A growing group of experts thinks that we should abandon the assumption that present actions can’t affect past events in quantum physics, called ‘retrocausality.’ The future might influence the past.
In 2022, the physics Nobel prize was awarded for experimental work showing that the quantum world must break some of our fundamental intuitions about how the universe works.
Many look at those experiments and conclude that they challenge “locality” — the intuition that distant objects need a physical mediator to interact. And indeed, a mysterious connection between distant particles would be one way to explain these experimental results.
Others instead think the experiments challenge “realism” — the intuition that there’s an objective state of affairs underlying our experience. After all, the experiments are only difficult to explain if our measurements are thought to correspond to something real. Either way, many physicists agree about what’s been called “the death by experiment” of local realism.
But what if both of these intuitions can be saved, at the expense of a third? A growing group of experts think that we should abandon instead the assumption that present actions can’t affect past events. Called “retrocausality,” this option claims to rescue both locality and realism.
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What is causation anyway? Let’s start with the line everyone knows: correlation is not causation. Some correlations are causation, but not all. What’s the difference?
Consider two examples. (1) There’s a correlation between a barometer needle and the weather – that’s why we learn about the weather by looking at the barometer. But no one thinks that the barometer needle is causing the weather. (2) Drinking strong coffee is correlated with a raised heart rate. Here it seems right to say that the first is causing the second.
The difference is that if we “wiggle” the barometer needle, we won’t change the weather. The weather and the barometer needle are both controlled by a third thing, the atmospheric pressure – that’s why they are correlated. When we control the needle ourselves, we break the link to the air pressure, and the correlation goes away.
But if we intervene to change someone’s coffee consumption, we’ll usually change their heart rate, too. Causal correlations are those that still hold when we wiggle one of the variables.
A new study led by Yale University and the Broad Institute of MIT and Harvard has discovered that information ‘deleted’ from the human genome may be what made us human.