From Bacteria to Bach and Back

Part I: Turning Our World Upside Down

1. Introduction

• How come there are minds?
  • Minds evolved and created thinking tools that eventually enabled minds to know how minds evolved, and even to know how these tools enabled them to know what minds are.
  • What thinking tools? The simplest, on which all the others depend in various ways, are spoken words, followed by reading, writing, and arithmetic, followed by navigation and mapmaking, apprenticeship practices, and all the concrete devices for extracting and manipulating information that we have invented: compass, telescope, microscope, camera, computer, the Internet, and so on.
  • These, in turn, fill our lives with technology and science, permitting us to know many things not known by other species. We know there are bacteria. Even bacteria don't know there are bacteria.
  • Our minds are different. It takes thinking tools to understand what bacteria are, and we're the only species (so far) endowed with an elaborate kit of thinking tools.
• A birds-eye view of the journey:
  • Life has been around on Earth for around 4bn years. The first 2bn were spent optimizing the machinery for self-maintenance, energy acquisition and reproduction, and the only living things were relatively simple, single-celled entities - bacteria or their cousins, archaea: the prokaryotes.
  • Then an amazing thing happened. Two different prokaryotes collided and instead of one eating the other, it let it go on living, and, by dumb luck, found itself fitter, more competent in some way that mattered, than it had been before. This was perhaps the first successful instance of technology transfer. A fortuitous mutation almost never happens, but evolution depends on those rarest of rare events. This is the birth of the eukaryotes
  • Every living thing big enough to be visible to the naked eye is a multicellular eukaryote.
  • The Cambrian Explosion, which occurred over several million years about 530m ya, saw the sudden arrival of a bounty of new life forms.
  • The "MacCready Explosion", at the dawn of human agriculture, about 10k ya, transformed the terrestrial vertebrate biomass (excluding insects, other invertebrates, and marine animals). At the beginning, humans plus their livestock and pets make up only 0.1%, and now we make up 98% (mostly cattle). This explosion is based on three factors - population, technology, and intelligence (our so-called native intelligence depends on both our technology and our population numbers).
• Dennett identified the "romantic" and "killjoy" sides of the duel over the stature of animal minds. We are not the God-like geniuses we think we are, but animals are not so smart either, and yet both humans and other animals are admirably equipped to deal "brilliantly" with many of the challenges thrown at them.

2. Before Bacteria and Bach

• until there were systems that could be strictly called reproducing systems, the processes at work were only proto-evolutionary, semi-Darwinian, partial analogues of proper evolution by natural selection; they were processes that raised the likelihood that various combinations of ingredients would arise and persist, concentrating the feedstock molecules until this eventually led to the origin of life.
• A living thing must capture enough energy and materials, and fend off its own destruction long enough to construct a good enough replica of itself.
• The reverse-engineering perspective is ubiquitous in biology and is obligatory in investigations of the origin of life. It always involves some kind of optimality considerations: What is the simplest chemical structure that could possibly do x? Or would phenomenon x be stable enough to sustain process y?
• Orgel's second rule: "Evolution is cleverer than you are."
• Here is an example of a possible gambit in the origin of life:
  • It is tempting to assume that the very first living thing capable of reproducing must have been the simples possible living thing (given the existing conditions on the planet at the time).
  • Make the simples replicator you can imagine and then build on that foundation.
  • But this is by no means necessary. It is possible, and more likely, I think, that a rather inelegantly complicated, expensive, slow, Rub-Goldberg conglomeration of objets trouvés was the first real replicator, and after it got the replication ball rolling, this ungainly replicator was repeatedly simplified in competition with its kin.
  • Many of the most baffling magic tricks depend on the audience no imagining the ridiculously extravagant lengths magicians will go to in order to achieve a baffling effect. If you want to reverse-engineer magicians, you should always remind yourself that they have no shame, no abhorrence of bizarre expenditures for tiny effects that they can then exploit. Nature, similarly, has no shame - and no budget, and all the time in the world.
• Adaptionism is alive and well; reverse-engineering is still the royal road to discovery in biology.

3. On the Origin of Reasons

• There are three strategies to adopt when trying to understand, explain, and predict phenomena:
  • The physical stance - is the least risky but also the most difficult; you treat the phenomenon as obeying the laws of physics, and use physics to predict what will happen next.
  • The design stance - is only for things that have been designed, either artifacts or living things or their parts, and have functions or purposes.
  • The intentional stance - works primarily for things that are designed to use information to accomplish their functions. It works by treating the thing as a rational agent, attributing "beliefs" and "desires" and "rationality" to the thing, and predicting that it will act rationally.
• Evolution by natural selection is not itself a designed thing, an agent with purposes, but it acts as if it were. It is a set of processes that "find" and "track" reasons for things to be arranged one way rather than another.
• The reasons found by human designers are typically (but not always) represented in the minds of the designers, whereas the reasons uncovered by natural selection are represented for the first time by those human investigators who succeed in reverse-engineering Nature's productions.
• Our human world of reasons grew out of a world where there were no reasons.
• Two meanings of the word "why":
  • What for - "Why are you handing me your camera?"
  • How come - "Why does ice float?" This is asking for a cause or a process narrative
• Evolution by natural selection starts with "how come" and arrives at "what for". We start with a lifeless world in which there are no reasons, no purposes at all, but there are processes that happen.
• A central feature of human interaction, and one of the features unique to our species, is the activity of asking others to explain themselves, to justify their choices and actions, and then judging, endorsing, rebutting their answers, in recursive rounds of the "why?" game.
• Our capacity to respond appropriately in this reason-checking activity is the root of responsibility. Those who cannot explain themselves or cannot be moved by the reasons offered by others, those who are "dead to" the persuasions of advisors, are rightly judges to be of diminished responsibility and are treated differently by the law.
• The "logical space of reasons" is bound by norms, by mutual recognition of how things ought to go. Wherever there are reasons, there is room and need for some kind of justification and the possibility of correction when something goes wrong. This normativity is the foundation of ethics.
• But there are two kinds of norms and corrections:
  • social normativity - concerned with social norms, practice, and collaboration
  • instrumental normativity - concerned with quality control or efficiency, the norms of engineering
• Natural selection is an algorithmic process, a collection of sorting algorithms that are themselves composed of generate-and-test algorithms.
• In the prebiotic or abiotic world (before life), there were cycles at many spatio-temporal scales: seasons, night and day, tides, the water cycle, and thousands of chemical cycles discoverable at the atomic and molecular level, gradually changing the conditions in the world and thus raising the probability that something new will happen.
• This led to differential persistence, some temporary combinations of parts hang around longer than others. The rich can get richer, even though they can't yet bequeath their riches to descendants.
• Differential persistence must then somehow gradually turn into differential reproduction.
• "Serendipity" is when something good happens randomly, while "clobbering" is when something bad happens randomly.
• Walls or membranes that are randomly persisted are serendipitous in that they allow internal cycles to operate for a time without interference, and we see the engineering necessity of membranes to house the collection of chemical cycles - the Krebs cycle and thousands of others - that together permit life to emerge.
• Before we can have competent reproducers, we have to have competetent persisters. We are witnessing an automatic (algorithmic) paring away of the nonfunctional, crowded out by the functional.
• There are reasons why the parts are shaped and ordered as they are and this is the birth of reasons. Through Darwinism about Darwinism, we see the gradual emergence of the species of reasons out of the species of mere causes, what fors out of how comes*
• Natural selection is an automatic reason-finders, which "discovers" and "endorses" and "focuses" reasons over many generations.
• If there happens to be a "difference that happens to make a difference" then we have the germ of a reason, a proto-reason, and when this is selected to persist longer, then we can see emerge the accumulation of function by a process that blindly tracks reasons.
• Reasons existed before there were reasoners. There are reasons why trees spread their branches but they are not, in any strong sense, the trees' reasons. They don't "have" the reasons and they don't need to have the reasons.
• Darwin didn't extinguish teleology - he naturalized it.
• Reverse-engineering in biology is a descendant of reason-giving-judging.
• The evolution of what for from how come can be seen in the way we interpret the gradual emergence of living things via a cascade of prebiotic cycles. Free-floating rationales emerge as the reasons why some features exist; they do not presuppose intelligent designers, even though the designs that emerge are extraordinarily good.