Hume on Causes

The great British empiricist philosopher David Hume (1711-1776) wrote that “There are no ideas which occur in metaphysics more obscure and uncertain than those of ‘power’, ‘force’, ‘energy’, or ‘necessary connection'” (An Inquiry Concerning Human Understanding, Library of Liberal Arts ed., p. 73).

Hume is most famous for his critique of naive or dogmatic assumptions about causality. “[T]here is not, in any particular instance of cause and effect, anything which can suggest the idea of power and necessary connection” (p. 75). To me, it seems to be the idea of an underlying power or force responsible for causality that he is mainly questioning. He has no doubt that we continually experience instances of cause and effect.

“[There is] no such thing as chance in the world” (p. 69). “[T]he conjunction between motives and voluntary actions is as regular and uniform as that between the cause and effect in any part of nature” (p. 98). Clearly, then, he did believe in the reality of cause and effect, but only wanted to reject naive claims about our knowledge of the world that purport to link experienced instances of cause and effect to explanations in terms of the operation of underlying powers. What we actually experience in these cases is just lawful regularity.

“It is certain that the easy and obvious philosophy will always, with the generality of mankind, have the preference above the accurate and abstruse…. The fame of Cicero flourishes at present, but that of Aristotle is utterly decayed” (pp. 16-17). But on the other hand, “All polite letters are nothing but pictures of human life in various attitudes and situations…. An artist must be better qualified to succeed in this undertaking who, besides a delicate taste and a quick apprehension, possesses an accurate knowledge of the internal fabric, the operations of the understanding, the workings of the passions…. However painful soever this inward search or inquiry may appear, it becomes in some manner requisite to those who would describe with success the obvious and outward appearances of life and manners…. Accuracy is, in every case, advantageous to beauty, and just reasoning to delicate sentiment. In vain would we exalt the one by depreciating the other” (p. 19). Clearly, then, Hume’s polemic against scholastic modes of reasoning does not at all mean he simply rejects the values of “accurate and abstruse” philosophy.

Neoplatonizing tendencies in the Aristotelian commentary tradition led to the common Latin scholastic view of causes as metaphysical powers operating behind the scenes that Hume is mainly concerned to criticize. Aristotle himself identified causes more broadly and much less speculatively with every kind of “reasons why” things are as they are and behave as they do. He did so without making extravagant claims to certain knowledge. Whereas scholastic philosophers characteristically debated the pros and cons of accepting various abstract propositions, Aristotle himself was fundamentally concerned with the use of reason to help interpret concrete human experience (see Aristotelian Causes).

Hume is a great philosopher, and so far I have focused on a positive appropriation of his work, having some points in common with themes I have been pursuing about causality and the notion of power. Robert Brandom’s innovative reading of Kant’s response to Hume points out that there are distinct limits to Hume’s approach.

“Kant read Hume’s practical and theoretical philosophies as raising variants of a single question. On the side of practical reasoning, Hume asks what our warrant is for moving from descriptions of how things are to prescriptions of how they ought to be. How can we rationally justify the move from ‘is’ to ‘ought’? On the side of theoretical reasoning, Hume asks what our warrant is for moving from descriptions of what in fact happens to characterizations of what must happen and what could not happen…. Hume’s predicament is that he finds that even his best understanding of facts doesn’t yield an understanding of either of the two sorts of rules governing and relating those facts, underwriting assessments of which of the things that actually happen (all he thought we can directly experience) ought to happen (are normatively necessary) or must happen (are naturally necessary).”

“Kant’s response to the proposed predicament is that we cannot be in the situation that Hume envisages: understanding matter-of-factual empirical claims perfectly well, but having no idea what is meant by modal or normative ones” (Brandom, Reason in Philosophy, p. 54).

Brandom continues, “To judge, claim, or believe that the cat is on the mat, one must have at least a minimal practical ability to sort material inferences in which that content is involved (as premise or conclusion) into good ones and bad ones, and to discriminate what is from what is not materially incompatible with it. Part of doing that is associating with those inferences ranges of counterfactual robustness…. So, for example, one must have such dispositions as to treat the cat’s being on the mat as compatible with a nearby tree being somewhat nearer, or the temperature a few degrees higher, but not with the sun being as close as the tree or the temperature being thousands of degrees higher. One must know such things as that the cat might chase a mouse or flee from a dog, but that the mat can do neither, and that the mat would remain essentially as it is if one jumped up and down on it or beat it with a stick, while the cat would not. It is not that there is any one of the counterfactual inferences I have mentioned that is necessary for understanding what it is for the cat to be on the mat. But if one makes no distinctions of this sort — treats the possibility of the cat’s jumping off the mat or yawning as on a par with is sprouting wings and starting to fly, or suddenly becoming microscopically small; does not at all distinguish between what can and cannot happen to the cat and what can and cannot happen to the mat — then one does not count as understanding the claim well enough to endorse it” (pp. 54-55).

Brandom concludes, “If that is right, then in being able to employ concepts such as cat and mat in ordinary empirical descriptive claims one already knows how to do everything one needs to know how to do in order to deploy concepts such as possible and necessary — albeit fallibly and imperfectly” (p. 55).

I am actually a little more sympathetic to Hume, in that I don’t read him as categorically rejecting the validity of concepts of necessity, only any possibility of certain knowledge of how they apply to the real world. I personally like the position of Leibnitz that necessity is real but always hypothetical, never categorical. But Brandom is right that Hume does not go on to emphasize how essential our fallible understanding of necessity is to our understanding of ordinary experience.

Nietzsche, Ethics, Historiography

Nietzsche famously criticized received notions of good and evil, and pointed out the inglorious role of “reactive” and resentful thinking about morals. To negatively frame our notions of goodness and virtue in terms of emotional reactions to bad things done by others is not an auspicious beginning for ethics. It results in a bad order of explanation that puts negative judgments of others before positive consideration of what is right.

Nietzsche pointed out that this occurs more often than we might think. A recurring emphasis on negative, blaming attitudes toward other people over affirmative values is unfortunately all too common not only in ordinary life and actually existing religious practice, but across what passes for the political spectrum. We ought to distance ourselves from this, and develop our values in positive rather than negative terms. We should aim to be good by what we do, not by contrasting ourselves with those other people. As an antidote to resentment, Nietzsche recommended we cultivate forgetfulness of wrongs done by others. I would add that we can have strong concern for justice without focusing on blame or revenge.

Like Aristotle, but without ever mentioning the connection, Nietzsche emphasized a certain sort of character development, and effectively advocated something close to Aristotle’s notion of magnanimity, or “great-souledness” as contrasted with small-mindedness. But in common with some modern interpretations of “virtue ethics”, Nietzsche tended to make whatever a presumably great-souled person might in fact do into a criterion, and consequently downplayed the role of the rational deliberation jointly emphasized by Aristotle and Kant.

Unfortunately, Nietzsche seems to have been so outraged by what he saw as widespread hypocrisy that he sometimes failed to take his own advice to avoid dwelling on the negative. This comes out in his tendency to make sweeping historical generalizations. Thus, he presented all religion in a negative light, and even went so far as to blame the “moralism” of Socrates and Plato for many later historical ills, while failing to note his own partial convergence with Aristotle.

Even at the peak of my youthful enthusiasm for Nietzsche, this negative judgment of Socrates and Plato always seemed wrong to me. Textual evidence just does not support the attribution of primarily “resentful” attitudes to either of them. On the contrary, Socrates and Plato began a completely unprecedented attempt to understand what is good in positive terms, and took great care to avoid prejudice in the process.

Partly as a consequence of his sweeping rejection of Socrates and Plato, Nietzsche looked for alternate heroes among the pre-Socratics, especially favoring Heraclitus. (In the 20th century, with different motivations, Heidegger expanded on Nietzsche’s valorization of the pre-Socratics over Plato and Aristotle, claiming that Heraclitus and Parmenides “had Being in sight” in ways that Plato and Aristotle did not. This seems to me like nonsense. As distinct from poetry and other artistic endeavors (which I value highly, but in a different way), philosophy is not about primordial vision or its recovery; it is about rational understanding and development toward an end, starting from wherever we actually find ourselves. While the pre-Socratics are important in a sort of prehistory of philosophy, the level of rational development they achieved was minimal. Extended rational development first bloomed with Plato, and then was taken to a yet higher level by Aristotle.)

Nietzsche also denied the reality or effective relevance of anything like Aristotelian potentiality, claiming that only what is actual is real. The semantic or expressive category of potentiality underwrites logical and linguistic modality, which among other things in turn underwrites the possibility of expressing objective judgments of “should”, as well as of causality, of which Nietzsche seems to have taken a Humean view. The general role of potentiality and modality is independent of all issues of the correctness or possibly prejudiced character of particular judgments.

Nietzsche’s denial of potentiality is thus related to a denial of any objective good and evil. It is akin to other views that attempt to explain values by facts. He thought mostly in terms of actually occurring valuations, and did distinguish better from worse ones, but mainly in terms of a kind of ad hominem argument from great-souledness or small-mindedness.

In my view, he should have been content to point out that many particular judgments are prejudiced or incorrect, and at any moment we have no sure way of knowing we accurately recognize which these are. Objectivity in ethics cannot be assumed as a starting point, but that does not mean there can never be any. Where it occurs, it is a relative status that is the product of a development. (See also Genealogy.)

Nietzsche’s poetic notion of the Eternal Return does in a way partly make up for his overly strong denial of any objective good or evil. The Eternal Return works especially as an ethical, selective thought that distinguishes purely affirmative valuations from others. I used to want to think this was enough to recover something objective that acts like a notion of good as affirmativeness, but that is contrary to what he says explicitly.

Modality and Variation

David Corfield suggests that modality has to do with ranges of variation. This seems extremely helpful. He connects Brandom’s notion of ranges of counterfactual robustness with mathematical analyses of variation. Corfield approvingly cites Brandom’s argument that in order to successfully apply empirical concepts at all, we must already be able to apply modal concepts like possibility and necessity. This always seemed right to me, but the talk about possible worlds made me worry about what sounded like impossibly strong quantification over infinities of infinities. Corfield also points out that Saul Kripke originally cautioned against uncareful extension of his possible-worlds talk.

It now seems to me that Brandom’s counterfactual robustness and Corfield’s mathematically analyzable variation together can be taken as an explanation for modal notions of necessity that previously seemed to be simply posited, or pulled out of the blue. Modality suddenly looks like a direct consequence of the structure of ranges of variation. Previously, I associated both structure and Brandom’s modally robust counterfactuals with Aristotelian potentiality, so this fits well.

Corfield also relates this to work done by the important 20th century neo-Kantian, Ernst Cassirer, on invariants behind the various systems of Euclidean and non-Euclidean geometry. He points out that Cassirer thought similar concerns of variation and invariance implicitly arise in ordinary visual perception, and connects this with Brandom’s thesis that modality is already there in our everyday application of empirical concepts.

The British Empiricist David Hume famously criticized common-sense assumptions about causality and necessity, preferring to substitute talk about our psychological tendencies to associate things that we have experienced together. Hume pointed out that from particular facts, no knowledge of causality or necessity can ever be derived. This is true; no knowledge of necessity could arise from acquaintance with particular facts. But if necessity and other modalities are structural, as Corfield suggests, they do not need to be inferred from particular facts, or to be arbitrarily posited.

The kind of necessity associated with structural determination is quite different from unconditional predestination. I want to affirm the first, and deny the second. Structural determination only applies within well-defined contexts, so it is bounded. If we step outside of the context where it applies, it no longer has force. (See also New Approaches to Modality; Free Will and Determinism.)

Leibniz is more familiar to me than Kripke, so when I hear “possible worlds”, I have tended to imagine complete alternate universes à la Leibniz. “Worlds”, however, could be read much more modestly as just referring to Corfield’s ranges of variation.

Aristotelian Causes

I’ve explained each of the four classic Aristotelian “causes” as playing what Brandom would call an expressive role, helping to explain other meaning, and pointed out how different this is from standard modern notions of what I’ve been calling univocal causality. An Aristotelian cause (aitia) is much more like a nonexclusive reason than it is like anything expressed by mechanical metaphors.

There is another very important modern way of thinking about these matters, inspired by Hume’s critique of realism about causes in the modern sense. Hume pointed out that modern-style talk about cause and effect involves a kind of inferential extrapolation from observed regular patterns of succession. Implicitly influenced by this, much work in the sciences relies directly on statistical correlations observed in data from controlled experiments. What particular causes are said to be at work then becomes a matter of optional statistical inference, subject to possible debate.

Then, too, from the side of subject matter, in fields concerned with complex dynamical systems that can only be modeled in a very tentative way — like ecology, economics, and medicine — it has come to be widely recognized that many causes combine to produce the results we see.

Both the statistical approach and what I’m gesturing at as a “complex systems” approach to causality avoid reliance on mechanical metaphors. Neither of these perspectives rules out underdetermination or overdetermination, or the simultaneous presence of both.

Aristotelian “causality” is simultaneously underdetermining and overdetermining. That is to say, in advance it leaves room for varying outcomes, but in hindsight it provides multiple rationales for a given outcome. Its purpose is to provide not certain prediction, but intelligibility and reasonableness.

In principle, nothing would stop us from combining this with statistical or complex-systems views, but these are still very different approaches. The statistical approach is quantitative and relies on counting minimally interpreted facts, where the Aristotelian approach is qualitative and puts the whole emphasis on rational interpretation. The complex-systems view relativizes causes in the modern event-based sense, without making them like any of the Aristotelian ones, none of which corresponds to an event. It is also not interpretive in the sense developed here.

One might consider mathematical-physical law as a kind of formal cause. Statistics and things like dynamic models could be taken as modern, quantitatively oriented descriptions of what I have called material tendencies. (See also Secondary Causes; Form; Aristotelian Matter; Efficient Cause; Ends; Natural Ends; Aristotelian Identity; Aristotelian Demonstration.)

Aristotle, Empiricist?

In contrast with Plato, Aristotle made major contributions to early natural science, and was concerned mainly to interpret human experience of the world. I previously noted with some sympathy John Herman Randall Jr.’s argument that Italian Renaissance Aristotelianism played a much greater role in the development of early modern science than is commonly recognized. I cannot, however, follow Leibniz and Kant’s superficial association of British Empiricist philosophy with Aristotle.

Locke, Berkeley, and Hume were all much closer to Descartes than to Aristotle on key questions related to subjectivity. For all of them, immediate presence to the mind played a foundational role. (See also Empiricism; Aristotelian Subjectivity; Mind Without Mentalism.)

(Locke, Berkeley, and Hume all argued with rather more subtlety and sophistication than Descartes. Unlike Descartes, Locke and Hume did not treat the human soul as a substance, and all three of the great British Empiricists produced detailed accounts of aspects of human cognition that are of lasting value, potentially somewhat independent of the mentalist framework in which they were originally developed.)

Locke and Hume did extensively and systematically develop the notion — commonly attributed to Aristotle in the middle ages — that everything in intellect originates in sense perception. As far as Aristotle is concerned, this seems an overstatement.

Aristotle characteristically looked for multiple “causes”, or reasons why, for a given state of affairs. What I think he really meant to assert, in the brief passage in his treatise on the soul that is taken to support this typically empiricist position, was the more modest thesis that broadly speaking, sense perception provides the event-based occasions that drive occasions of thought. That does not mean that all the content (or form, as Aristotle would call it) of thought has its most direct source in sensation, although significant parts of it clearly do.

Consider something like language. Most concrete instances of language clearly have a sensible component, and those that don’t (such as when we silently talk to ourselves) arguably could not occur if they were not preceded by other instances that did have a sensible component. Without sensation, there could be no language. But that hardly means that linguistic meaning has its primary source in sensation. One could argue that sensation is always depended upon somehow even in considerations of meaning, but it does not seem to be the primary concern. Sensation by itself is a necessary — but not sufficient — basis for an adequate account of thought.