Artificial photosynthesis transforms CO₂ into liquefiable fuels

Yu and Jain. Plasmonic photosynthesis of C1–C3 hydrocarbons from carbon dioxide assisted by an ionic liquid. Nature Communications, May 2019.

Scientists have recently established a reliable “artificial photosynthesis” paradigm to produce fuels from water, carbon dioxide, and visible light. With the help of sunlight, chemical reactions between water and CO₂ are catalyzed in plants to generate and store solar energy in the form of glucose. This process is called photosynthesis. In the new study, the researchers developed an artificial process that uses the same mechanisms of natural photosynthesis to convert CO₂ and water into liquid fuel by using electron-rich gold nanoparticles as a catalyst. Gold nanoparticles function in the same role as chlorophyll in natural photosynthesis in the absorbing of light and transferring electrons and protons to catalyze the chemical reactions between CO₂ and water. They are known to be efficient at absorbing light and do not break down or degrade like other metals. The energy stored in the bonds of the hydrocarbon fuel can be freed by the conventional method of combustion or by new-generation, environmentally-friendly power fuel cells, thus producing electrical current. By converting CO₂ into more complex molecules like propane, green-energy technology is now one step closer to using excess CO₂ to store solar energy for use when the sun is not shining and in times of peak demand. While the development of this CO₂-to-liquid fuel may be exciting for proponents of green-energy technology, the artificial photosynthesis process is nowhere near as efficient as it is in plants. New methods should be developed to increase the efficiency of the catalysts and downstream chemical reactions at much higher scales.

Brain area that watches for walls identified

Henriksson et al. Rapid Invariant Encoding of Scene Layout in Human OPA. Neuron, May 2019.

Neuroscientists have identified the part of the human brain whose duty is to help us perceive the barriers which define the navigable space around us, such as walls or ceilings, so that so we can avoid bumping into things and navigate safely through our environment. By way of vision we have an almost instant sense of where we are in space. Although this process feels effortless, it requires the coordinated activity of multiple brain regions and neurons working together to give us this sense of our surroundings. This process has remained unknown. But thanks to a new study, we are a step closer to solving the puzzle. Using cutting-edge brain-imaging technologies, researchers examined the mental responses of volunteers as they were shown images of various three-dimensional scenes. The images depicted a typical room with three walls, a ceiling, and a floor, but then were abruptly changed by the removal of a wall or a ceiling. By doing this repeatedly, the team could pinpoint how the participant’s brain encoded every scene. In the brain scans of the volunteers, one brain area called the occipital place area (OPA) clearly stood out. OPA activity represented the geometry of the scenes and activity patterns, reflected the presence or absence of each component, such as a ceiling or a wall, and projected a detailed picture of the overall configuration. Interestingly, OPA seemed to ignore the surface appearance of the various components such as colors or textures in order to focus only on the geometric patterns. The OPA managed to perform all the necessary computations needed to get a sense of a room’s layout extremely fast – in just 100 milliseconds. In the future, the research team plans to incorporate virtual reality technology to create more realistic 3D environments for participants to experience, hopefully achieving much deeper insights into how our brains process and makes sense of the visual information.

Gut segments are organized by function

Esterházy D. et al. Compartmentalized gut lymph node drainage dictates adaptive immune responses. Nature, April 2019.

As food enters our intestine, it goes through a windy and lengthy journey. A new study provides new insights into how our intestines maximize nutrient uptake while protecting the body from potentially dangerous invading microbes. At first glance, the intestines appear to have a uniform tissue structure. But when scientists looked at them closer, they found that our food-processing canal seems to consist of multiple compartments that pace the immune system’s reactions to the food passing through. Scientists uncovered these functional intestine segments in mice when they examined the intestinal structures called gut draining lymph nodes, which orchestrate immune responses. The researchers found that nodes in different parts of the intestines had different cell composition, and they saw different immune responses between segments when they challenged the mice with a pathogen. They observed less aggressive defenses in the first segments where nutrients are absorbed, and more forceful responses at the end, where pathogens are eliminated. Researchers plan to exploit these immunological differences between the gut segments for treating gastrointestinal disorders. For example, by targeting immune-suppressing drugs to the specific gut segment where they’ll have the most effect, it might be possible to dampen their side-effects. The spectrum of immune responses along the intestines could also be used to make new and better oral vaccines. Thus far, scientists’ efforts to design oral vaccines have been hampered by the difficulty of generating a robust immune response; it is possible that the muted immune response at the beginning of the intestines might be part of the reason why oral vaccines tend to be less effective than injections. Thus, targeting the distant end of the intestine might be much more efficient way of inducing the immune response required.

Indeed, attaching a purpose to everything non-systematically is subjective and seems not to be compatible with the current scientific methodology. For this reason, some people tend to deny religious sources of knowledge, whereas other people tend to accept a dualist viewpoint where they separate the domains of religion and science. Such dualism pushes religion out of people’s lives and restrains it only to particular instances and environments, reframing religion with surrealist subjects.

The path to reviving religious spirituality in daily life, on the same objective domain with science, requires many approaches. One of them is to answer the following question: is it possible to find a systematic way of understanding the purpose of the phenomena that has been observed and discovered by scientific methodology?

Although scientific methodology has evolved throughout history, the common motive that fits all stages is exploring the causal relationship among phenomena and expressing causality with some set of laws and principles. If we traced back to the origins of the scientific approach, we would encounter Aristotle’s definitions. He stated in his book “Metaphysics” that there are four types of causes (Fine, G., 1987):

1. Material cause – i.e. the materials that something is composed of. For example, water, sunshine, soil etc. are necessary to plant a tree. Therefore, these are material causes for the tree that was planted.
2. Formal cause – in his original words, “the form or pattern; that is, the essential formula and the classes which contain it.” For instance, a drug can only be useful if its constituent chemicals are mixed in a certain ratio. Hence the specific ratio is the formal cause of the drug.
3. Efficient (or motive) cause – the prior conditions that lead to the resulting situation. This is what is usually considered as “the cause” in science, especially in physics. An example is the source of new cells, which was unknown until the 19^th century. It was François Raspail (1794–1878) who first stated Omnis cellula e cellula, meaning that every cell is derived from another cell which tells the efficient cause of cell (re)production. (http://www.ohio.edu/chastain/rz/raspail.htm)
4. Final cause – i.e. the purpose or the goal of something. This is also known as telos. In our daily language, we often mean the final cause or telos, when we talk about “whys.” For example, the telos for a seed to germinate is to become a tree.

Considering these different types of causes, which all together become a complete explanation, we can see that the current understanding of science is diverged from this point. These four categories of cause survived in science until the 17^th century. But then, by constraining science on the matter and its motion, as Francis Bacon stated in his Advancement of Learning (1605), only the material and efficient causes are taken into account as the major two subjects of science (Bacon 1605). During those days, Spinoza and Descartes deliberately rejected the final (teleological) cause and claimed that the efficient causes are necessary and sufficient to explain the universe. Thence, Newtonian physics was developed on the basis of the efficient cause. For example, the cause of acceleration is thought of as the force, in a sense that when a force F is applied to a mass m, the acceleration becomes a = F/m.

Causality in science is therefore reduced to the “efficient cause” and effect relationship. However, as we discussed, religions emphasize the purpose of events and accept God as the cause of causes. Therefore, religions use a different language, especially by underlining the telos, in terms of explaining phenomena. For instance, one of the amazing properties of water is that its least absorbing spectrum corresponds to the optical regime (Gedik, N. 2005). To explain this phenomenon, science asserts the efficient cause and searches for the relationship between the absorption spectrum and the natural oscillation frequency of the water molecule. However, disregarding the temporal order, this purpose-based approach says that because it is crucial and vital for living beings to receive sufficient light, and since the atmosphere largely consists of H₂O molecules, then water had to be transparent to the optical frequencies of light to allow creatures that have eyes and photosynthesis systems to get enough light.[1]

We should admit that the latter explanation does not sound strong enough to be generalized and be formulated. Therefore, we usually avoid using the adjective “scientific” for such explanations. But when our subjects or phenomena are chosen in the bio-world, we observe that the “standard” efficient causality does not give a satisfactory explanation, and the teleological causality is necessary. For example, the adaptation concept is teleological, which makes the usage of “final cause” indispensable in biology. Furthermore, in the early 19^th century, in his book The Origin of the Species, Charles Darwin deliberately employed the term “final cause,” as it was noticed by James Lennox (Lennox 1993). Although some people claim the opposite, by carefully investigating Darwin’s works, Asa Gray and James Lennox appreciate Darwin by stating that he is the first scientist who reconciled morphology and teleology. Simply put, every species are equipped with specialized organs so that they can maximally benefit from, or maximally defend against, their environment. The same idea is also valid from the religious point of view and does not necessarily deny natural selection.

We can find more examples of teleological causality in systems biology, which studies biological concepts in a holistic way and therefore utilizes a teleological language. For instance, during mitotic cell division, chromosomes are replicated only once and then separated into two new cells. But note that something, indeed a checkpoint, prevents the cell from replicating its DNA more than once. This situation appeals for attention and can be explained in two ways. First is the teleological, or what biologists sometimes call the “biological explanation.” DNA is replicated once because otherwise it is severely defective or even lethal for the cells. Such a teleological explanation is perfectly compatible with the mechanistic explanation (efficient cause) based on the chemical interactions of some related proteins, which can be modeled by thermodynamic equations. As the system is complex, it is often hard to fully fit into a model using thermodynamic formulations. However, system biology offers another way that mixes the language of teleological and efficient causes by considering the system as a signaling network, on which the signal (or information, as in the information theory) is carried out via specific protein phosphorylations or reactions. If we were to analyze the spectrum of the words used in systems biology, such as commitment, robustness, checkpoint, decision etc., we would see that its language is more similar to our purpose-based daily language. For such irreducibly complex systems, the employment of teleological concepts does not arise as metaphorical; rather, it is indispensable as the whole cannot be purely explained by its parts.

Other sciences also provide teleological examples. Beginning in the early 20^th century, quantum physics emerged, bringing along some very unintuitive experiments. For example, Einstein, Podolsky, and Rosen offered a paradox called EPR. This states that measurements on two spatially separate but entangled particles can demonstrate correlations that cannot be simply explained by efficient causes. Later on, this phenomenon, called quantum entanglement, was empirically validated and can be explained by the final causes, introducing a retrocausal relationship.

Theoretical physicist Ken Wharton argues that the process known as frustrated spontaneous emission is naturally explained by such teleological causality. A light-emitting atom stops emitting light when the surrounding atoms are no longer able to absorb light. The decision of the atom whether to decay or not depends on the other atoms’ absorption, which has not happened yet. The idea that “the atom is probing the future” is not only counter intuitive, but also difficult to accept on the basis of the efficient causality, as Wharton states. (G. Musser, 2014).

Although teleological explanations are not always indispensable and can always be accompanied by efficient causality, the urge for the simplest explanation usually brings teleological language to science. Because science has been facing complex systems in various fields, teleological (purpose based) causality has become necessary since the beginning of the 20^th century. As a purpose-orientated understanding of existence is fundamental for almost all religions, it would not be strange to observe the engagement of science and religion in the near future.

Returning back to the initial question, of whether the purpose-oriented view can be reconciled with scientific research, we see that this is already widely evident in the scientific community. But there are still some people who think religions oppose science, owing to their purpose-oriented view. The judgment is left to the reader.

Yusuf Malik holds a PhD in physics. He is a freelance writer based in Boston, USA.

Reference

1. Fine, G.. 1987. “Forms as Causes: Plato and Aristotle,” in A. Graeser (ed.), Mathematics and Metaphysics in Aristotle, Bern: Haupt, pp. 69–112.
2. http://www.ohio.edu/chastain/rz/raspail.htm
3. Bacon, Francis. 1605. “Of the Proficience and Advancement of Learning, Divine and Human.” en.wikisource.org.
4. Gedik, N. 2005. “The Miracles of Water,” The Fountain, Issue 49.
5. Lennox, James G. 1993. “Darwin Was a Teleologist.” Biology and Philosophy 8 (4).
6. George Musser. 2015. “The Quantum Mechanics of Fate,” Nautilus, February.

[1] The difference between this explanation and the anthropic principle may seem subtle here, but there is an enormous conceptual gap which extends beyond the scope of this article.