Imagine a planet on the far side of the galaxy. We will never interact with it. We will never see it. What happens there is irrelevant to us, now and for the conceivable future. What would you hope this planet is like?

Would you hope that it’s a sterile rock, as barren as our Moon? Or would you hope it has life? I think, like me, you’ll hope it has life. Life has value. Other things being equal, a planet with life is better than a planet without. I won’t argue for this. I take it as a starting point, an assumption. I invite you to join me in feeling this way or at least to consider for the sake of argument what might follow from feeling this way. Life – even simple, nonconscious, microbial life – has some intrinsic value, value for its own sake. The Universe is richer for containing it.

What kind of life might we hope for on behalf of this distant planet, if we are, so to speak, benevolently imagining it into existence? Do we hope for only microbial life and nothing more complex, nothing multicellular? Or do we hope for complex life, with the alien analogue of lush rainforests and teeming coral reefs, rich ecosystems with ferns and moss and kelp, eels and ant hives, parakeets and spiders, squid and tumbleweeds and hermaphroditic snails and mushroom colonies joined at the root – or rather, not to duplicate Earth too closely, life forms as diverse and wondrous as these, but in a distinct alien style? Again, I think you will join me in hoping for diverse, thriving complexity.

Should we stop there, though? Don’t we also hope for (for lack of a better word) intelligent life – life capable of complex linguistic communication, art and science, decades-long cooperative projects, elaborate fantasies, love and war, heroic self-sacrifice and villainous treachery (it’s probably too much to expect one without the other), ecstasy and anguish, incredible athletic feats – life that possesses a knowledge of its history, hopes for the distant future, introspective self-criticism, the capacity to be struck with awe and wonder at the scale of the cosmos? I’m not asking you to imagine a distant paradise but instead only a realistic package, a planet with a fair mix of the inspiring and the horrifying.

Among the things I’d most hope for is a rich curiosity that can and sometimes does speculate ambitiously, pushing against the edges of its understanding – beings with an intellect that allows them to ask profoundly difficult questions about the origin of the Universe, the nature of value, the grounds of knowledge, the fundamental structure of reality, the nature and limits of its own mind. I would hope for a species, or two, or a hundred, whose enquiry isn’t limited to the immediate, the practical or the straightforwardly answerable, that can wonder ‘Why?’ even with no foreseeable method to achieve an answer. An intelligent species with no such speculative impulse would swim only in the shallows. Even if it had love, joy, artwork, athletic competitions and soaring architecture, it would think only instrumentally.

Let’s turn our eyes back to Earth. A significant part of what makes Earth a bright spot of value in the cosmos – perhaps the brightest spot in our galaxy – is that certain skin-bags of mostly water can gaze up at the stars and speculate. We can think about the beginning before the beginning; we can wonder why there is something rather than nothing; we can tie ourselves in knots about the origins of value and the significance of art; we can worry about preposterous-seeming forms of radical scepticism; we can concoct six competing theories of why two and two is (or isn’t always) four. We possess depths – a capacity to query far beyond the here and now, far beyond the practical and visible, toward questions stupendously abstract, general and daunting. To any bluebirds or kangaroos who might be listening, I say, amazing as you are, you really have no idea how much more amazing a species could be.

Earth is a bright spot of value in the cosmos, in other words, in part because it contains human beings who, driven by curiosity and a non-instrumental desire to address hard questions, attempt some philosophy. Philosophical enquiry makes the entire planet better than it would otherwise be. It helps constitute the awesomeness of Earth. Philosophy needs no further excuse.

The distinctive value of human science lies in its philosophical potency

Assume for a minute the worst about philosophy: that it has no instrumental value for other ends, that philosophers will never agree on the correct answers to anything, that studying ethics makes us no ethically better (as my own empirical research on the behaviour of ethicists tends to suggest), that philosophy is often just a tool to justify our vices, that our philosophical inclinations reveal more about our fixations and pathologies than about the world we seek to understand. Fine and (for the sake of argument) granted! Maybe it really is that bad. And yet: simply to pose a philosophical question is already a magnificent cognitive achievement – even just occasionally, even just in play. Our capacity for philosophical enquiry separates us from all other species. Earth becomes a very different and more interesting planet than it would otherwise be, regardless of any truths or........

© Aeon