStakhanovite]

Thanks for the supportive comments Philo!

I can't grasp the lack of causation. If causation isn't real, two events connected, then how on earth did Hume EVER communicate with anyone verbally?

Short Answer: There is a shift in meaning that is context dependent and historically conditioned. Hume would never have a problem saying in court you caused his injury because the context of English jurisprudence is very different from that of the ‘Enquiry’. He is also assuming a notion of cause that was made popular by philosophers that has long since fallen out of use today.

Long Answer: To start with, up until René Descartes (1596-1650), Spinoza (1632-1677), and Leibniz (1646-1716), the idea of “cause” was understood to be any kind of valid explanation. Why this was so brings us back to the usual suspects in philosophy, the dreaded Greeks. Greek philosophy was very much concerned with how and why things undergo change. Aristotle’s so-called “doctrine of 4 causes” found in texts like the ‘Physics’ and ‘Metaphysics’ is probably the most influential instance of this. I’ll try and give a brief example of these four causes using the hypothetical situation of Hume’s damaged leg.

Material Cause: The physical materials that make up human anatomy (blood, fat, bone, sinews,etc).
Formal Cause: The shape and dimensions of human legs.
Efficient Cause: A backyard rogue named Philo Sofee delivering a swift kick.
Final Cause: The purpose behind breaking Hume’s leg.

Now if a judge asked you “Why did you kick Mr.Hume?” and you replied with “Because my brain sent electrical signals to my leg” the judge wouldn’t be very amused, even though what you replied with is factual; the judge was seeking a final cause and you gave him an efficient cause.

When scholasticism’s influence was petering out and Aristotelian physics was being replaced by Newtonian mechanics, the notion of “cause” was narrowed down to a mechanical understanding of “Efficient Cause”. Just as polemical aside, but the demise of the Aristotelian science within the university had more to do with Renaissance era magicians and their occultic practices than anyone who published during the Enlightenment period.

Actually, the whole notion that a large swath of 17th and 18th century advancements being called an enlightenment comes from the German philosopher Imannuel Kant, who dubbed it so. He also divided philosophers from this period into two broad camps; Rationalists and Empiricists. Now the previously mentioned Descartes, Spinoza, and Leibniz are considered the major hitters from the Rationalist bench and they looked at cause and effect as having a component of necessity to it. We have a cause (Philo kicking Hume) and an effect (Hume’s injured leg) and what bridges these two things is causal explanation which purportedly explains why Hume’s leg had to be injured. Why was it framed this way? Counterfactual reasoning played a big role, if Hume’s leg had remained unkicked, it would be undamaged. Thus Hume’s leg being damaged must occur when Philo kicks it.

Why did the Rationalists see a connection of necessity bridging Hume’s injured leg and Philo’s kicking? I think it was because they were system builders enchanted with the idea of something like a clockwork universe. The dream was building up a science of cause and effect that could be understood through a succession of axioms like geometry, a pristine and parsimonious categorization that could reduce all that is observed in nature by humans into concise laws of cause and effect.

Empiricists like Hume disputed this (going back to 10-3, bolding mine):

All effects follow not with like certainty from their supposed causes. Some events are found, in all countries and all ages, to have been constantly conjoined together: Others are found to have been more variable, and sometimes to disappoint our expectations; so that, in our reasonings concerning matter of fact, there are all imaginable degrees of assurance, from the highest certainty to the lowest species of moral evidence.

According to Hume, you could set up a 100 experiments with multiple people observing each experiment and no one is going to see any kind of necessary causal connection. All they will have are these experiences involving an uninjured leg being kicked and then an injured leg after the kick.

The kind of people Hume was taking aim at were working in natural philosophy (their word for what we consider the natural sciences today) like the Rationalists who were constructing laws of nature with regards to causation, “If you have an X type of cause it will always produce an X type of effect”. This is where we get the problem of induction; how many experiments do we need to do before we say something is a law of nature? Where do we draw the line and how can we justify where that line is drawn?

Hume would say any line would be drawn indiscriminately and such practices should be abandoned. All we can do is basically state how much confidence we have that one instance (Philo kicking Hume) will be followed by another instance (Hume being injured). Other Empiricists expanded on Hume’s suggestion and decided probability is the best way to gauge that confidence and the doctrine of probabilism was born.

Hume won a lot of 20th century philosophers over to his side. Bertrand Russell himself says that at best causation is a pre-scientific idea and at worst an anti-scientific one and modern causal statements are really nothing more than discussing the covariance of phenomena. Karl Popper was so convinced by Hume that he thought the problem of induction to be insoluble and published a deductive argument expressed formally in symbolic logic within the pages of the journal of ‘Nature’ that sought to prove probablism could never solve induction.