Martin Rees’ Gifford lectures present an overview of the current scientific understanding of reality and the unique set of challenges that face the next generation of scientists and indeed the entire global community. As an astrophysicist, Rees brings to the discussion a cosmic perspective to the present human situation and asks his listeners to learn from this perspective on ‘deep time’. He concludes that the advances of science and technology in the last century have had considerable impact on our understanding of reality and our place in it. What is more, the science and technology from this century provide both incredible promise to the human project and incredible peril.
He begins with a sweeping account of the immensity of the universe contextualising the everyday experiences of the common person. He moves from the beginning with the Big Bang to various far future astronomical scenarios including the Big Crunch and infinite expansion. Rees gives an account of the development of celestial mechanics, the coalescence of basic chemistry and the fascinating field of quantum mechanics—from the very large to the very small. He explains that the problem to solve today in physics is the unification of both realms into a single ‘unified theory’ and important strides are being made in the area of string theory.
Rees claims we live in a fine-tuned universe. If any astrophysical constant strayed but a little from its present value then the complex environment needed to sustain life could never have been possible. This fine-tuning has him broach two subjects. First, it raises the possibility of intelligence elsewhere in the universe. Because our universe is ‘biophilic’ it is warranted to speculate whether there might be extra-terrestrial intelligences in other solar systems. Second, it invites thought on the reason for this fine-tuning. Whilst Rees recognises fine-tuning has been invoked as evidence for a Designer, he devotes his efforts towards the scientific theory of a multiverse explaining it is a valid, albeit conceptually speculative, scientific theory; not metaphysics.
However, Rees also cautions us in the coming century. Science and technology in the past two centuries have impacted our understanding of reality but they have also brought incredible risk. The nuclear armament race in the mid-20th century has escalated the possibility of significant global disaster and has ushered in a time where scientific and technological risks are growing. Today bioengineering can help prevent certain diseases but it can also be used for ‘bioterror’ with easily acquired chemicals. Rees calls upon scientists and the wider populace alike to meet these new challenges especially when new technologies are making it possible to even alter our fundamental human nature. Scientists are in a privileged position to help guide us through the coming years and ought to concern themselves with the application and ethical implications of their research. Still, it will take everyone working together to lead us into that far astrophysical future.