For most of human history, God, or the gods, were the source of authority for all knowledge. The only source of truth was scripture, and to question this was to question everything. Ever since the intellectual paradigm shift of the enlightenment, this has no longer been the case. The general view of science, and society at large, is that there is no longer any ultimate authority for knowledge. While the rejection of dogma may have freed us from the intellectual constraints of organised religion, it came at a steep price. What we gained in power and freedom, we lost in meaning. Our ancestors, for the most part, were not burdened with existential questions of purpose. Simply by virtue of their existence, God had deemed their life and all the actions it consisted of as meaningful. Today we do not share the same luxury. While most of us do not have to worry about collecting enough food to survive the next winter, we are instead haunted by the idea that maybe our lives and our struggles are meaningless. As Stephen Hawking said:

"The human race is just a chemical scum on a moderate-sized planet, orbiting around a very average star in the outer suburb of one among a hundred billion galaxies."

If this is indeed our reality it begs the questions: Can humans have any significance without God? Is there a way to recover meaning without an appeal to authority? Throughout this essay, I will attempt to answer these questions by looking at the work of two thinkers: Yuval Noah Harari and David Deutsch.

In his 2016 book, 'Homo Deus' Harari looks at this exact problem, giving an overview of the history of human meaning and how it was transformed by the enlightenment. In Harari's view, up until recently, the reason why this event did not lead to complete societal collapse was, in part, due to the rise of a new ideological framework underpinning our lives: Humanism. Instead of God being the source of all meaning and authority in our lives, Humanism eponymously designates that role to human beings and their experiences. Instead of a ruler's authority being backed up by divine decree, it is decided by voters in elections. Instead of beauty being that which embodies the truth of God, it rests in the eye of the beholder. This is such a fundamental part of our world today that we are almost blind to its ubiquity. The main thesis of Harari's book is that the core of humanist thought, and thus modern society, is under threat by science. He argues that as our understanding of the human mind and body grows, notions like 'free will' and an 'authentic self' are becoming less and less plausible. As such it can no longer be the intellectual bedrock it once was and an unwillingness to recognise this fact will sooner or later catch up with us. Harari proposes two solutions to this problem, both of which struck me as unsatisfactory replacements for a religious worldview.

The first of these is techno-humanism. Confronted with the threat of humans being made redundant by artificial intelligence, the techno-humanists suggest that instead of trying to fight the inevitable, we should merge with the algorithms, eventually abandoning our original bodies altogether and existing in what Harari refers to as the 'ocean of consciousness'. While this solution does allow us to maintain a significant role in our future, I believe it sidesteps his core criticisms of enlightenment ideals. We may be able to retain power, but we are simply kicking the humanist can down the road. A techno-humanist society is still predicated on the same core tenets that held up its predecessor and as such would still leave us just as lost for meaning. The second was Dataism. The fundamental idea of Dataism is that everything is either data or a data-processing algorithm and anything that allows for the additional collection or processing of data is good. As such, it is our moral obligation to create these systems and give them the data they need. Humanist ideals are completely rejected, along with our anthropocentric world view. The dataists see our lives are merely a means to a nobler end. While this does once again imbue humanity with purpose, it is a soulless solution, if one can even call it a solution at all. I fear to imagine the kind of atrocities we would commit under such a guiding principle.

If neither of these is a satisfactory solution to our initial question, maybe we are left to agree with Professor Hawking. What if there is nothing significant or meaningful about our lives. Are we merely a conscious smudge on an otherwise cold and indifferent universe? These were the thoughts that I was left with upon the completion of Homo Deus, the problem seemed irreconcilable. However, it was only much later that I realised that we are only doomed to a fatalistic attitude if we accept Harari's initial proposition: that the authority human experience was the core breakthrough of the enlightenment. In reality, this is just another appeal to authority, a sleight of hand switching out one dogma for another. In his 2011 book 'The beginning of infinity' David Deutsch makes an alternate proposition, that it is not ideas as unsound as 'free will' and an 'authentic self' that gives human beings significance, but our ability to create explanatory knowledge.

The creation of knowledge is not a process that is unique to humans but that does not mean it is common. The only other process we know that has this property is biological evolution. How exactly does evolution create knowledge? This becomes much clearer to us on closer inspection. Selective pressure decides which genes most successfully propagate through a given environment. The most successful ones must therefore, at least more so than the unsuccessful ones, aid their host organism's survival. This would include fight or flight instincts, which food is ok to eat, where to find prey, etc. If one were a sufficiently knowledgeable evolutionary biologist, they would be able to determine, from an animal's genes, features of the environment they evolved in (more accurately just those features that would exert selective pressure). Therefore, we can say that knowledge must be encoded in genes. This, however, does not rob humans of their unique significance. While humans' thoughts may not be the only knowledge-creating process, they are the only process that can create explanatory knowledge as opposed to merely predictive knowledge.

The knowledge generated by evolution is inherently bounded and parochial, rarely giving an organism much advantage outside of the niche that they evolved to fit, or small deviations from it. A bird that learnt to fly on one island would be able to fly perfectly fine on any other, but as soon as they go more than a few dozen miles up, the air becomes too thin for this knowledge to be used. Even further up than this and they are no longer able to survive at all. Explanatory knowledge is not subject to this limitation. Einstein developed his theory of general relativity by only utilising the evidence of his immediate experience, in combination with previous ideas developed by a similar method. Despite the narrow range of the inputs that helped him develop it, general relativity allows us to understand the behaviour of objects on the other side of the universe. While predictive knowledge only allows us to account for the myopic circumstances of its creation, the reach of a sufficiently deep explanation is potentially the entire universe (or multiverse).

The reach of explanatory knowledge does not just extend to everything that exists, but also everything that could exist. Every physical transformation can be put into one of two categories:

1. Impossible, because it is forbidden by the laws of nature
2. Achievable, given the right knowledge

There exists no third alternative. While this may seem obvious at first glance, the implications of this are profound. Given sufficient knowledge, human beings, and only human beings can do anything that is not forbidden by the laws of nature. This idea becomes even more staggering when we consider the full significance of knowledge.

It may seem as if, outside of our small corner of reality, the behaviour of most of the universe can be explained without any mention of people or knowledge at all. However, this assumption is an error. It has been theorised that if any intelligent beings wished to massively increase the energy available to them, the first logical progression for them would be the construction of what is known as a 'Dyson sphere', a swarm of solar panels built around their local star. This would allow them to harvest orders of magnitude more energy than the sliver that reaches the surface of their home planet. The anomalous data produced by this structure would be detectable to other lifeforms aiming their instruments at that star, and as such, has been proposed by astrophysicists as how we might first detect extra-terrestrial intelligent life. A scientific worldview that could fully account for all the observable phenomena in the night sky might have to consider this idea. Assuming that this would be intelligent life's preferred method of energy production may be underestimating our own ignorance, but if we instead assume some other method, or even that no intelligent life exists outside of earth, those views are still taking some position on the existence of beings near that star, their knowledge, and their goals. To fully understand the behaviour of the universe, we need to take knowledge-creating beings and the phenomena they can create into account, either by their presence or absence. A description of the universe is as fundamentally incomplete without a theory of knowledge as it is without a theory of gravity, or electromagnetism.

While people may be able to affect the universe, it is only logical to presume that the possible size of their impact must be negligibly small compared to say a supernova or a black hole. However, this could not be further from the truth. Consider a lump of iron, or a block of wood or any other physical object and then consider all the possible transformations that it can undergo: being melted down in the earth's core, burn to a crisp in a supernova, used to assemble a clock, etc. If we extended this exercise for all objects and all transformations, we would see that that class of transformations that can happen spontaneously — in the absence of knowledge — is negligibly small compared to those that cannot. In other words, almost all physically possible phenomena require a being with knowledge to instantiate them. If we resist our biological tendency to assume that only physical properties like mass and speed can measure significance, our place in the universe seems much grander. The presence of even a single human being suddenly allows for a reality with a level of richness and complexity incomparably larger than one without. If nothing else this fact alone demonstrates that our existence is far from inconsequential to the rest of the universe.

Despite all this, one might argue that while the possible significance of humans is large, we are still just mindless animals driven by a set of biological urges. That we are simple creatures and can be understood with perhaps not self-evident, but simple rules. However, as we will soon see, simply because we seek knowledge, this is another error. Take an astrophysicist working at any lab in any country. Every day, there is the possibility that some anomalous reading will come up on their screen that is a communication from intelligent lifeforms on the other side of the galaxy. If this reading can be verified and other possibilities ruled out, the discovery that we are not alone in the universe would lead the scientific community, and the rest of the world, to exhibit a set of behaviours radically different to the set in a reality where the signal had not been received. We can extend this line of reasoning to all fields of science, looking for truths both big and small. Just as beings with explanatory knowledge exert an influence on all reality, all reality, in turn, exerts an influence on beings that can understand that knowledge. To understand, and consequently predict, the sum total of human behaviour, knowledge of merely the inner workings of our bodies and minds is not sufficient. Simple biological reductionism is not enough: to understand human beings, you need to understand all of reality.

An appeal to authority, whether in the form of a divine being, or an authentic self is not the only means by which we can accept the benefits of science and still believe our lives and actions hold weight. The ability to create explanatory knowledge is unique to us, and as such, stored within our minds, are potentialities of cosmic significance. By whatever means the capacities of reason and consciousness have been endowed to us is irrelevant. What is relevant is the fact that we do possess them. This fact transforms us from a chance arrangement of atoms to the sole feature of reality capable of creatio ex nihilo. So, in opposition to Hawking's claim, we are not just 'chemical scum' whose fate is a matter of indifference to the rest of reality. It would not be inconceivable to say that, in light of this new evidence, humans are perhaps the most significant [^1] phenomenon in the universe.

[^1]: I have somewhat carelessly conflated significance and meaning throughout this essay. While significance does not necessarily imply meaning, I have assumed that it is a necessary (but not sufficient) condition for it. Claiming our lives to be meaningful is something above my pay grade, but I hope my arguments have at least ruled out the possibility that we are meaningless, which is a step in the right direction.