I think Berkeley's approach is actually quite sensible (no pun intended): can't reconcile Body and Mind, can't get rid of Mind, so get rid of Body.
And Hume is now:
The pinnacle, or perhaps the nadir, of Empiricism was reached with David Hume, generally considered the greatest English-language philosopher. Although Hume was born into a devoutly Calvinist family, and was as a young man somewhat fixated on religious questions, his time at Edinburgh University (which he entered at the age of twelve) introduced him to the Classics, and rapidly turned him from organised religion. Some have argued that he was a deist, but it seems likely that this was merely an acceptable face for his (almost unprecedented) atheism, which caused him considerable political trouble throughout his life. He was only truly accepted on his sojourns to France, and at home he became famous and rich only with the publication of his seminal History of England, not for his philosophy. Atheism, however, was only one facet of an overarching iconoclasm; many of his critics accused him of trying to be original for originality’s sake, in every field, while he himself described his philosophical mission, with Calvinist zeal if very different direction, as “to destroy the false and adulterate”.
Most of Hume’s points flow from his theory of perceptions. It is his belief, as an Empiricist, that all perceptions (ideas) originate with sensation, as ‘impressions’. These impressions decay or fade over time, turning from lively impressions into pale ‘ideas’. To begin with, they are simple ideas, but they may be combined by mental faculties into complex ideas. Hume believes that error and confusion arise when we reason with ideas so complex, and so far from our impressions, that they have become weak, pale, and vague. Some of them, indeed, have lost all meaning, because no clear connexion to the impressions can be found. The remedy to this is therefore to take careful stock of our words, finding for each one the idea it corresponds to, decomposing that complex idea into simple ideas, and tracing how those simple ideas originate in impressions.
Hume’s view of the mind is not as something active and spiritual, but as something mechanical and largely passive; he believes he is beginning a new science of human understanding analogous to the physical sciences. Accordingly, many difficult mental characteristics are reduced to simple phenomena. “Belief”, for instance, is not, for Hume, any sort of particularly representative or intentional state, but simply an unusual vivacity that is held by particular ideas, which makes them seem more like impressions (and hence makes them clearer and harder to deny). “Truth” is not built from certain foundations at all: instead, a “reality” is formed from our vivacious beliefs and our current impressions, and this system can be, or not be, “coherent”.
Moreover, although he acknowledges that ideas represent things, and that the truth of an idea comes from correctly representing the thing, Hume takes a dramatic step: for him, ideas only represent the impressions they were formed from. A true idea mirrors an impression; a false one, does not. Impressions do not represent anything, and are therefore neither true nor false. As to the ‘source’ of the impressions, Hume is agnostic – maybe they arise from some ‘external’ ‘objects’, maybe they are conjured up by some imaginative faculty, maybe they are given to us by God. He doesn’t know, and doesn’t care – all attempts to know are illegitimate, as they go beyond any evidence we can collect.
However, unlike Locke, he believes the mind has more than just these impression-derived ideas. The mind, he says, has a tendency or habit to connect particular ideas with each other, in relations of causality, contiguity, and resemblance. These ‘judgements’ create a second tier of impressions, but they cannot be reduced solely to impressions (that is, their content can be, but their origins cannot). Instead, the connective faculty of the mind must simply be accepted on its own terms.
Rationalists would say that this connective faculty was Reason, or a part of Reason, but Hume denies this. He divides reasoning into two types: reasoning about matters of fact, and reasoning about the relation between ideas, by which he means what we call ‘analytic’ reasoning. This brings out aspects already found in the ideas themselves. So, “bachelors are unmarried” is analytic, in that it tells us nothing not contained in the word “bachelors”; likewise, he accepts that “2+2=4” is analytic. It is also a priori (does not require experience) – here he accepts Rationalism, unlike Locke. But it is a poisoned acceptance – because he believes that everything a priori is analytic, and therefore such ‘reasoning’ can tell us nothing about the world, and nothing about our impressions, but merely tautologically reminds us of what the ideas we have actually mean. Causal association is not reasoning in this way, because the effect is not inherent in the cause, but must be learnt by experience.
Moreover, causal association cannot come from ‘matters of fact’, either, as no array of particular sense impressions can ever tell us anything universal. We ‘reason’ about the past and future through induction – the principle that the future will be the same as the past – but that principle cannot itself be known from impressions (we cannot experience the future: we can learn that what-was-the-future was the same as what-was-the-past, but the idea that that relation will still hold in the future requires induction, which begs the question). So either we accept the validity of some innate knowledge (in this case the temporal uniformity of physical laws), or we acknowledge that inference is not rationally valid, and that causal reasoning is not a form of reasoning at all. As Hume could not see how innate knowledge was possible (all knowledge being knowledge of the impressions, and derived from that source), he took the latter option.
Causality, then, was not some inevitable property of the universe, which could be known about innately. Instead, causality was our word for a particular habit we have got into of associating two events, when we have noticed that the one event is commonly seen to precede the other event. This definition finally eliminated the Mind/Body problem for Empiricists – because it got rid of all suppositions about the nature or cause of causation (there must be contact, there must be some sort of interaction, etc), it said that any two things that happened to occur contiguously in time could be called cause and effect, and so there was no obstacle to Mind and Body ‘interacting’ with each other. There was no difference between causation and parallel action – essentially, for Hume, causation actually IS correlation.
This is far from the limit of Humean radicalism. In general, Hume casts doubt on all attempts to move from the particular (eg juxtaposition of two events) to the general (eg laws of causation). He does the same thing with substances and underlying objects that persist through time. Shockingly, he even applies the principle to the self. Descartes believed that “I think, therefore I am”, but Hume disagreed: Descartes had an idea of thinking, yes, and by convention ascribed that thought to a thinker. Fine. And he did that time and again – but none of that is enough to make the leap to saying that the “I” in each case represents some common thing. There is no enduring “I”; there is no “self”. There is only a series of mental phenomena, which by habit we connect by attributing them all to a single experiencer.
Hume also had controversial views of morality. He, as usual, opposed Rationalism, which was even more commonplace in morality than in other fields (Locke himself remain a rationalist about morality): rationalism believes that, fundamentally, good and bad actions can be reasoned about, and that acting badly is therefore irrational. Hume rejects this entirely, for this ‘reason’ is neither about the relations between ideas nor about matters of fact. He observes, famously, that accounts of morality frequently begin with matters of fact, using the verb ‘is’, and then suddenly jump, without any logical connexion, to matters of morality, using the verb ‘ought’. Instead, he says, reason can only be employed in deciding the most practical means: “reason is, and can only be, the slave of the passions”. Ends themselves cannot be assessed against reason: there is nothing irrational, he says, in a man preferring to let the entire world be destroyed, rather than lift his finger.
Instead, morality is focused not on actions but on traits – specifically, traits that are ‘useful’ (or which rationality is presumably one). In this, he appears to be following Hobbes, who grounded morality in self-interest, but Hume refutes this view through appeal to daily experiences. It is simply not the case, he thinks, that our everyday moral feelings can be explained purely by self-interest. Instead, the basis of morality is ‘sympathy’, or ‘benevolence’, by which we feel the pain and pleasure of others. This is not an accidental quality, however, but an inevitable product of communal life: because we need to live with others, we need a common, and hence non-particular, language, and that language shapes our associations: because we call it ‘pain’ whether it is mine or yours, there is a commonality in our feelings about both types of pain, which is re-enforced by the same associative faculties that give us ideas of universality, and causality.
Hume’s views were both fruitful and depressive in their power. On the one hand, his views inspired his friends and his readers to new advances – Adam Smith is an example of the former, and Darwin of the latter. The importance of his contributions to philosophy, history, politics, religion, and economics (where he pioneered theories of free trade) cannot be overlooked: he was the towering figure of the so-called Scottish Enlightenment, and posthumously played an enormous role in shaping the identity and worldview of the British Empire. One 19th century Englishman summarised his significance: “Hume is our Politics, Hume is our Trade, Hume is our Philosophy, Hume is our Religion.”
At the same time, however, there was something both frightening and final about Hume’s philosophy, in which Empiricism sealed the last bolt in its own coffin. The grand attempt to justify and explain all human knowledge from experience had only succeeded in eliminating virtually all knowledge that people thought they had: about themselves, about God, about morality, about the external world, about science, about causality… about everything. Hume seemed to say that we could do without these things… but even he admitted that, faced with the sceptical nihilism of his theories, he was occasionally overcome by depression, which he could only escape by leaving his books behind, going to a party, and playing backgammon instead. Science continued, of course, but philosophers were left behind, unable (until the twentieth century, and Popper’s theories of falsification) to find any rational justification for it. Empiricism, having eliminated most of the universe and of human thought, had literally nowhere left to go – although there was a period of denial, Mill’s attacks on Hume’s critics drove the point home, and the empirical tradition in Anglo-America died out (though its influence later reawoke in some branches of Analytic Philosophy in the twentieth century).
The silence Hume engendered in some quarters would not have displeased the man himself, who seems to have believed that silence (or backgammon) is better than "adulterate" reasoning. In one of his most famous quotations, he makes clear with characteristic force what he thinks of such speculation:
"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."
Hume’s most important work is generally considered to be the Treatise of Human Nature; sections of it were reworked, condensed, and made more understandable in the Enquiry Concerning Human Understanding and Enquiry Concerning the Principles of Morals. In general, Hume is an easy read if the language of the era is not off-putting – he combines a simple, conversational style with a marvellous turn of phrase and a fine sense for prose rhythm, and in my view is one of the greatest English stylists, although this can distract from the content – I remember reading paragraphs of his works, just listening to how they sounded, before realising I hadn’t paid attention to anything they said.
In tone and content, Hume’s works, not only the more serious but also the more popular essays on a variety of subjects, have become central to modern civilisation, and in particular to the ideal of “Britishness” – civil, polite, anti-authoritarian, allergic to vanity, underscored with irony and a potentially sharp wit, and never frightened to disagree. Some quotes gleaned at a glance from the internet to illustrate this worldview:
“Truth springs from argument between friends”
“Avarice, the spur of industry”
“When men are the most sure and arrogant, they commonly are the most mistaken”
“Eloquence, when in its highest pitch, leaves little room for reason or reflection”
“Generally speaking, the errors in religion are dangerous; those in philosophy only ridiculous”
“The Christian religion not only was at first attended with miracles, but even at this day cannot be believed by any reasonable person without one”
“I have written on all sorts of subjects . . . yet I have no enemies; except indeed all the Whigs, all the Tories, and all the Christians”
“The heights of popularity and patriotism are still the beaten road to power and tyranny; flattery to treachery; standing armies to arbitrary government; and the glory of God to the temporal interest of the clergy”
“The great end of all human industry is the attainment of happiness. For this were arts invented, sciences cultivated, laws ordained, and societies modeled, by the most profound wisdom of patriots and legislators. Even the lonely savage, who lies exposed to the inclemency of the elements and the fury of wild beasts, forgets not, for a moment, this grand object of his being.”
But the river tripped on her by and by, lapping
as though her heart was brook: Why, why, why! Weh, O weh
I'se so silly to be flowing but I no canna stay!