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by
Brian Greene
Well beyond its utility in personal hygiene, water’s capacity to grab hold of and ingest substances is indispensable to life. Cell interiors are miniature chemistry labs whose workings require the rapid movement of a vast collection of ingredients: nutrients in, waste out, comingling of chemicals to synthesize substances required for cellular function, and so on. Water makes this possible.
“Water is life’s matter and matrix, mother and medium. There is no life without water. Life could leave the ocean when it learned to grow a skin, a bag in which to take the water with it. We are still living in water, having the water now inside.”21
The Unity of Life
The Unity of Life’s Information
The sheer number of ways that twenty distinct amino acids can be linked in a long chain makes this evident: for a chain with one hundred and fifty amino acids (a small protein), there are about 10195 different arrangements, far larger than the number of particles in the observable universe.
Impressive! Most impressive!
Watson and Crick.
And Franklin!
The Unity of Life’s Energy
And so the energy supporting all the actions of all living things can be traced to one and the same process, jumping electrons executing a series of cellular redox reactions.
It’s why Albert Szent-Györgyi, continuing his poetic reflections, mused, “Life is nothing but an electron looking for a place to rest.”
Biology and Batteries
Summary
Evolution Before Evolution
How did the genetic component of life—the capacity to store, utilize, and replicate information—come to be?
How did the metabolic component of life—the capacity to extract, store, and utilize chemical energy—come to be?
How did the packaging of genetic and metabolic molecular machinery into self-containe...
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Nature is not in a hurry and does not need to meet a bottom line. The cost of innovating by small random changes is a cost nature can bear.
Toward the Origins of Life
Consider the implication. Molecules of RNA, blending software and hardware, have the potential to sidestep the chicken and egg conundrum: How do you assemble molecular hardware without first having the molecular software, the instructions to carry out the assembling? How do you synthesize molecular software without first having the molecular hardware, the infrastructure to carry out the synthesizing?
The Physics of Information
Thermodynamics and Life
The nuclear force, in tandem with gravity, is a fount of life-giving low-entropy fuel.
A General Theory of Life?
What, then, is the path from life to consciousness?
5
PARTICLES AND CONSCIOUSNESS
From Life ...
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For science to pay no mind to consciousness would be to turn from the very thing, the only thing, we each can count on.
The challenge is that simplifications effective for one class of problems can be less so for others. Model the planets as solid balls and you can work out their trajectories with ease and precision. Model your head as a solid ball and the insights into the nature of mind will be less enlightening. But to jettison unproductive approximations and lay bare the inner workings of a system containing as many particles as the brain—a laudable goal—would require mastering a level of complexity fantastically beyond the reach of today’s most sophisticated mathematical and computational methods.
Consciousness and Storytelling
Can matter, on its own, produce the sensations infusing conscious awareness?
Can our conscious sense of autonomy be nothing more than the laws of physics acting themselves out on the matter constituting brain and body?
In the Shadows
The Hard Problem
How then does a whirl of particles inside a head—which is all that a brain is—create impressions, sensations, and feelings?
The challenge to envision such a solution for consciousness motivated Chalmers’s assessment. He argued that not only are we lacking a bridge from mindless particles to mindful experience, if we try to build one using a reductionist blueprint—making use of the particles and laws that constitute the fundamental basis of science as we know it—we will fail.
Something About Mary
The physicalist perspective does indeed summarize my own long-held view.
Here’s the question: From this first experience of the color red, will Mary learn anything new? By finally having the inner experience of color, will she acquire new understanding?
Philosopher Daniel Dennett asks us to really consider the implication of Mary’s exhaustive knowledge of the physical facts. His point is that the concept of complete physical understanding is so utterly foreign that we grossly underestimate the explanatory power it would provide. With such an all-encompassing grasp, from the physics of light to the biochemistry of eyes to the neuroscience of the brain, Dennett argues that Mary would be able to discern the inner sensation of red long before experiencing it.
A Tale of Two Tales
The evidence strongly favors the existing framework of physics, chemistry, and biology as being fully sufficient for explaining life. The hard problem of life, while surely difficult, has been reclassified as easy.
Many researchers envision that vitalism’s tale will be recapitulated with consciousness: as we gain an ever-deeper understanding of the brain, the hard problem of consciousness will slowly evaporate. Although currently mysterious, inner experience will gradually be seen as a direct consequence of the brain’s physiological activities. What we are missing is a full command of the brain’s inner workings, not a new variety of mind-stuff. One day, according to this physicalist perspective, folks will smile as they think back on how we once invested consciousness with such impassioned but
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Theories of Everything
Carl Sagan’s famous dictum that extraordinary claims require extraordinary evidence is an apt guide.
The Mind Integrates Information
Our charge, in his view, is not to explain how conscious experience emerges from whirring particles but rather to determine the conditions required for a system to have such experiences. And that’s what integrated information theory seeks to do.
The Mind Models the Mind
Red is a human construct that happens deep inside your head.
As with red, the only place the new car smell happens is within your brain.
Brains that survived are brains that avoided being consumed by details that lacked survival value. Replace the red Ferrari with a rumbling avalanche or a quaking earth, and you can see the survival advantage of having a quick and dirty mental representation that facilitates a rapid response.
