This story is part of our Cosmic Perspective special, in which we confront the staggering vastness of the cosmos and our place in it. Read the rest of the series here.
Perfect it may not be, but science is our best route to objective knowledge. Through observation, experiment and mathematical abstraction, it strives for a third-person perspective, a view from the outside of whatever we investigate. That is perhaps most obvious in physics, which seeks to describe things at every scale. 鈥淲e take ourselves out of the system to stabilise [it] as an object that we can think about,鈥� says , a philosopher at Johns Hopkins University in Maryland.
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This separation of scientific understanding from subjective experience began in the 16th century, when Galileo Galilei showed it was possible to describe the movement of bodies on Earth and in the heavens according to mathematical laws. And you can鈥檛 say it hasn鈥檛 worked. Today, physicists can look proudly upon a vast tower of ideas and equations that closely predict how reality works at almost every level, from the grand narrative of the origins and evolution of the universe to the minutiae of the elementary particles that comprise it.
But in recent years, a growing number of physicists have come to realise that this notion of an objective universe, independent of our experience of it, is an illusion. 鈥淲e get so excited about our capacity to abstract and extrapolate that we forget that physical models are not reality,鈥� says cosmologist at Dartmouth College in New Hampshire.
That is a problem, he says. We fail to recognise that our subjective experience is part of the universe 鈥� that our models are the product of our insider鈥檚 perspective, rather than a faithful representation of reality 鈥� and this can lead us astray.
Why facts are relative in quantum theory
The flaws in assuming we can have a purely objective perspective are clearest when you consider quantum mechanics, the famously strange set of rules governing the behaviour of subatomic particles. Quantum theory says 鈥� and countless experiments have confirmed 鈥� that you can only know whether a particle will be here or there, say, when you measure it. Different experimenters carrying out the same single measurement will end up with different results.
鈥淨uantum theory is really screaming at us that observers matter, that facts are relative,鈥� says , a theorist at Ludwig-Maximilians University in Germany. 鈥淭he relationship between our minds, our models and the world鈥� it鈥檚 very subtle.鈥�
This calls into question the pursuit of a neat set of equations that describes the universe as a whole, known as a theory of everything. 鈥淟et鈥檚 call it an abuse of power,鈥� says Gleiser, whose recent book 鈥� co-authored with astrophysicist and philosopher 鈥� argues that physicists鈥� 鈥渉ubris鈥� about the meaning of mathematical laws is actually preventing us from understanding the true nature of the universe and our place within it. 鈥淲e must not forget that these tiny characters, we ourselves, are also the authors of the narrative,鈥� they write.
Oriti expresses a similar sentiment. 鈥淭rying to understand the mind of God is an outdated view of physics,鈥� he says. 鈥淲e can only know the universe from the inside.鈥�
The question is, how can we make sense of it from within, without discounting our role in it? For Oriti, it is about making sure that the ways we understand different aspects of the universe, coming from multiple observing perspectives, don鈥檛 contradict one another. 鈥淭he best we can hope for is that every [observer], with its own perspective, is capable of determining what is seen from all the other perspectives, by being able to translate between perspectives 鈥� and not have anything left untranslatable.鈥�
Perhaps there is no single 鈥榬eality鈥�
In practice, this means that perhaps we shouldn鈥檛 think in terms of a single, objective view of reality. Ortiti thinks of reality as intersubjective; it might lie in the information relating different perspectives to one another.
Similarly, Gleiser increasingly views the cosmos from the perspective of 鈥渟ystems thinking鈥�, which makes sense of the complexity of the world through the interconnections between parts. He is among those who suspect the key to that could be a better understanding of emergence, where properties that don鈥檛 seem to exist when we look at the individual components of a complex system suddenly take shape when we see it as a whole, even from the inside.
This new approach to cosmology would look very different to the status quo, says Gleiser, having more in common with the study of biospheres than black holes. 鈥淚t鈥檚 a different ball game,鈥� he says.
One thing, at least, has become clear. 鈥淚f you鈥檙e asking a question that demands an external view of the universe,鈥� says Ismael, 鈥渢hen you鈥檙e not asking a question that makes sense.鈥�
