Naturalism is the default cultural view of the modern world. It’s a story that’s repeated so often, people accept it without questioning its truth. The naturalist story says that as scientific knowledge advances, it’s showing that the supernatural doesn’t exist and we live in an insentient and purposeless universe.
Naturalists present this story as the most rational world view, but in fact it’s based on a logical mistake. It confuses a method with a metaphysics and mistakes scientific data for philosophical facts.
There’s a difference between naturalism as a method, and naturalism as a metaphysics. Science is a naturalist method. Naturalism as metaphysics is the philosophical claim that nature is the only thing that exists. In other words, it’s not a scientific claim that nothing supernatural exists or there is nothing beyond nature. It’s a philosophical interpretation of scientific theories that goes beyond empirical confirmation.
Science is an extraordinarily successful method for discovering facts about the world. But a method is a way of investigating and gathering data, whereas metaphysics is an explanatory interpretation of the data. Metaphysical claims aren’t scientific theories, they’re not interpretations of data that are used to make predictions within a limited frame of reference. Metaphysics uses the data to make inferences about the most fundamental features of reality.
Naturalism as metaphysics claims the success of the scientific method is evidence that supports an inference about the fundamental nature of the entire reality. The problem with this idea is the scientific method intentionally restricts its explanations to a limited range of properties. Only empirical and measurable properties are included in scientific explanations.
A metal detector only finds metal objects, but we wouldn’t interpret this to mean metal is the only thing that exists, it’s just a consequence of the properties we’ve chosen to select. If we intentionally restrict our view of the world to certain properties, it doesn’t mean the world itself consists only of those properties. To define a certain explanatory category doesn’t mean reality actually contains that category.
Yet this is the same mistake people make when they believe science has shown nothing supernatural exists. The reason science hasn’t found anything supernatural is because it only detects certain observable causal structures, not all of reality.
Science intentionally restricts its explanations to the natural world, and the natural world is understood to mean the things that can be investigated with science. To interpret this to mean that only natural things exist is a logical circle.
There’s no dispute that science is successful within its explanatory domain, but our focus isn’t the success of the naturalist method, it’s the interpretation of the success of science to claim nothing beyond the properties studied by science exists. To judge the truth of this interpretation we need to investigate the reasons and evidence we have to think naturalism as a metaphysics is true.
Naturalism presents itself as the most rational view, but when we critically analyse naturalism as a metaphysics, we find it assumes what it’s supposed to prove.
Naturalism has no clear definition of natural
If we’re to judge the truth of the claim that “everything is natural,” the first thing we need to ask is: What does the word natural mean?
We’re told that nature is all that exists, but the word natural has no clear definition. This problem was most famously expressed by the philosopher Carl Hempel and is known as Hempel’s dilemma.
Generally, people are motivated to accept naturalism because of the success of the natural sciences. Which means the word natural can be broadly understood to mean “the phenomena studied by the natural sciences.”
If this is our definition, then to demonstrate metaphysical naturalism is true, we must explain all phenomena in a physical framework. Now the definition runs into a problem.
If natural or physical is defined based on the current laws of physics, then naturalism is false. After all, no one thinks that current physics is complete and mental properties stand stubbornly outside the realm of physics.
If we judge on some unknown future laws of physics we find naturalism is vacuous, because no one knows what that ideal physics consists of. The unknown future physics has no specified boundaries, it might include mental states, agency or teleological properties. Which makes this definition of natural indeterminate.
When the naturalist tells us that everything is natural, even they don’t know exactly what that means. And if we try and define it, naturalism is false if defined by current physics, or trivial if defined by some unknown future physics.
This problem might not seem so pronounced if naturalism were offered as a provisional belief or humble suggestion. But it’s usually delivered with such confidence that anyone who disagrees is assumed to be rejecting scientific authority rather than questioning philosophical interpretations of it.
We’re offered a grand thesis about the truth of the whole of reality that can’t even define its central term.
This isn’t surprising if you realise that naturalism isn’t a thesis that starts by observing the world and then logically constructing its metaphysics to explain those observations. Instead, naturalism treats a methodological constraint as an ontological conclusion.
Naturalism can’t define its central term because nature isn’t an observed category in the world, but a category created as a method to investigate the world. Naturalism retrofits reality to match its preferred method of investigation rather than the other way around.
Naturalism can’t explain why the universe exists
Most people think science will one day explain why the universe exists. Popular science commentary often misleadingly suggests cosmology is working on that question.
But science can never explain why nature exists, it can only explain things that already exist and must presuppose the existence of laws and structures. Science is limited to telling us why the different arrangements of existing stuff changes over time. It can describe the initial state of things that already exist, but science can’t tell us why that stuff exists, or why we have this stuff rather than some other kind of stuff, or even no stuff at all.
Naturalism as a philosophy is in the same situation, it can’t go beyond nature to say what caused nature to exist. It can’t admit the explanatory need to go beyond nature to explain why it exists, because that requires explanatory resources not available within naturalism’s specified conceptual boundaries.
The question of cosmic origins can’t be answered by referring to physical properties, because if something possesses physical properties, by definition, it already exists. All physical events and causes are within the history of nature. But the question being asked is about the possibility of such a history in the first place and the existence of the natural order itself.
A common naturalist response is to say there is no reason the universe exists, the universe is a brute fact. Brute fact isn’t saying there is a reason but we don’t know what it is. A brute fact is saying there is no reason.
That isn’t an explanation but a decision to stop asking, and calling the question unanswerable doesn’t make it go away. We wouldn’t accept that an ordinary object exists for no reason, and the question isn’t less pressing when the object is the universe.
Naturalism claims that only natural things exist, but is incapable of explaining the fact of that existence. This isn’t an explanatory hole that can one day be filled, this is a structural hole created by the definition of nature. The existence of naturalism’s designated category of reality can’t be explained in principle, but it simultaneously claims to provide a complete description of reality.
Naturalism can’t explain why there are uniform and orderly laws of nature
Just as naturalism can’t explain why nature exists, it can’t explain why our universe has these particular laws of nature. The fact that the universe is governed by uniform and orderly laws must be taken for granted. Not only does nature have law-like regularities, the fundamental forces of nature are balanced with a delicate precision. Upset this delicate balance and the universe could have collapsed in on itself before getting started. No atoms could form, which means no stars, no planets, no carbon, and no life.
The only explanation available to naturalism is chance. It just happened to be the case. But chance is a euphemism for not only unknown, but unanswerable.
In both instances of explaining why nature exists and why it has the properties it does, we’re offered euphemisms (brute fact and chance) to disguise the fact these questions are unanswerable within the logical boundaries naturalism allows.
Naturalism can’t explain the conscious dimensions of reality
Naturalism must deny our shared experience of ourselves and the world to make the world conform to its explanation. A good explanation does the opposite, the explanation conforms to the observed nature of the world.
Naturalism can’t explain personal phenomena. The hard problem of consciousness is really an impossible problem for naturalism. Mental properties like conscious experience, intentions, purposes, meaning and values can’t be reduced to natural properties.
Naturalism can’t explain how these immaterial properties could arise from the interactions of insentient matter. All these immaterial properties fit uncomfortably in the naturalist world view and must be reduced to functions or structure, some even go as far as declaring them an illusion. Our experiences are reduced to a mere appearance, not the real world, because reality must be something physical.
This is why many naturalists deny the most fundamental truths of our experience of ourselves and the world. We’re often told we have no free will, and morality consists of nothing more than the rules that allow societies to function.
All these explanatory defects are the consequence of naturalism starting with its conclusion. This is why it can’t define its central term, can’t explain why nature exists or is orderly and intelligible or produces purpose, meaning and values.
Naturalism can’t confirm the truth of its doctrine because doing that would require going beyond its self-imposed boundaries. It’s a conclusion about the entire reality that is beyond anything the natural sciences can test.
The impression people have that naturalism is a viable explanation relies on conflating science and metaphysics. It trades on the prestige of science to suggest the discoveries of science demonstrate the philosophical conclusions. But naturalism as a metaphysical claim goes far beyond the scientific data to make claims about the entire reality. Claims that aren’t justified by any empirical discoveries, logic or experience.
Rejecting naturalism as a metaphysics doesn’t mean rejecting naturalist methods. It means rejecting the idea a successful method of investigation can be extended to conclusions that apply to the whole of reality.
This is why I’m not a naturalist. Not because I don’t take science seriously, but because I also take seriously all the features of reality that need explaining, including the ones naturalism lacks the resources to explain.
For readers who want to explore any of these arguments in more depth these articles go into more detail…
The Fingerprints of God – a finely tuned universe
