From the perspective of the west, it all started in ancient Greece, around 600 BCE. This is during the Axial Age, a somewhat controversial term coined by the German philosopher Karl Jaspers to denote the remarkable intellectual and spiritual awakening that took place in various places around the world, roughly within the span of a century. Apart from the Greek explosion of thought, this is the time of Siddhartha Gautama (also known as the Buddha) in India, of Confucius and Lao Tzu in China, of Zoroaster (or Zoroaster) in ancient Persia – religious leaders and thinkers who would reformulate meaning of faith and morality. In Greece, Thales of Miletus and Pythagoras of Samos pioneered pre-Socratic philosophy, shifting (more or less) the focus of exploration and explanation from the divine to the natural.
To be sure, the divine never quite left early Greek thought, but with the beginnings of philosophy, trying to understand the workings of nature through logical reasoning — as opposed to supernatural reasoning — would become an option that did not exist before. The history of science, from its beginnings to the present, can be told as an increasingly successful split between belief in a supernatural component of reality and a strictly materialistic cosmos. The Enlightenment of the 17th and 18th centuries, the Age of Reason, literally means ‘to see the light’, the light here is clearly the superiority of human logic over any form of supernatural or nonscientific methodology to arrive at the ‘truth’ of things.
For example, Einstein was a believer who preached the basic reasonableness of nature; not weird inexplicable things, like a god playing dice – are ironic criticisms of the belief that the unpredictability of the quantum world was really fundamental to nature and not just a shortcoming of our current understanding.
To what extent we can understand the workings of nature only through logic is not something that science can answer. It is here that the complication begins. Through the diligent application of scientific methodology and the use of increasingly powerful tools, can the human mind attain a full understanding of the natural world? Is There an “End to Science”? This is the sensitive issue. If the split that began in pre-Socratic Greece were to be completed, nature as a whole would be amenable to a logical description, the full set of behaviors that scientific studies have identified, classified, and described by means of perpetual laws of nature. All scientists and engineers should be doing are practical applications of this knowledge, inventions and technologies that would meet our needs in different ways.
This kind of vision – or hope, really – goes all the way back to at least Plato, who in turn owes much of this expectation to Pythagoras and Parmenides, the philosopher of being. The dispute between the primacy of that which is timeless or unchangeable (Being), and that which is changeable and fluid (Becoming), is at least so old. Plato proposed that truth was in the immutable, rational world of Perfect Forms that preceded the troublesome and deceptive reality of the senses. For example the abstract form Chair embodies all chairs, objects that can take many forms in our sensory reality while serving their functionality (an object to sit on) and basic design (with a seat and some legs underneath). According to Plato, the forms hold the key to the essence of all things.
Plato used the allegory of the cave to explain that what humans see and experience is not true reality.
Credit: Gothika via Wikimedia Commons CC 4.0
When scientists and mathematicians use the term Platonic worldview, they generally mean it: the unbound ability of reason to unlock the secrets of creation one by one. For example, Einstein was a believer who preached the basic reasonableness of nature; not weird inexplicable things, like a god playing dice – are ironic criticisms of the belief that the unpredictability of the quantum world was really fundamental to nature and not just a shortcoming of our current understanding. Despite his strong belief in such an underlying order, Einstein acknowledged the imperfection of human knowledge: “What I see of nature is a beautiful structure that we can grasp only very imperfectly, and which a thoughtful person must fill with a sense of humility. ” (Quoted by Dukas and Hoffmann in Albert Einstein, The Human Side: Glimpses from His Archives (1979), 39.) Einstein embodies the tension between these two clashing worldviews, a tension that we still deeply care about today: on the one hand, the Platonic ideology that the fundamental matter of reality is logical and comprehensible to the human mind, and, on the other hand, the recognition that our reasoning has limitations, that our instruments have limitations and thus require some sort of definitive or complete understanding to reach the material world is nothing but an impossible, semi-religious dream.
This kind of tension is palpable today when we see groups of scientists passionately advocating for or against the existence of the multiverse, an idea that holds that our universe is one in many other universes; or for or against the final unification of the laws of nature.
Nature, of course, is always the last arbiter of any scientific dispute. Data somehow decides. That is the beauty and power that are at the heart of science. The challenge, however, is knowing when to let go of an idea. How long do you have to wait for an idea, tempting as it may be, to be considered unrealistic? This is where the debate gets interesting. Data to support more “out there” ideas, such as the multiverse or additional symmetries of nature required for association models, have been declined for decades, despite extensive searches with various tools and techniques. On the other hand, we only find when we look. So should we continue to defend these ideas? Who decides? Is it a community decision or should everyone follow their own way of thinking?
In 2019 I took part in an interesting live debate at the World Science Festival with physicists Michael Dine and Andrew Strominger and presented by physicist Brian Greene. The theme was string theory, our best candidate for an end theory of how matter particles interact with each other. When I got my PhD in 1986, it was with string theory the way. The only way. But by 2019, things had changed, and quite dramatically, due to the lack of supporting data. To my surprise, both Mike and Andy were very open to the fact that that certainty from the past was no longer there. String theory has taught physicists many things, and that may have been its point. The Platonic outlook was in jeopardy.
The dispute remains, although with any experiment that fails to provide supporting evidence for string theory, the dream becomes more difficult to justify. Will it be something of a generation, as celebrated physicist Max Planck once joked: “Ideas don’t die, physicists do”? (I’m paraphrasing.) I hope not. But it is a conversation that should be kept more out in the open, as was the case at the World Science Festival. Dreams die hard. But they may die a little more easily if we accept that our understanding of reality is limited and doesn’t always match our expectations of what should or shouldn’t be real.