This is about the function of ideas in Hugh MaDiarmid's poetry - ideas that came from Russia - and how they have been assimilated in Scotland.
Considering the place of existentialism in MacDiarmid's poetry, a reviewer from the Times Literary Supplement (perhaps confusing him with Seamus Heaney) once remarked:
'I very much doubt that MacDiarmid understood any of these hard matters. Or, in his truest poems, needed to. He was not, in any sense that counts, a philosophic poet. His narrative gift was lyrical and descriptive'.
Some years earlier in the same publication, the Scottish poet Douglas Dunn complained that Scottish poetry in general and MacDiarmid's in particular, almost always had some ideological axe to grind, and fought shy of the simple lyricism we find in English poetry. 'The lyric of leaf and bloom', says Dunn, 'is an extreme distance away from MacDiarmid's geological poetry, and the purposes to which he put it. MacDiarmid struggled with exercises of will in an attempt to answer the question, how to be

ourselves without interruption,
Adamantine and inexorable?

The Scottish philosopher George Davie sees the same difference between Scottish and English tendencies in verse, but he prefers the Scottish approach: of A Drunk Man Looks at the Thistle, he says that (like Anderson), MacDiarmid contrasts Scottish scepticism or pessimism, and Anglican Pelagianism with its optimism about things. He criticizes utilitarianism and the happiness-seeking philosophy from the Calvinist point of view. He won't take tradition for granted, but tries to return to first principles.
For better or worse, MacDiarmid's poetry can't get clear of ideas. The Anderson mentioned by George Davie was another Scottish philosopher, a contemporary of MacDiarmid's. Yet there is no evidence that MacDiarmid was aware of his work. Strange: in his Contemporary Scottish Studies (London, 1926) MacDiarmid makes a fairly systematic review of Scottish poetry, fiction, painting, sculpture, theatre and music - but not of philosophy. Why not?
The short answer is that David Hume, known as the greatest Scottish philosopher, had 'consistently discarded everything distinctively Scottish in matters of intellectual attitude and belief'. Furthermore, as Alasdair MacIntyre puts it, 'For Hume the rights of property are absolute. There is and can be no standard external to them in the light of which some particular distribution of property could be evaluated as just or unjust (III,ii,6). Justice on this view serves the ends of property and not vice versa. Hume presents as human nature as such, (something which) turns out to be 18th-century English human nature, and indeed only one variant of that, even if the dominant one'. MacDiarmid never had much in the way of property himself, and he had no respect whatever for property of the intellectual sort.
MacDiarmid could conceivably have turned to Hume's rivals in Scotland, Thomas Reid and the Common Sense school, and indeed George Davie argues that, whether he was aware of it or not, in A Drunk Man Looks at the Thistle he did employ procedures favoured by Thomas Reid, particularly common sense as interpersonal knowledge, that knowledge of others and of the self - that can be gained only through human intercourse, evoked in the poem in the drunk man's relationship with his wife. That is true, but not the whole truth. It must also be said that the very mention of common sense sent MacDiarmid running in the opposite direction - to Dostoevsky in fact. Since I have discussed his debt to Dostoevsky elsewhere, I will just make one point, about Dostoevsky's influence on the form of A Drunk Man, which is both an attempted national epic and a Menippean satire on such pretensions. Like Virgil in Dante's Divine Comedy, Dostoevsky is both a formal influence and a character in the poem, helping the drunk man look for the sense of life in the depths of the psyche. The formal influence shows in the very structure of the poem, which has much in common with Menippean satire, as described by Mikhail Bakhtin in his book on Dostoevsky:

Fantastic episodes and adventures whose sole purpose is the testing of philosophical ideas (often incorporated in the image of a wise man). It combines fantasy, symbolism and mystical or religious elements with coarse and primitive naturalism; often set in bars, brothels, highways etc. Academic philosophy is dropped and only the ultimate questions of ethics and practicality remain. Menippean satire shows the earliest examples of moral and psychological experimentation: the depiction of abnormal moral and psychic states, in dreams and madness, disrupting the epic and tragic integrity of man and his fate.

This definition reveals a generic link between this poem and the Menippean elements in Dostoevsky: the 'Dream of a Ridiculous Man', Bobok, Raskolnikov's dreams, and the 'Pro and Contra' section of The Brothers Karamazov.
MacDiarmid had hoped that Dostoevsky's ruthless scrutiny of motivation afforded an insight into the purpose of the individual and the destiny of the nation; but as it turns out, the Dostoevsky-Virgil analogy holds good here, too: Dostoevsky was the best guide through splintered psychology, but he could not carry through to a vision of universal purpose; his own hopes for Russia derived from the conservative utopia of the Slavophiles, which became increasingly reactionary in the last quarter of the 19th century. MacDiarmid would not follow that line.
He couldn't follow David Hume, and since he had no time for vulgar common sense he was not attracted to the philosophy of Thomas Reid; yet one thing that emerges from his recourse to Dostoevsky is that he decidedly follows the Scottish habit of going for first principles. There had been no such impressive attempt on the root of things since Hume's Treatise on Human Nature. Also, in its Menippean way of stripping away technicalities, the long poem opened essential questions to the non-specialist, and this is a feature of Thomas Reid's approach that has regained him an audience today.
Up to this point it is possible to discuss MacDiarmid's poems as if they were verse philosophy; it makes sense to talk of tradition, positions abandoned and ideas reconciled. A Drunk Man Looks at the Thistle and To Circumjack Cencrastus are long poems, and they are also philosophical investigations. The poetry of the 1930s, however, comes in smaller sections - whether or not they were originally intended to form part of an enormous whole - and attempts to read coherent philosophical positions from them run into insurmountable contradictions. Part of the problem is that throughout the 1930s MacDiarmid committed himself to mutually exclusive world views, the main ones being the metaphysics of Lev Shestov and the politics of Lenin. By the time he wrote In Job's Balances, which was the book MacDiarmid used most heavily, Shestov had come to see politics as a waste of time, while Lenin regarded metaphysicians as a waste of space. One vehemently denied the perfectibility of mankind and the other ruthlessly pursued it. There was no reconciling them, but MacDiarmid was not prepared to let either of them go. Nor can it be said that there was some misunderstanding on MacDiarmid's part, or that he was namedropping again.
One of the reasons the TLS takes such a dim view of MacDiarmid is that he was a terrible thief: his longest poem, In Memoriam James Joyce, consists almost entirely of quotation from other work, and much of that work was stolen by MacDiarmid from the pages of the TLS. This explains the fairly common tendency to dismiss awkward ideas in his poems as things he didn't really know much about anyway. Yet there is, it seems to me, a reasonably sure way of telling whether MacDiarmid really values a writer as much as he claims to: if the poetry he writes contains not only references and quotations but also structural influence, then MacDiarmid is serious. Using this acid test we see that Dostoevsky had a profound influence on MacDiarmid, and that Solovyov was a good sparring partner. The Scottish poet was serious about Lenin, and completely imbrued in Shestov's metaphysics.
Staying in Leningrad in 1980 I tried to find a translator for MacDiarmid's poems, but no one would read him because he wrote hymns to Lenin and no one would publish him because of what the Hymns to Lenin said. To be quite accurate, a handful of translations have been published in the Soviet Union, the first over 50 years ago, when D.S. Mirsky published the Third Hymn to Lenin in Novaia Angliiskaia Poezija - which was where Brodsky came across Auden - although offending lines were sanitized in translation: MacDiarmid wrote "thought is reality and thought alone" (arrant idealism, as one Scottish Marxist complains), and that becomes "thought is all-powerful". Now that there exists a fine critical edition of A Drunk Man) it should be possible to have a translation made.
In the Second Hymn to Lenin MacDiarmid repeats his commitment to Marxism, but points out that politics is merely "a pool in the sands" in the tide of poetry. Since poetry is "Unremittin', relentless/ Organized to the last degree" it is a much more serious business than politics. But first things first: give people the basics, then on to metaphysics. Thus MacDiarmid fulminates against

... those who mistake blind eyes for balanced minds,
Who practise, in Disraeli's words,
'The blunders of their predecessors'.
People to whom experience means nothing,
Whose souls exist in a state of sacred torpidity,
Prostrated before cold altars and departed gods,
Whose appeal to commonsense is only an appeal
To the spiritual sluggishness which is man's besetting sin,
And in the present unexampled crisis our deadliest peril.

In Whose Justice? Which Rationality?, Alasdair MacIntyre attempts to bring some coherence to the ethical debate, concerned as he is by 'the type of self which has too many half-convictions and too few settled coherent convictions, too many partly formulated alternatives and too few opportunities to evaluate them systematically, so that it brings to its encounters with the claims of rival traditions a fundamental incoherence which is too disturbing to be admitted to self-conscious awareness except on the rarest of occasions.' (p.397) This is clearly a perception of the same fear from another side. MacDiarmid's view of the sufferers is much less sympathetic:

Anywhere you go in Britain today
You can hear the people
Economizing consciousness,
Struggling to think and feel as little as possible,
Just as you can hear a countryside in winter

Crepitating in the grip of an increasing frost. (The Battle
Continues, CP 938)

Both MacIntyre and MacDiarmid attempt ambitious solutions to the problem: MacIntyre by proposing a framework in which people can begin to recognize and resolve their problems, and MacDiarmid by the incendiary method: destroying the makeshift ideologies people shelter in - beginning with his own.
MacDiarmid repeatedly referred to Lev Shestov as his master. According to the acid test, he was not joking. MacDiarmid first refers to him in 1922; he was still quoting him in 1962, in his pamphlet on David Hume.
There is a wonderful moment in the Treatise when Hume quietly dismantles causality. Kant wrote that Hume had awakened him from dogmatic slumber, prompting him to write, 'That my will moves my arm is to me no more comprehensible than if someone should say that it could hold back the moon itself'. But then, Shestov complains, 'Kant exiled the wonders, in order not to be forced to see them, into the field of the "thing in itself", and bequeathed to mankind the "synthetic a priori judgments", transcendental philosophy, and his three miserable "postulates"'. This is the moment MacDiarmid refers to in his poem 'Thalamus':

'The truths that all great thinkers have seen
At the height of their genius - and then
Spent most of their days denying
Or trying to scale down to mere reason's ken ...

O misguided science pursuing
All tasks but the greatest of all
While away beyond this life's scant scope
In a glorious unseen waterfall
Pours all but all of life's best
We turn our poor mills with the rest.

These mills of Satan; these hellish hives
In which men sink to the status of slaves,
Treadmills of rationalizing . . .' (CP 413)

Far from censuring Hume's scepticism, as the Common Sense philosophers did, Shestov and MacDiarmid criticized Hume for not carrying it through. Why?
For Shestov, the fruit of the tree of knowledge was fear of liberty: man had to have to do things, we need necessity, causality, law, ethics, universal truth, because otherwise we wouldn't know what to do, and we need to know, and what we all know has to be the same for everybody, otherwise it wouldn't be right, would it? This is the way we build ideological prisons for ourselves, accommodating even God; this is common consciousness, omnitude, as Dostoevsky's 'vsemstvo' is translated.
With his critique of causality Hume had blown a hole in it, which Kant quickly repaired. MacIntyre notes, "Even the law of noncontradiction as formulated by Aristotle has encountered thinkers both sufficiently ingenious and sufficiently wrongheaded to deny it." If you want to build an ethical structure, you need to believe that actions cause consequences, and that a thing cannot be both A and not A at the same time. Unfortunately, these tenets do seem to be a matter of convention, and there will always be awkward philosophers like Shestov to point that out. Of course there is another group of practitioners who regularly refuse to call a thistle a thistle, and who feel free to call it a Russian novelist, or a nervous system, or a volcano or a map. Because the law of metaphor is as fundamental to poets as the law of non-contradiction is to philosophers. MacIntyre the moral philosopher and MacDiarmid the poet both discern a crippling fear of chaos in humanity; MacIntyre tries to subjugate the chaos, MacDiarmid to overcome the fear.
It was in the 30s, in Stony Limits and Other Poems, that MacDiarmid was most taken up with Shestov, and the attendant dangers are to be seen in the "Ode to All Rebels",, where a magnificent call to rebellion rises to an impossible pitch, calling for the removal of every stricture of opinion, finance, reason, sanity, law, science and even language - which would make victory an empty word, as the rebellious voice acknowledges.
If the "Ode to All Rebels" relinquishes reason and pursues human emotion to extremes, "On a Raised Beach" takes the opposite tack, and has reason pursue emotion to extinction. But Shestov is still there:

Truth is not crushed;
It crushes, gorgonizes all else into itself" (CP430)

The intuition that dead, universal Truth is inimical to human desires is as central to Shestov's philosophy as it is to this poem. And Shestov is quoted..

... These stones are one with the stars.
It makes no difference to them whether they are high or low,
Mountain peak or ocean floor, palace or pigsty. (CP 425)

That's from In Job's Balances, p.189.

"I know there is no weight in infinite space,
No impermeability in infinite time, ... (CP 432)

Compare that to Shestov: 'Before the face of Eternal God all our foundations break together and all ground crumbles beneath us, even as objects - this we know - lose their weight in endless space, and - this we shall probably learn one day - will lose their impermeability in infinite time. Not so long ago weight seemed to man an inseparable attribute of things, even as impermeability.'
In that part of the book, Shestov observes that the anthropomorphic thinking implicit in ascribing a purpose to nature (that of preserving the organism, for example) is inconsistent with science's pretensions to objectivity. In 'On a Raised Beach' MacDiarmid tries to eradicate that anthropomorphism, to feel the world the way a lump of rock does.
Well, if the Hymns to Lenin were full of arrant idealism, 'On a Raised Beach' is rather too thoroughly materialistic. Lenin, putting the materialist case, describes 'sensation, thought, consciousness as the supreme product of matter organized in a certain way'. Shestov shows that that adjective 'supreme' is anthropomorphic idealism; from a strictly materialist point of view, one configuration of matter is no better than another.
Not that Shestov would have recognized his own ideas in MacDiarmid's poetry: when Shestov attacked the legacy of the Greeks, he drew on Jewish tradition; his disciple Benjamin Fondane did the same, so that the line he took is comparable. However, when Shestov's methods are applied by a French ex-Catholic like Georges Bataille, or a Scottish ex-Calvinist like Hugh MacDiarmid, the results are quite different. MacDiarmid seemed to use antirationalism to get him above humanity, away from any vestigial common sense.
Something was happening to him. He had a severe breakdown around that time. His autobiography finds him, as he says, 'with my back to the wall, pleading quietly for power 'to stay in no retreat and not to die' acknowledging chaos with a candour which cannot evade fear, but seeking refuge neither in an irrecoverable way of life nor in oblivion'. He quotes a testimonial to himself by other writers then rounds on them as a bunch of hypocrites, and he judges himself as follows: 'Faustus-like, I have tried to encompass all experience, and find myself at last happy enough marooned on this little island of Whalsay and only very slightly, I think, in any relevant respect, a failure' The TLS reviewer I quoted at the outset found this book 'self-serving rather than self-revealing'; to me, all the ritual boasting it contains bespeaks shattering self doubt, a condition that was compounded by total neglect.
Shestov clearly did have the desired liberating effect on MacDiarmid's imagination:

And everywhere without fear of Chestov's "suddenly",
Never afraid to leap, and with the unanticipatedly
Limber florescence of fireworks as they expand
Into trees or bouquets with the abandon of unbroken horses",
Or like a Beethovian semitonal modulation to a wildly remote key,
As in the Allegretto where that happens with a jump of seven sharps,
And feels like the sunrise gilding the peak of the Dent Blanche
While the Arolla valley is still in cloud. (CP 1020)

He overcame the fear, but not the chaos. The poetic persona retreats among.the quotations, dwindling at times to a grammatical ghost. The quotations and ideas are no longer assimilated or taken on by a central persona. Shestovls ideas, instead of providing direction and unity as the Dostoevskian search had done, allowed MacDiarmid to disengage from consequences, logical, social or linguistic. Ideas succeed one another in an exhilarating, exasperating and exhausting series of highs. As MacDiarmid himself put it in In Memoriam James Joyce,

As a poet I'm interested in religious ideas -
Even Scottish ones, Wee Free ones even - as a matter of fact
Just as an alcoholic can-take snake venom
With no worse effects than a warming of the digestive tract.
(CP 798)

He is like a stock market trader who has turned from shares in tin to treating money as a commodity. It can be done, but it is a practice which must slacken one's grip on the real world. Foreign texts and other facts were the commodities MacDiarmid was dealing in.In his late, agglomerative poems these texts are linked analogically: logical sequences tend to be within quotations, and he was quite happy to leave contradictions inside and consequences outside his poems for the readers to worry about. The present reader has long since stopped worrying about the contradictions, but there are consequences that bother me, such as the poem 'To a Friend and Fellow-Poet':

To a Friend and Fellow-Poet

It is with the poet as with a guinea worm
Who, to accommodate her teeming progeny
Sacrifices nearly every organ of her body, and becomes
(Her vagina obliterated in her all-else-consuming
Process of uterine expansion, and she still faced
With a grave obstetrical dilemma calling for
Most marvellous contrivance to deposit her prodigious swarm
Where they may find the food they need and have a chance in life)
ALmost wholly given over to her motherly task,
Little more than one long tube close-packed with young;
Until from the ruptured bulla, the little circular sore,
You see her dauntless head protrude, and presently, slowly,
A beautiful, delicate, and pellucid tube
Is projected from her mouth, tenses and suddenly spills
Her countless brood in response to a stimulus applied
Not directly to the worm herself, but the skin of her host
With whom she has no organised connection (and that stimulus
O Poets! but cold water!) ... The worm's whole musculocutaneous coat
Thus finally functions as a uterus, forcing the uterine tube
With its contents through her mouth. And when the prolapsed uterus ruptures
The protruded and now collapsed portion shrivels to a thread
(Alexander Blok's utter emptiness after creating a poem!)
The rapid drying of which effectually and firmly
Closes the wound for the time being... till later, the stimulus being reapplied,
A fresh portion of the uterine tube protrudes, ruptures, and collapses,
Once more ejaculating another seething mass of embryos,
And so the process continues until inch by inch
The entire uterus is expelled and parturition concluded.
Is it not precisely thus we poets deliver our store,
Our whole being the instrument of our suicidal art,
And by the skin of our teeth flype ourselves into fame?
(CP 1057-8)

The juxtaposition of the Guinea worm with Blok's writing habits is striking, but more striking yet is use of the Guinea worm as some kind of ideal. Mention it to most people and they will tell you it is one of the more noisome plagues of humanity: the larvae enter the human body in infected drinking water, and make their way to the mesentery. After mating and about a year's gestation, the female, about a yard long by this stage, burrows down towards the feet and a blister forms on contact with water, from which the larvae, and then the worm, emerge. The process is accompanied by much pain, nausea and vomiting (on the part of the human host). You wouldn't know from MacDiarmid's poem; a very anthropocentric complaint, you may say. Yes indeed, but then I am an anthropos. It seems to me that MacDiarmid's contempt for common consciousness brought him close to contempt for common humanity. His political poems show the same tendency.
Scottish writers since have tackled the problems he raised. Alasdair Gray in his novel 1982, Janine goes directly to A Drunk Man Looks at the Thistle and Dostoevsky's Notes from Underground, and the picture of the Scot he paints is one that few would want to recognize. Yet when it comes to fear of chaos, his choice, like MacDiarmid's, is to kill the fear. The central character at the end is ready to face himself, whatever the result. If the result is his latest novel, Something Leather, then Gray, like MacDiarmid, is showing us that genius and immense courage are not enough to get us on the right road. The novelist James Kelman follows George Davie in advocating a return to common sense philosophy, attempting to subjugate chaos to human control. But then, as Alasdair MacIntyre points out, what discredited Thomas Reid's philosophy in the United States immediately before the Civil War was its inability to account for radical moral disagreement within a single cultural and social order. If the fearless individual can't win clear of chaos and common sense can't resolve it, then where is the answer? That is the question.