Astrophysics: A Philosophical Perspective

The following post is less than traditional. I wanted to write on something that is very dear to my heart, something that I feel is rather underrepresented in the astrophysical community. It is a reflection on the connections between astrophysics and philosophy. As such there are no definitive conclusions. This post is meant to be thought-provoking and raise more questions than it answers. After all, sometimes, the answer is in the question itself.

I believe in a law. It is a law that I have experienced only when I stare in awe and wonder into the vast starry sky above me. Each point of light represents another sun located 10 – 100,000 light-years away. If I probe deeper with a telescope I can observe individual galaxies against the backdrop of the vacuum of space. I understand, as I look into the cosmos, that the light has traveled billions of years before reaching my eyes; I realize that I am looking deep into the history of space and time itself. I constantly return to an image of the furthest object observed: a galaxy whose light was emitted fewer than 500 million years after the Big Bang. At this early stage in its history, the Universe was much smaller and only a few galaxies and stars had formed.  It is in these first stars that the elements needed to sustain human life were created. Staring into the night sky is a meditation on time, space, and the origin of humanity itself. It is with a much greater understanding of the Universe that I live my life in a new manner. The night sky has always compelled me to act.

                                                             The most distant galaxy observed in the Hubble Ultra Deep Field.                                                                       Credit:

This duty calls me into the realms of philosophy and astrophysics. My academic career has thus been composed of balancing two identities.  But with every passing moment I come to find that the two forces are not opposing at all. As I understand the connections and correlations between the two disciplines, I am drawn toward an ever-expanding duality. Astrophysics and philosophy are not opposing entities, represented by a thesis and antithesis, but rather a synthesis. Their common truths can be reconciled to form a greater and more profound thesis. Kant explained that “two things fill the mind with ever increasing admiration and awe, the more often and steadily we reflect upon them: the starry heavens above me and the moral law within me”[1]. I have found that this increasing admiration compels me to study both the starry heavens and the moral law within me. The two separate entities have important points of contact. The starry heavens compel me to act according to the moral law, as the moral law drives a further scientific understanding.

It is the idea of a law that drives scientific discovery forward. Physics is the study of the basic structures of and processes of change in matter and energy dictated by physical laws. But with the birth of quantum mechanics we have found that certain laws can no longer be taken as true on every scale. For example, light has wave-particle duality. When transmitted though a slit, light clearly shows wave-like interference patterns. Conversely Einstein’s equation for the photoelectric effect and Compton’s work on photon scattering, show that light travels much like a stream of particles. Light is thus both a stream of particles and a set of waves.  We view one or the other depending on the method we use to observe. Similarly Heisenberg’s uncertainty principle demonstrates that the more precise one’s measurement of an electron’s energy, the more uncertain is the measurement of its lifetime. It is even possible that if one were to continuously observe a certain particle, it would never decay (the quantum zeno effect). Thus we have to choose between wave or particle models and between accurate measurements of energy or time. We now have to consider the interaction between object and observer in every experiment. We can no longer draw a sharp line between the two. Science now depends on subjective agreement between observers. It is no longer a simple set of laws independent of the observer.

The subjectivity of physics is further identified with Einstein’s theory of Special Relativity. Einstein put forward two postulates: the constancy of the speed of light and the principle that all laws of physics must be exactly the same for all observers in relative motion. Here we find that only the speed of light is invariable. Everything, including space and time, is ultimately relative. When an object moves close to the speed of light its length appears to contract. When a particle moves close to the speed of light, time dilates such that the lifetime of the particle seems much longer. Space and time are not separate but are united in a space-time continuum. There is an interplay between temporal processes and spatial geometry. This shows a dynamic and interconnected Universe.  Space and time, the observed and the observer, and energy and time are all inseparable.

The evolution of the Universe over 13.7 billion years. Credit:

This new conceptual understanding of the world compels me to act accordingly. Quantum physics and special relativity point to a unity and an interconnectedness of events. Light is both a collection of particles and a wave. Particles are patterns of vibration that are continually being created and destroyed. Matter appears as energy and vice versa. We can no longer differentiate between space and time. Astrophysics shows us a dynamic world with a long history of change and development. It is impermanent and in ceaseless motion. Similarly, it is not dictated by easily observable laws. This leads to a philosophical view where life is transitory.  As the pre-Socratic philosopher, Heraclitus put forth, the Universe is in a state of permanent flux and reality is merely a succession of transitory states.  Standing under the vast starry sky we can experience wonder and awe in a way we never did before. Now we can imagine that the cosmos has included stretches of space and time that we can hardly imagine. The Copernican Principle explains that the Earth is not in a privileged location in space. It is a lesson on humility. This meditation on space and time compels me to act. There is thus an intimate connection between one’s scientific understanding of the world, and the ethical values that guide one’s behavior.

There is a crucial paradox found within the study of astrophysics. While the study of quantum physics and special relativity teach humility in an unimaginable Universe, it also shows our unique place within such a dynamic existence. It is within the cores of the first generation of massive stars that the elements needed to sustain human life were created through the process of fusion. We now understand that the possibility of life depends on the value of a few physical constants, and had their value differed by a miniscule amount life would have been impossible. It depends on the expansion rate of the Universe, the formation of the elements, the particle/antiparticle ratio, and other physical laws determined throughout cosmology. Stephen Hawking stated that “if the rate of expansion one second after the Big Bang had been smaller by even one part in a hundred thousand million million, the Universe would have recollapsed before it even reached its present size”[2]. The Anthropic Principle highlights that observations of the Universe must be compatible with the observer.  In other words: the Universe has the necessary conditions needed to accommodate human life. While we may know little of our incredibly complex and dynamic Universe our very existence is simply remarkable.

The night sky is a meditation on space, time, and the origins of humanity itself. Modern physics demonstrates that all events are connected: the observer and the observed, energy and lifetime, and space and time. The Universe is impermanent and in ceaseless motion. The Copernican principle demonstrates that the earth is not at a preferred location within this dynamic Universe. Thus it is a lesson on humility. Yet the Anthropic Principle explains that our existence is in fact remarkable, in that it is statistically unreasonable. It is thus with a greater understanding of the Universe that I live my life. I am both humble and remarkably thankful to exist within such a wonderfully dynamic world that we can only begin to understand. With a universal outlook on life, I am constantly compelled to probe deeper into the various philosophical laws that govern the way in which I choose to act.


[1] Critique of Practical Reason, 5: 161-2

[2] A Brief History of Time

About Shannon Hall

While writing for astrobites I was a graduate student at the University of Wyoming working on exoplanet research. Previously, I graduated from Whitman College with two degrees: one in physics-astronomy and one in philosophy. I am now working toward my career goals in science journalism and education. Feel free to visit my website.


  1. One of the more wonderful posts for us non-scientists. Thanks.

  2. “the Universe has the necessary conditions needed to accommodate human life”,I don’t agree with the “accommodate”,because the observers have no choice.
    The Anthropic Principle is natural and it suggests nothing because we human may birth in randomness,it probably exist some cosmos without life and our existence just owe to luck.

  3. Shannon,
    Thank you for sharing this. I have been reading Will Durant lately and wonder what he would have to say if He where here to see the discoveries of late?
    Keep sharing.

  4. This is a great post. I’ve been having the same dilemma lately.

    So much to learn.

  5. I have saved your essay and shall print it out and read it at a later date when I have more time (currently I am at work on my lunch break). Kudos, nevertheless, on your recognition and promotion of disciplinary similarities, in both intent and method, between science and philosophy; a noble task indeed.



  1. Astrophysical philosophy | Youkraft - [...] Astrophysics: A Philosophical Perspective | astrobitesApr 1, 2012 … A reflection on the relationship between astrophysics and philosophy. [...]

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