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We usually imagine reality as a chain of events: A causes B, which then causes C. Causes come first and effects follow. At the quantum level, however, this order may not always be fixed.

Experiments involving the **quantum switch** suggest that two processes can occur in an indefinite causal order. Instead of either A causing B or B causing A, a quantum system can behave as though both possibilities are present simultaneously.

This does not mean that causality disappears from everyday life. Dropped plates still fall, fire still burns, and actions still have consequences. But the familiar sequence of causes and effects may emerge only at the level of ordinary experience rather than describe the deepest structure of reality.

The question becomes especially important in attempts to combine quantum mechanics with gravity. In Einstein’s theory, gravity affects space and time. If matter can exist in a superposition of different states, the structure of spacetime—and therefore the order of events—may also become indefinite.

Physicists are now developing ways of describing reality without assuming a fixed causal order. Such theories remain incomplete, but they challenge one of our most basic intuitions: that the universe must always know which event happened first.

Perhaps cause and effect are not the foundation of reality.

Perhaps they are simply how reality appears to creatures like us.

**Sources:**

Natalie Wolchover, [“Quantum Mischief Rewrites the Laws of Cause and Effect”](https://www.quantamagazine.org/quantum-mischief-rewrites-the-laws-of-cause-and-effect-20210311/), *Quanta Magazine*, 11 March 2021.

The sequence of causes and effects doesn’t capture the fundamental nature of things

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# Homo Sapiens 2.0—or GMO Homo Sapiens?

After four billion years of evolution by one set of rules, our species may be about to begin evolving by another.

Advances in genetics, artificial intelligence and data analysis are giving us tools that could one day alter the genetic makeup of future children. These technologies may help eliminate inherited diseases, cure cancers and allow people to live longer and healthier lives.

The same tools, however, could also be used to select or modify characteristics unrelated to disease. Embryo selection and gene editing may eventually influence physical features, intelligence and other human traits.

Metzl does not argue that this genetic revolution should be stopped. He believes that humanity will embrace technologies capable of preventing disease and reducing suffering. But he also warns that genetic enhancement could create deep divisions, encourage new forms of eugenics, reduce genetic diversity and even contribute to conflicts within and between countries.

The genetic era has already begun. The question is not simply whether these technologies will be used, but how they will be used and who will participate in making those decisions.

Because the consequences may alter the evolutionary direction of our entire species, Metzl calls for a global conversation about the future of human genetic enhancement.

A thought of my own: perhaps one day genetic technologies could also help reduce the human tendency towards aggression. Aggression is shaped by many biological, psychological and social factors, so it is unlikely that we will find one gene responsible for it. Yet if we ever learn how to limit its most destructive forms, this could be one of the greatest benefits of genetic research. Human aggression has been one of our species’ most serious problems for at least the last several thousand years.

**Source:**

Jamie Metzl, [“Homo Sapiens 2.0? We Need a Species-Wide Conversation About the Future of Human Genetic Enhancement”](https://techcrunch.com/2016/05/01/homo-sapiens-2-0-we-need-a-species-wide-conversation-about-the-future-of-human-genetic-enhancement/), *TechCrunch*, 1 May 2016.

Homo Sapiens 2.0 or actually GMO Homo Sapiens.

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Certainty feels like strength. In science, however, it can become a weakness.

Science does not ask us to defend an idea forever. It asks whether the idea survives observation, criticism and attempts to prove it wrong. A scientific explanation is valuable not because an important person believes it, but because other people can examine the evidence independently.

This makes changing your mind a feature of science, not an admission of defeat. Carl Sagan observed that scientists sometimes respond to a convincing argument by acknowledging that their position was mistaken. It may be uncomfortable, but replacing an inadequate explanation with a better one means that science has worked exactly as intended.

The more surprising lesson is that skepticism alone is not enough. Someone who rejects every unfamiliar idea is not necessarily more rational than someone who believes everything. One refuses possible discoveries; the other cannot distinguish discovery from nonsense. Sagan argued for a balance between openness and rigorous examination:

> “It’s okay to reserve judgment until the evidence is in.”
>

This is harder than choosing a side immediately. Saying “I don’t know yet” provides none of the emotional satisfaction of certainty. It does, however, protect us from turning first impressions, authority or personal preference into facts.

Science remains reliable precisely because it does not claim to be infallible. Its conclusions are provisional: strong enough to use when supported by evidence, but always open to correction. An unanswered question is not an embarrassment that must be concealed with speculation. It is simply a place where investigation can begin.

The scientific habit is therefore not believing nothing. It is giving every claim only as much confidence as the available evidence deserves.

[Source: Carl Sagan — “The Burden of Skepticism”, *Skeptical Inquirer*](https://skepticalinquirer.org/1987/10/the-burden-of-skepticism/)

— Carl Sagan

SCIENCE