Anti-reductionism and the Natural Order
Before moving on to specific examples of facts that can't be explained by current science and ideologies, we need to look a little closer at our options: materialism, anti-realism, and theism. Materialists think that physical facts (revealed by physical sciences) are the only things that can truly be said to exist, and everything in the cosmos can be understood in reference to these facts. So, things like subjective experience, intentions, goals, thinking, and a sense of value should all be able to be reduced down in this way: to the physical facts at their roots. As mentioned above, our mental abilities DO seem to depend in some way on our physical makeup: brains of different species, and brain regions, have observably different abilities and functions. So whatever explains how biology got to be the way it is must also explain how the mind came to be the way it is. But current sciences (evolutionary biology and psychology) can't fully explain either.
Since scientific "reductionism" has so far failed to adequately answer our questions, we should be fully justified in seeking out other, better options. And if reductionism turns out to be wrong, if it turns out that certain facts of nature (e.g., mind) cannot be reduced to physical matter, then this has some huge implications for our understanding of the nature of the cosmos. It would mean that materialism itself is false, that there is more than just matter, or that matter is not what we think it is. As Nagel puts it: "A genuine alternative to the reductionist program would require an account of how mind and everything that goes with it is inherent in the universe." This leaves two possibilities: either the universe is "not exclusively physical" or "there is no comprehensive order." In other words, either there's something 'extra' about the universe that will help us understand how mind fits in it all, or there's simply no explanation possible: the universe is fundamentally mysterious, and it's futile to even try understanding it. There is no reality, "because there are many kinds of truth and many kinds of thought …" In other words, "there is no truth" or "truth is relative."
Nagel doesn't think such an "anti-realist" stance holds up to the facts, or even just plain common sense. The facts suggest the opposite: that there is a universal order, that it's possible to understand it, and that mind is a basic aspect of nature. Support for this is actually found in one of the core conditions of science: the intelligibility of the world (i.e., able to be understood). When a scientist engages in an experiment, it's with the assumption that he or she will be able to learn and understand something from it. Rather than simply describing things and events, scientists fundamentally assume that something can also be understood. There's always a "because" hidden behind the bare facts. Water turns to ice because of the properties of its molecules at different temperatures. Water molecules form because of the properties of the elements hydrogen and oxygen. Hydrogen and oxygen differ because of their subatomic properties, etc. There are reasons the world is the way it is.
If there were nothing to discover--if humans either didn't have the ability to know anything, or there was no order in the universe to discover--we would have had no scientific discoveries and experiments wouldn't work--nothing would make sense. But that is not so. Scientists have discovered regularities in the working of the cosmos: physical laws with mathematical relationships, chemical laws governing the interactions of matter. The fact is, some explanations are better than others simply by the virtue that they give greater understanding and are more likely to be true. There is a benchmark (objective truth) by which they are judged.
How can we explain the fact that science seemingly and continuously discovers order in the universe? predicts outcomes? finds reasons? One answer is that it's 'just the way things are,' and nothing really explains it - we're just describing arbitrary facts. But that's just another cop-out. The very fact that there are facts to discover, that there is some 'sense' to be made of them, and that we can make sense of them, suggests that it makes more sense to assume that the fact that the universe can be understood "is itself part of the deepest explanation of why things are as they are." In other words, the universe is rational--it makes sense and it can be understood by minds--down to the very bottom. That would imply that the potential for minds was there at the very beginning. It seems kind of silly and unreasonable to imagine a universe that just happened to be comprehensible, and then for beings capable of discovering that fact, and comprehending it, to just happen to develop, all by chance. What are the odds?
When something appears arbitrary, "that is because there are further things we do not know, which explain why they are not arbitrary after all. … The intelligibility of the world is no accident. … Nature is such as to give rise to conscious beings with minds; and it is such as to be comprehensible to such beings. Ultimately, therefore, such beings should be comprehensible to themselves." Mind, and its potential, are built into the very fabric of the universe.
Natural science, with roots in a materialistic worldview, is one of the ways by which we make sense of the world, of its intelligibility. It may attempt a full understanding of everything in the universe, but it isn't very reassuring. How much of the universe can actually be explained simply in reference to physical laws? All of it? Nope. But even if this were the case, science would still have to be able to explain why science is possible in the first place--why the universe is comprehensible. It attempts to do this by explaining mind as a "highly specific biological side effect of the physical order." In other words, minds are just side effects of brains doing their thing (synapses firing, etc.).
But here materialism actually pulls the rug out from beneath itself. When scientists theorize about evolution, they're using faculties that are allegedly a product this evolution (perception, problem solving, reasoning). But can we trust a product of evolution to come to correct conclusions about evolution? Nagel doesn't think so. Here's why. The standards for survival are NOT the same as the standards for truth. Vision, for example, helped our ancestors survive. We trust our vision, but we know it could be faulty. The same would have to apply to our reasoning abilities: they would be generally reliable, but not in the sense we ordinarily take them for, with the precision that science, logic and math take for granted. If they were solely the result of chance natural selection, they'd just be tendencies, and we'd have no yardstick with which to measure their accuracy. The evolutionary hypothesis "does not explain why we are justified in relying on [our cognitive capacities] to correct other cognitive dispositions that lead us astray. … Evolutionary naturalism implies that we shouldn't take any of our convictions seriously, including the scientific world picture on which evolutionary naturalism itself depends."
To the materialist, ultimately, everything comes down to particle physics. So evolutionary biologists see the possibility of explaining life in terms of physics and chemistry. Human understanding of these physical laws has been refined over generations, and will continue to be refined. And since they've done such a good job in that time, there's every reason to think they'll continue to do so, eventually leading to "the most fundamental explanation of everything." Even if the details are still fuzzy, in principle, a full explanation should be possible, thus explaining life and minds capable of understanding all of this, all in terms of basic physical laws. But isn't that premature? The fact is, such an explanation has yet to appear. As long as we don't know, it seems arrogant to claim to know exactly how future discoveries will progress, and which possibilities are ruled out before the fact. And if physical laws explain everything, why do those laws hold in the first place? What is the origin of physical laws? And why are they the way they are, and not some other way?
The oldest answer is that God made them that way, bringing us to the third option: theism. (Anti-realism and theism were discussed above.) It's the polar opposite of materialism, seeing (God's) mind as the fundamental level that explains everything, "including the explanation of the basic and universal laws themselves." Physical laws are a consequence of mind, not the other way around, as in materialism. Through God's intention, we exist as mini-versions of Him, embodied with mind. The world is intelligible because God made it that way, and made us so that we could understand it. So, compared to materialism, theism actually attempts to answer some important questions: the origins of physical laws, mind, intelligibility.
Nagel sees theism as a cop-out, too, despite the fact that it reassuringly attempts to make sense of things ignored by materialism. Even then, it only offers a "very partial explanation of our place in the world." If the world really is intelligible, as it seems to be, it should be possible to understand it. But concepts like "God's mind" put a stumbling block in the way of complete understanding. We can't think our way past it. How, then, do we explain God's mind? How does He actually interact with the world? We can't know God's full purpose or understanding, and even if the world is intelligible as a result of God's intention, it isn't fully so to us--we lack a comprehensive account of the natural order of the cosmos. Since God is outside of the natural order, not governed by natural laws, theism "pushes the quest for intelligibility outside the world." When looked at in this way, theism amounts to "a denial that there is a comprehensive natural order." In other words, we can't explain it, so let's just say God did it. To fall back on divine intervention as an explanation is basically admitting that we can't explain it.
But Nagel wants to find a way to explain the cosmos that accounts for mind "as a fundamental principle of nature along with physical law," without falling back on divine intervention, and without explaining it away in terms of matter.
Materialism and theism have something in common, though. They both try to understand ourselves in terms of something outside of us. How do they do this? Well, any attempt to understand the universe has to start with us--our own point of view. It's our own observations and reasoning that begin the process of making a worldview, after all. We start with sensations and perceptions, without which we wouldn't have any data to work with. We perceive objects with our senses, patterns in the ways objects behave, etc. We also understand that we are sensing and perceiving: that some part of us is "seeing" all this, able to make generalizations, able to think about it all and come to conclusions. We know that we are perceiving subjects (i.e., we have consciousness), and that we perceive facts about an external reality. And both materialism and theism try to explain how we can trust our own faculties to engage in this process in the first place. (If we can't trust our perceptions and thoughts, how can we come to any firm conclusions?)
So, in theism, we extrapolate based on our understanding of ourselves (as conscious, creative beings, with intentions, reason, and values) to the ultimate level of God. A transcendent God makes sense all of the "facts" at our disposal, and we understand ourselves and our place in the universe in relation to God, as the ultimate source of consciousness, creativity, intention, reason, and value. We trust our initial sensations and perceptions because God would not deceive us. In materialism, we extrapolate our scientific understanding based on our study of some parts of the world, to the whole of the world. We observe interactions between matter, generalize laws to explain and predict the regularity that is apparent all around us, and we trust the initial sensations and perceptions that lead up to all this because we wouldn't have survived if we couldn't reach generally reliable beliefs about the facts of the world (e.g., that's a bear, not an acorn).
Both materialism and theism attempt a larger world view that transcends the starting points--the basic raw material facts. "And to succeed, that larger world view must encompass itself." This means that our new, larger understanding needs to explain and justify itself, the way theism justifies its conclusions because God wouldn't lie, or materialism justifies itself because natural selection wouldn't produce untrustworthy "reality-reading machines." However, these justifications leaves a lot to be desired, as we've just seen above. Both positions undermine themselves (theism implicitly denies the intelligibility of the world, and materialism/evolution can't account for it). The point is, we seem naturally drawn to a larger worldview--a transcendent worldview--that encompasses everything, transcends an understanding limited to just ourselves, and places us within a larger whole.
Nagel thinks there's a third option for such a transcendent world view, which is plausible, "more modest and perhaps more realistic. … The hope is not to discover a foundation that makes our knowledge unassailably secure to but find a way of understanding ourselves that is not radically self-undermining, and that does not require us to deny the obvious." We can't be absolutely sure about our knowledge--it's always possible that our beliefs are systematically false (anti-realism rears its ugly face again). But we can be careful and consistent, and compare various theories, to come up with one that doesn't contradict itself or ignore facts. And it's not unreasonable to test hypotheses by using common sense - "ordinary judgments in which we have a very high confidence" - in fact, we have to, if we're going to account for all the facts at our disposal.
So how can we combine what we do know into a coherent world view? First of all, we know that "the world generates conscious beings capable of recognizing reasons for action and belief, distinguishing some necessary truths, and evaluating the evidence for alternative hypotheses about the natural order." In other words, the universe produces thinking, rational beings, able to grasp objective truths about reality. We also see "our clearest moral and logical reasonings" as objectively valid. We NKOW when an answer is right or wrong, or when an action is right or wrong. A worldview must explain this confidence. And even though we don't have such a worldview right now, we still go on using such faculties in our everyday lives, constructing theories based on perception, reason, logic. We still know that 2+2=4, even if we don't know exactly how and why we know it. A good theory must explain "the existence of conscious minds and their access to the evident truths of ethics and mathematics." So, why is math true? And how is it possible for us to grasp these truths? This all-expansive worldview must explain both matter and mind (so it will have both materialist and rational parts to it). And everything present now in the universe (including consciousness, perception, desire, action, etc.) must have been somehow inherent as possibilities long before life appeared and these potentials were actualized. And the very fact that these possibilities were actualized needs to have have been a significant likelihood (not a vanishingly rare coincidence), given the structure of the universe.
In other words, we have to explain why everything as it is came to be the way it is, why it was likely that it happened this way, and what it is about the very structure of the cosmos that made it likely. No shortcuts. No coincidences.
Nagel's summarizes his argument so far: "the respective inadequacies of materialism and theism as transcendent conceptions, and the impossibility of abandoning the search for a transcendent view of our place in the universe, lead to the hope for an expanded but still naturalistic understanding that avoids psychophysical reductionism. The essential character of such an understanding would be to explain the appearance of life, consciousness, reason, and knowledge neither as accidental side effects of the physical laws of nature nor as the result of intentional intervention in nature from without but as an unsurprising if not inevitable consequence of the order that governs the natural world from within. That order would have to include physical law, but if life is not just a physical phenomenon, the origin and evolution of life and mind will not be explainable by physics and chemistry alone. An expanded, but still unified, form of explanation will be needed, and I suspect it will have to include teleological elements."
