Scientific discoveries substantiate our awe when faced with the richness and universality of the laws of nature. But science falls short of explaining this natural order and why it exists in the first place.

This is where philosophy comes to the rescue. Science seeks to understand how the universe works, just as we might try to figure out the mechanics of a sophisticated engine. Philosophy, by contrast, addresses questions that transcend the functionality of nature, as we might pursue the complementary task of figuring out why the engine is constructed in a particular way.

As a scientist, I am surprised at the degree of organization the universe exhibits; the same laws that govern its earliest moments—something we know from observations of the most distant galaxies and most ancient radiation—also preside over what we find today in laboratories on Earth. This should not be taken for granted. We could have witnessed a fragmented reality, one in which different regions of spacetime obey different sets of laws or even behave chaotically with no rational explanation.

By studying the physical constituents of an engine, one acquires a better understanding of how it works but not necessarily the purpose for its existence. Metaphysical thinking can supplement science in territories not accessible to empirical inquiry. Within these domains, philosophy can build on scientific knowledge rather than yield to it.

But there are domains in which the two might be headed toward an irreconcilable conflict. Consider the notion of free will, which seems to play an indispensable role in guiding our actions. Science is founded on the premise nothing is better than knowing the truth. But in real life is it always best to be guided by the scientific truth? The answer might depend on circumstances. For example, even if medical science could forecast the time and cause of one’s death, it might be better for to go through life without knowing because this very knowledge might take away the will to live.

Could the same reasoning extend to scientific research? In particular, are we better off knowing whether or not free will exists? For now this question is moot because we do not have the means for answering the question. But it is conceivable that in the future we will find out it doesn’t. That could be one result of the development of self-learning machines equipped with artificial intelligence whose behavior could be shaped by modifying the details of their underlying algorithms, just as you can tune the power of an engine by artificially changing its constituents.

In case the emergent phenomenon of free will is reproduced artificially, would such knowledge tear apart the fabric of society? Without the notion of “free will” there would be neither ethical responsibility nor the fundamental freedom to shape the future through our decisions. Would human life lose its purpose? The realization our actions are a product of circumstances might shut down social consciousness and the engine of our most ambitious aspirations.

This would be a case where understanding an engine’s mechanics could automatically shut it off. It might trigger a loss of interest in making a difference, in contrast to a path where the illusion of “free will” could ultimately lead humans to modify the future on cosmic scales—from artificially creating megastructures on planets to spreading throughout the cosmos, or by devising nuclear power plants that would outlast the longest-lived stars. The conceptual damage from the loss of the belief in “free will” could be as devastating to human culture as the physical damage from a nuclear winter would be.

There is no doubt philosophy plays an essential role for society because scientific knowledge is inherently incomplete. For example, we know our documented history started at a point in time we call the big bang, but we do not have a clear sense of what was there before. Without knowing what happened before the big bang, our existential perspective is incomplete. Similarly, we have no clue as to whether we are alone in the universe. Knowing that fact would determine the significance we assign to human actions on the global stage.

Fortunately, we currently have the technology to search for both primitive and intelligent life elsewhere. And the knowledge we will acquire over the next millennium may shape the way we view our place in the universe in an unexpected fashion—whether we have “free will” or not.