IT ISN’T easy to predict where the next leap in scientific understanding will come from. Indeed, ideas that, in hindsight, mark obvious paradigm shifts can first make you feel quite unsteady on your intellectual feet. So, as scientists poke around for new ways to understand the universe, how seriously should we take these embryonic revolutions?
In this week’s cover feature (see “How to wrap your head around the most mind-bending theories of reality”), philosopher Eric Schwitzgebel provides a handy guide to “weighing competing implausibilities”. Much of his advice boils down to whether you prioritise conceptual simplicity over adherence to empiricism.
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Take supersymmetry, the much-beloved (by physicists, at least) notion that every fundamental particle we know of has a much heavier partner that we are yet to discover. Its mathematical elegance sends proponents into rapture, but it is let down by the small matter of us not having a shred of evidence it is true.
Dark matter at first appears on firmer ground. Under our current best understanding of gravity, Albert Einstein’s general theory of relativity, various lines of evidence point us towards the idea that 85 per cent of the mass within the universe is invisible. We see its gravitational effects throughout the cosmos. And yet, dark matter feels a bit too convenient. Yes, it explains a bunch of otherwise unexplainable phenomena, but given that we are yet to directly detect a particle of dark matter, that explanation feels uncomfortably like writing “here be dragons” in the margins of cosmology.
That is why alternative approaches must be welcomed and judged on their relative merits, no matter how outlandish they may seem. As we report on page 10, a “post-quantum” theory of gravity is making waves by revisiting Einstein’s assumptions about the nature of space and time. Crucially, it can explain a key observation without needing to invoke the existence of dark matter. Much work is needed, but judged using Schwitzgebel’s tools, you may find this development is worth taking seriously, even if the current paradigm stands firm for now.
