The Biochemistry of Thought
While it is fascinating to view the generation of a thought through the lens of biochemistry, the icy, analytic world of science can leave us less than satisfied.
The peculiar nature of a thought, which begins with lush imagery that our mind spontaneously produces in picoseconds (a trillionth of a second), is truly a miraculous marvel. The science is intriguing, but it fails to bring us closer to grasping the nature of a thought.
With the advances of noninvasive probing technologies such as fMRI (functional magnetic resonance imaging) and EEG (electroencephalogram), scientists can identify the regions of the brain that generate mental images, the prototypes of our thoughts.
Scientists have uncovered a list of 100-plus biochemical compounds, the neurotransmitters, that transmit signals across chemical synapses, the bridges between neurons or between neurons and muscle and gland cells: glutamate, acetylcholine, dopamine, epinephrine (adrenaline), histamine, etc.
Therefore, we have a far clearer picture of the brain, with its roughly 85 billion neurons, each with some 15,000 connections to neighboring neurons. The pathway complexity is staggering, summarized in the “connectome,” a kind of wiring diagram mapping all neural connections in an organism.
But, we are inclined to ask, how does that translate into a thought or image that seems to materialize in the fraction of a second? One moment, we are sitting quietly looking out the window as a soft breeze sways the branches of a flowering tree, and the next, we are gifted with the thought of the hummingbird we saw yesterday, flitting from flower to flower, its wings an astonishing blur. The thought is a phantom entirely without substance, and it seems to float into our consciousness. The image is crisp, perfectly defined, and it is often laden with emotion, at times welcome, others not. So the science of thought takes our understanding just so far. Let’s delve into an entirely different universe of thought.
Hamlet’s Soliloquy
For a segue to a contrasting conception of thought, we turn to the famous soliloquy in Hamlet, which begins with one of the most-quoted lines in English: “To be, or not to be…”. In just thirty-three lines, Shakespeare describes the quintessential conundrum of human existence: whether to bear life’s burdens or, in the hope of a heavenly paradise, “To die: to sleep; No more.” Hamlet concludes that the menacing uncertainty, that is, “the dread of something after death,/ The undiscover’d country,” has such power over us that “…conscience does make cowards of us all.” His speech then captures the implications of his serial indecisions:
And thus the native hue of resolution
Is sicklied o’er with the pale cast of thought,
And enterprises of great pith and moment
With this regard their currents turn awry,
And lose the name of action.
The “native hue of resolution” is our innate will to act with a singular determination, such that we achieve our goal. As Shakespeare describes, in this context our normally intact resolve is subject to disease: it is “sicklied o’er with the pale cast of thought.” Here the very essence of “thought” is vitiated and rendered impotent, such that our grand plans—“enterprises”—are immobilized.
In this context, the bard ascribes to thought the agency normally associated with the kinetic action of a person: the creation of a thought, then decision, then the act. As the contaminated thought suspends Hamlet’s capacity to act, his mind is reeling, feverishly running scenarios for and against taking action. This is clearly not “…a consummation devoutly to be wished.”
William Blake’s Poem, The Fly
Little Fly,
Thy summer’s play
My thoughtless hand
Has brushed away.
Am not I
A fly like thee?
Or art not thou
A man like me?
For I dance
And drink, and sing,
Till some blind hand
Shall brush my wing.
If thought is life
And strength and breath
And the want
Of thought is death;
Then am I
A happy fly,
If I live,
Or if I die.
The Fly was published in 1794 as part of Blake’s Songs of Experience, and it provides a window into the nature of thought in his poetic universe. It begins with a subtle violence, the brushing away of a fly, thus terminating its life. That signals the speaker’s entry into a confrontation with himself, a kind of mirror: how precisely is the fly’s life connected to that of the speaker?
The first surprise is that unlike poets who draw comparisons between themselves and elevated beings, including God, Blake’s eye is cast downward, to the miniscule life of a fly. Note that the speaker doesn’t merely inform us that he killed the fly, he confesses in language that triggers the poem’s motif: the guilt is ascribed to his “thoughtless hand.” [Emphasis added.]
That transitions to the curious juxtaposition of the narrator and the fly in the second stanza, artfully suggesting their lives share vital attributes. Stanza three extends the identification into the future tense. The speaker dances and sings “Till some blind hand/ Shall brush my wing.” In this instance, “blind” replaces “thoughtless,” a substitution that has profound implications. Whereas the speaker’s hand in the first stanza was merely careless, the force that will end his own life is far more complex: its blindness suggests a baleful being from the spiritual world. We might even suggest that it is a legitimate form of lex talionis (“…an eye for an eye…”; Leviticus 24:17-22), something not inconsistent with Blake’s religious beliefs.
The speaker’s precarious fate recalls Gloucester’s plaintive cry, questioning whether there is justice in the universe, as he wanders on the heath after being blinded by Cornwall and Regan: “As flies to wanton boys are we to the gods; They kill us for their sport.” (King Lear, Act IV, Scene 1)
The fourth stanza explicitly defines the essence of thought: it is life, strength, and breath, and the absence of thought is death. We pause to observe that, in light of this definition, the speaker is implicitly guilty of not being fully alive since his act in stanza one was “thoughtless.” That is a level of moral self-indictment rare among poets.
The fifth stanza has puzzled critics for over two centuries, and given its nihilistic tone—Blake had well-defined religious views—it seems on first reading even more ironic. How can the absence of thought lead to a state of happiness?
The key to resolving this apparent paradox begins by recognizing that the speaker is now the fly incarnate. In this interpretation, we note that his comparison with the fly in stanza three does not include the uniquely human function of thought (i.e., only “dance, drink, and sing”). Therefore, in biological terms, the absence of thought is immaterial, because flies have no such capacity; ergo, the speaker—that is, the fly—would effectively be happy were he to live or die.
It is a distinct blessing that the same cannot be said of humans, who cherish thoughts as a blessed gift from Almighty God.
Philip E. Mella