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現實與對現實的認知 ----- Brian Gallagher
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0. 前言
《航行者》網誌的嘉樂格先生訪問認知大腦神經科學家汀默曼教授後，對後者研究成果做了報導(下稱「原文」)。轉載於下。龐羅愛先生就同一主題在另一篇報導中有一段他對此研究的「詮釋」。本欄將轉載龐羅愛先生的文章和另一篇相關報導。此外，英國《衛報》也報導了汀默曼教授的研究，此處從略。
這些報導的詮釋中有些文字可能導致嚴重的誤解。因此，我將翻譯原文於下(第1節)；略表拙見並討論相關議題(第2節)。下文中引號與紅色、淺藍色兩種字體是我用來強調和醒目，譯文部分超連接是我加上以供參考。
1. 汀默曼教授研究報告
1.1 N,N-二甲基色胺 (DMT) 實驗結果(原文第1節第1、2兩段)
參與此項實驗的人在服用DMT後，覺得自己進入另一個空間；她/他感到這個不同的世界出奇的真，比日常生活世界還要真，並且感受到一種精神或心靈的召喚。在我們最近進行的實驗中，我們用「功能性磁振攝影」和「腦電波紀錄圖」兩種技術觀察被實驗者的大腦動態。上述與環境融為一體的感覺，似乎來自「大腦各部位間的失調」。上一句話中的「部位」指處理規劃、決策、和了解語意的「前額葉皮質區」與「顳葉皮質區」兩處；也就是人腦中決定「意義」的部位。
人腦通常在各司其職、有條不紊、分層負責的形勢下運作；在我們成長過程中，人腦逐漸形成界線分明的不同網絡和次級系統。在DMT被實驗者的大腦中，處理人們複雜行為和任務的大腦各部位不再以分工模式運作；而與大腦其它部位變成渾然一體。各司其職被擾亂，分層負責被打斷，造成大腦中各神經網絡間的連接度大幅升高。
1.2 DMT建構出全新的經驗世界(原文第2節第1、2、3三段)
在日常生活中，大腦中處處理我們身體內外訊息的感官有清楚明確的界線。但在DMT影響下，這兩部分的界線變得模糊不清。處理身體內外訊息的感官攪和在一起，相關的神經細胞被同時啟動。
在DMT影響下，人們看到重疊的影像。她/他們無法處理從外部世界收到的訊息，這種經驗讓參與實驗者感到震撼。她/他們感到自己處在一些活生生的個體中 – 致幻劑次文化中它們被稱為「機器精靈」。這是服用DMT者特有的經驗；此經驗在服用LSD和神奇蘑菇者中並不常見。
我們實驗團隊就此現象所做的「假設」是：DMT使用跟記憶、語意、和意義形成相關的大腦部位和系統，建構了一個「經驗世界」。我們找到了一些證據「支持」這個想法；例如：人們在睡夢中也靠這些類似的機制 – 如使用顳葉系統和緣腦系統 -- 產生「經驗世界」。我們之所以對DMT有興趣就在於：基本上它在不影響覺醒狀態下改變人們的意識經驗。
1.3 從DMT經驗學到的結論(原文第2節第4、5兩段)
如果我們做適當的解讀，從致幻劑經驗所得到一個相當有趣的結論是：這類經驗讓人們質疑「簡單現實論」；後者指：我們能直接如實的觀察外在世界這個觀點。致幻劑經驗讓人們感覺到外在世界其實是一個我們在腦海中建構的一個模型。或者說，致幻劑直觀的顯示：現實是建構出來的幻象。
不久之前，我們(實驗團隊)思考過：在有了DMT經驗後，人們對現實性質的「形上學式觀點」會產生多大的改變。我們發現：在僅僅服用DMT一次後，人們會質疑現實具有物質性質或具體性質的說法；她/他們會比較傾向：「泛心靈說」這類世界萬物都有意識的觀點。這種想法很自然的與多數宗教人士觀點契合。例如：在服食死藤水(含DMT)來和通靈世界溝通的文化中，人們認為精神無所不在；她/他們認為植物也有靈性。
2. 現實與幻覺是兩碼子事
由於嘉樂格先生原文語焉不詳，也沒有使用引號，我無法確認那一部分是汀默曼教授對自己研究的「詮釋」，那一部分是嘉樂格先生對談話內容的「解讀」。根據龐羅愛先生報導直接引述汀默曼教授的觀點來看，原文中大部分是教授自己的「詮釋」。
2.1 實驗對了解「意識」的貢獻
該實驗的確增加了我們對「意識」的了解。上文第1.1小節第2段：
「在DMT被實驗者的大腦中，處理人們複雜行為和任務的大腦各部位不再以分工模式運作；而與大腦其它部位變成渾然一體。各司其職被擾亂，分層負責被打斷，造成大腦中各神經網絡間的連接度大幅升高。」
這個實驗告訴我們：幻覺產生的原因是：「大腦中各神經網絡間的連接度大幅升高」的結果；或腦熵指數狂飆導致幻覺(見本欄第2篇龐羅愛先生的報導)。
2.2 「行動者錯置謬誤」
以上第1.1小節和第1.2小節第1、2兩段文字，內容中規中矩，也符合人們對「致幻劑作用」實驗的預期。相形之下，第1.2小節中第三段的文字則自由聯想過了頭；或犯了「擬人化」所衍生的「行動者錯置謬誤」。
「行動者錯置謬誤」指的是：
在「擬人化」後，一個人忘了：「只有『有意識』的個體才有『行動能力』」；從而把「被『擬』的個體」當做「行動者」。
為了幫助說明這個「謬誤」，我把以上第1.2小節第三段話意譯並加修改如下：
「我們實驗團隊就此現象所做的「假設」是：服用DMT後，使用者處理記憶、語意、和意義形成的大腦部位和系統，受到DMT的干擾，導致使用者在腦海中形成一個虛擬的或幻想出來的『經驗世界』。人們在日常生活中也有這種經驗；例如：人們在睡夢中也因為這些類似的機制 – 如顳葉系統和緣腦系統內神經細胞的自然啟動 -- 產生『非真實性的經驗』。我們之所以對DMT有興趣就在於：基本上它能在覺醒狀態下讓人產生和做夢類似的經驗。」(修改部分根據我對大腦運作的了解。)
各位比較上述第1.2小節中我對原文第2節第三段文字的「直譯」和「意譯 + 修改」，就看得出汀默曼教授所提出「假設」的爭議是：
DMT不會「使用」人體大腦部位，更不會「建構」人的經驗。
服用DMT後造成幻覺的原因是：DMT進入腦血管後和腦神經細胞產生化學作用，此作用啟動大量的腦神經細胞，導致大腦內同時產生種種影像而看到幻覺。
2.3 凡所有相皆是虛妄
《金剛經》中的：「凡所有相，皆是虛妄」的「相」是人們通過感官和大腦內部相關神經細胞作用後對現實產生的「認知」。它相當於康德的「表象」或「現象」，而不相當於康德的「物本體」。
因此，《金剛經》這句話並不是說：「現實是虛妄的」；它說的是：
「(人們)對現實的『認知』並不可靠」。
本欄第二篇文章倒數第2段的第一句話：「一般而言，我們對現實的認知是大腦建構的」。這句話相當正確，可惜很多人無法了解：
「對現實的『認知』」並不相當於「現實」(該文第2節)。
例如，相信「泛心靈說」者的錯誤就在於：把「對現實的『認知』」視為「現實」。
「對現實的『認知』可以被建構」並不相當於「現實『具有』被建構性」；更完全不等於「現實『可以』被建構」。
本欄轉貼三篇文章中，某些「詮釋」可能引起誤解的原因，就在許多人不能分別「現實」和「對現實的『認知』」。
What Happens to My Brain on the Psychedelic DMT?
One question for Christopher Timmermann, a cognitive neuroscientist at Imperial College London
BRIAN GALLAGHER, the Nautilus, 03/20/23
Explore one question for Christopher Timmermann, a cognitive neuroscientist at the Centre for Psychedelic Research at Imperial College London, where he leads the DMT Research Group and focuses on the nature of consciousness.
The DMT experience is one in which people report going into a different dimension, an alternate reality that feels convincingly real, even more real than this everyday reality. One that has a spiritual significance. In that DMT experience, they sometimes encounter beings. In our latest study we looked at brain scans using fMRI and EEG, and found that this feeling of immersion appears to be underpinned by a dysregulation of the systems in the human brain -- in the prefrontal cortex, in the temporal cortices -- involved in planning, decision making, and semantics. The way in which we construct meaning, essentially.
The brain usually functions in this modular, organized, hierarchical way. You have different networks and systems that crystallize as we grow older. What we see with DMT (specifically N,N-Dimethyltryptamine) is that the systems that generate complex behaviors and tasks stop working in this specialized fashion. They start to work in synchrony with the rest of the brain. The specialization is interrupted. The hierarchy is dysregulated, flattens out. What you have as a result is a more integrated connectivity in the brain.
DMT constructs a world of experience.
In our day-to-day lives, we have a very good demarcation of what happens inside us versus what happens outside. The sensory areas of the brain that allow us to engage with the external world are very much separated from the reflective areas of the brain that allow us to engage with ourselves. Not on DMT. What we see is that this separation, that usually divides these two poles of organization of the brain, starts to mesh together. The neurons are firing in sync.
On DMT, when people open their eyes, they see images overlaid literally in front of their eyes. They cannot engage with the external world. It’s a very overwhelming experience. This is partly what makes DMT experiences distinct from other psychedelics. The notorious feeling of being in the presence of other living entities -- “machine elves” in Western cultural memes -- doesn’t appear to be that common with LSD and psilocybin, for instance.
Our hypothesis is, by using areas and systems of the brain related to memory, semantics, and meaning-making, DMT constructs a world of experience. We found some evidence supporting that idea, that we are involving these similar mechanisms that operate, for example, when people are dreaming, which also engages the limbic and temporal systems of the brain related to the way in which we build up a world of experience. We are interested in DMT because it produces an alteration of conscious experience without changing wakefulness, essentially.
One of the most intriguing lessons from psychedelic experiences in general, for many people, if taken in the right context, is that they can perturb their naive realism -- the assumption that we perceive the world directly as it is. They can experience how the world is a model we’re constructing in our brains. This is reality as a constrained hallucination. Psychedelics intuitively show that.
Not long ago, we looked at how much what we call “metaphysical beliefs,” beliefs about the nature of reality, change after these experiences. We found that after a single trip, people are more likely to reject the notion that the nature of reality is material or physical. They endorse the belief more that everything in the universe is conscious -- the notion of panpsychism. This is, of course, very resonant with many religions. In cultures that use Ayahuasca, which contains DMT, to communicate with the spirit world, for example, the essence of the spiritual is present in nature everywhere. They speak about the spirits of the plants.
本文於 修改第 7 次
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DMT與幻象 -- Louis O’Neill
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Do psychedelics let us visit other dimensions, or is it all merely a figment of our imagination?
WORDS BY LOUIS O’NEILL
Having worked in the cannabis industry for several years, it wasn’t uncommon for me to brush shoulders with people working in psychedelics. And while I considered cannabis to be underutilized from a medicinal perspective, the plant didn’t fascinate me nearly as much as psychedelics did and still do. As an adolescent, I would regularly listen to the late Terence McKenna, the nasal-voiced lecturer and psychonaut who would speak at length about his experiences with various psychedelic compounds. To me, McKenna’s most fascinating talks are those he gave about the ‘self-transforming elf machines.’
The machine elves, according to Terence, are entities that one encounters when they consume the requisite amount of Dimethyltryptamine—or, more commonly, DMT.
Here is Terence’s description of the beings:
‘You pass through a membrane of some sort, and you’re in a place. You’re pushed through, and you see the tykes, as I call them. The self-transforming machine elves that are singing in a hyperdimensional language. They surround you and say, “Welcome, we’re so glad to see you.”’
Using language, Terence says, these elves transform themselves and the objects surrounding them, in a fluorescent playpen of hills and flashing lights. Upon hearing this, it’s easy to dismiss this description as mere drug-fuelled delusions, and they very well could be. However, what is perhaps most compelling about Terence’s description of these elves is that he’s not the only person to have encountered them.
Between 1990-1995, the first-ever U.S. study into psychedelics was undertaken at the University of New Mexico by Dr Rick Strassman (interview with Strassman later in the week), an associate professor in psychiatry. In these studies, Strassman administered DMT to 60 volunteers in a clinical setting and recorded his findings in his magnum opus, DMT: The Spirit Molecule. In the chapters entitled ‘Contact Through the Veil’ parts one and two, Strassman details the recurrent encounters that the volunteers experienced upon consuming DMT. Speaking on the bizarre reports of extra-terrestrial encounters by his volunteers, Strassman said:
‘I was familiar with Terence McKenna’s tales of the “self-transforming machine elves” he encountered after smoking high doses of the drug… I admittedly chalked up these stories to some kind of West Coast eccentricity. Therefore, I was neither intellectually nor emotionally prepared for the frequency with which contact with these beings occurred in our studies, nor the often utterly bizarre nature of these experiences.’
His book then goes on to describe various entities met by his volunteers while in the DMT realm, including elves, insectoids, reptilian humanoids, and clowns to name just a few. Some of the volunteers were welcomed by these entities with open arms and a loving embrace, others were plunged into a dystopic world, in which experiments were performed upon them. What is most interesting to me about these reports is that many of the volunteers described similar beings, without having spoken to each other about their experiences.
So, do humans tend to conjure up similar images when administered DMT? Or are we actually visiting a place where these beings exist? A study published last year in The Journal of Psychopharmacology surveyed 2,561 adults about their encounters with entities on DMT and 81 per cent of respondents described their encounters as being ‘more real than reality.’ Just 9 per cent of respondents to the study believe that the beings existed ‘completely within myself.’
During my time working with the cannabis industry, I was fortunate enough to interview Dennis McKenna—brother of Terence—an esteemed psychonaut in his own right. In our discussion, I asked Dennis whether he thought these recurrent visions or motifs of elves, mantises and other entities seen on DMT were simply archetypes that existed within the human mind, or whether he considered them to be autonomous beings that we gained access to through these psychedelic compounds. He responded:
‘That’s the $64 million dollar question right there—is it another dimension? [Terence and I] were convinced that it was a portal into another dimension. But now, I think it’s impossible to say. I think these are archetypes, but the crux of the question is, is it another place? It certainly has that feeling about it.’
Dennis is right, it is impossible to say whether these entities are real or merely figments of our imagination. But perhaps as our understanding of psychedelics grows we may be able to conclusively answer this question in the coming decades.
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DMT對大腦的作用 ---- Ross Pomeroy
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The psychedelic DMT causes the brain to become hyperconnected, scans reveal
A new study provides the most detailed look at brains on psychedelics to date.
KEY TAKEAWAYS
* Researchers gave 20 healthy subjects potent, intravenous doses of the psychedelic DMT and observed their brains with both functional MRI and electroencephalography.
* They witnessed the brain's business-like hierarchical organization collapse, replaced with a state of global hyperconnectivity. Brain entropy, defined as "the number of neural states a given brain can access," skyrocketed.
* It's commonly said that our perception of reality is constructed by the brain. DMT and psychedelics in general make this abundantly clear.
Ross Pomeroy, the Big Think, 03/31/23
N,N-dimethyltryptamine (N,N-二甲基色胺), more commonly known as DMT, is one of the most powerful psychedelics (致幻劑) known to humankind.
“The DMT experience is one in which people report going into a different dimension, an alternate reality that feels convincingly real, even more real than this everyday reality. One that has a spiritual significance,” Christopher Timmermann, a cognitive neuroscientist at the Centre for Psychedelic Research at Imperial College London, told Nautilus in an interview.
In this immersive and intense altered state of consciousness, users are fully awake. They will see vivid and vibrant imagery overlaid in front of their eyes, and even encounter sentient beings with whom they can have deep conversations. Unlike other psychedelics such as LSD or mushrooms, whose effects can persist for hours, a DMT trip might last only 5 to 15 minutes when the drug is inhaled or injected.
Though today DMT is commonly synthesized in the lab, and even studied as a potential treatment for depression, natural forms are found in a variety of plants, and have been taking our ancestors on mind-altering trips for thousands of years.
DMT on the brain
In a study published recently in the Proceedings of the National Academy of Sciences, Timmerman and a team of researchers described their efforts to see what this quintessentially human experience looks like in the brain as no research has revealed before. They recruited 20 healthy subjects who, on two different occasions, received either a highly potent, intravenous dose of DMT or a placebo while having their brains scanned with functional MRI and brain waves recorded through electroencephalography (EEG), the first time both technologies have been used in parallel while examining a tripping brain.
“This approach offers an important advancement because it enables the direct observation of changes in neuronal activity (EEG) in parallel with indirect changes seen through the fMRI blood oxygen level-dependent (BOLD) signal,” the researchers explained.
Timmerman and his colleagues were rewarded with some remarkable views of the DMT-altered brain. They witnessed its business-like hierarchical organization collapse, replaced with a state of global hyper-connectivity. Brain entropy, defined as “the number of neural states a given brain can access,” skyrocketed.
“The brain usually functions in this modular, organized, hierarchical way,” Timmermann explained in his Nautilus interview. “You have different networks and systems that crystallize as we grow older. What we see with DMT is that the systems that generate complex behaviors and tasks stop working in this specialized fashion. They start to work in synchrony with the rest of the brain.”
“We also see the major rhythms of the brain -- that serve a largely inhibitory, constraining function -- break down,” Timmerman’s co-author, Robin Carhart-Harris, a professor of neurology and psychiatry at the University of California-San Francisco, added when speaking to The Guardian.
Interestingly, some of the same patterns, though not to an identical degree, can be seen in the brains of experienced meditators as they meditate, in people with schizophrenia, and in infants, the researchers noted. This suggests that their brains may literally perceive the world differently.
Reality as a hallucination
It’s commonly said that our perception of reality is constructed by the brain. While many of us may intuitively acknowledge this as fact, it’s difficult to truly accept. According to Timmermann, DMT and psychedelics in general make the fabricated nature of reality abundantly clear to those who use them.
“They can experience how the world is a model we’re constructing in our brains. This is reality as a constrained hallucination.”
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