Paper I — General: References
90 SOURCES · 30 QUESTIONS · ALL FREELY AVAILABLE
Each source carries a technical description and a plain one; authors’ own pages and encyclopaedia entries are linked where they exist. Every address on this page was verified live at publication. The paper itself: Paper I.
1. Is the genome a program?
Surveys informational and programme talk in genetics — teleosemantic, causal, and deflationary readings — and what each licenses.
In plain terms: The standing scholarly audit of whether genes literally carry information and instructions, or whether that is a useful manner of speaking.
Nature's gift to science (Nobel lecture)
Brenner's account of the genetic programme viewpoint and of computing the organism from its cellular logic.
In plain terms: A founder of molecular biology, and the field's sharpest wit, on treating the cell as a machine that runs its DNA.
Examines mechanism, reduction, and the gene concept — the load-bearing notions behind the programme metaphor.
In plain terms: What molecular biology's central ideas actually assert, and where the software picture of the gene starts to strain.
Background: Genome · Gene regulatory network
2. What distinguishes a law of nature from an accidental regularity?
The systematic survey: Humean best-systems accounts against governing and necessitarian accounts, with the accidental-regularity problem central.
In plain terms: The main scholarly map of what separates a genuine law from a pattern that merely happens to hold.
A regularist's case that lawhood adds nothing metaphysical to universal truth — the deflationary pole of the debate.
In plain terms: The contrarian position stated plainly: perhaps laws are just the true generalisations, and necessity is our projection.
An enquiry concerning human understanding
The source of the problem: necessary connexion reduced to constant conjunction plus habit, from which all later accounts descend.
In plain terms: The classic that started the trouble, free in full: Hume's argument that we never observe necessity, only regularity.
Background: Scientific law · Problem of induction
3. Is mathematics discovered or constructed? Answer without appeal to authority.
Surveys logicism, intuitionism, formalism, and structuralism — the positions among which discovery and construction divide the spoils.
In plain terms: The scholarly field guide to every serious answer to whether mathematics is found or made.
Platonism in the philosophy of mathematics
The discovery side made precise: existence, abstractness, independence — and the epistemological access problem it must answer.
In plain terms: The strongest case that mathematical objects are real and waiting to be found, together with its famous difficulty: how would we ever touch them?
The unreasonable effectiveness of mathematics
A working mathematician's partial deflation: selection effects and human shaping explain some, not all, of mathematics' fit to the world.
In plain terms: An engineer-mathematician argues we partly construct the fit between mathematics and nature — and honestly admits the residue he cannot explain away.
Background: Philosophy of mathematics · Foundations of mathematics
4. When, if ever, is a computer simulation an experiment?
Computer simulations in science
The central treatment of simulation epistemology: verification, validation, and the contested analogy with experiment.
In plain terms: The standing scholarly answer to when running a program counts as finding something out about the world.
Studies of non linear problems (LA-1940)
The founding numerical experiment: expected thermalisation fails, recurrences appear — a discovery made only in silico.
In plain terms: The original report, free from the national archive, of the first time a computer run surprised physics like a laboratory would.
The Fermi–Pasta–Ulam problem: fifty years of progress
Reviews what half a century of analysis extracted from that first simulation — solitons, chaos thresholds, slow equipartition.
In plain terms: What became of the surprise: how one early computer experiment seeded several fields of mathematics and physics.
Background: Computer simulation · Fermi–Pasta–Ulam–Tsingou problem
5. Does reduction explain, or only redescribe?
Models of reduction from Nagel onward, and the criteria separating explanatory reduction from mere translation.
In plain terms: The scholarly ledger of what it takes for a lower-level story to genuinely explain, not just restate, a higher-level one.
What explanation itself requires — the standard against which redescription is measured.
In plain terms: Before judging whether reduction explains, one needs a theory of explaining; this is the field's best summary of the candidates.
The classic obstruction: kinds realised many ways resist type reduction, constraining what reduction can claim to explain.
In plain terms: The sharpest argument that some sciences cannot collapse into physics: their categories cut across physical kinds.
Background: Reductionism · Multiple realizability
6. What would it take to show that a phenomenon is emergent rather than merely complicated?
The load-bearing distinction: deducibility-in-principle (weak) versus its failure (strong), with candidate instances of each.
In plain terms: The short paper that gave the debate its vocabulary — two precise senses of 'emergent', only one of which would shake physics.
Taxonomy of emergence claims — epistemic, ontological, causal — and the evidential burden each carries.
In plain terms: The catalogue of everything 'emergent' has been used to mean, and what it would take to establish each.
Complementary survey, historically ordered from British emergentism through contemporary physicalism.
In plain terms: A second free reference work's account, useful for its history: the idea's rise, fall, and quantitative revival.
Background: Emergence · Complex system
7. Is there a fact of the matter about the arrow of time?
The thermodynamic arrow: puzzles and pseudo-puzzles
Enforces the atemporal viewpoint: which arrow-of-time questions survive when temporal double standards are removed.
In plain terms: A philosopher shows that half the puzzles about time's direction dissolve once we stop assuming the answer while asking the question.
Thermodynamic asymmetry in time
Whether the asymmetry is fundamental, reducible to cosmology, or perspectival — the fact-of-the-matter question directly addressed.
In plain terms: The balanced scholarly account of whether time's one-way character is in the world, in the boundary conditions, or in us.
The metaphysical setting: tensed versus tenseless theories, against which physical arrows are interpreted.
In plain terms: Steps back to the prior question — whether passage itself is real — without which the arrow debate cannot be scored.
Background: Arrow of time · Entropy (arrow of time)
8. Why is the universe amenable to mathematics at all?
The unreasonable effectiveness of mathematics in the natural sciences
The essay that fixed the problem: mathematical concepts developed for their own sake repeatedly furnish exact physics, unaccountably.
In plain terms: The famous free essay posing the question in its purest form — why should human-made mathematics fit the universe at all?
The limiting answer: the universe is amenable to mathematics because it is a mathematical structure; effectiveness becomes identity.
In plain terms: The boldest reply on record — the fit is perfect because the world simply is mathematics — argued at full length, free.
Indispensability arguments in the philosophy of mathematics
Runs the inference in reverse: mathematics' role in physics as evidence for mathematical reality, with the counterarguments.
In plain terms: Turns the question into an argument: if physics cannot do without mathematics, does that show numbers exist?
Background: The Unreasonable Effectiveness of Mathematics in the Natural Sciences · Mathematical universe hypothesis
9. Can a measurement have no observer?
Philosophical issues in quantum theory
Frames the observer question exactly: what constitutes measurement across collapse, Everettian, and epistemic approaches.
In plain terms: The reference account of the quantum measurement dispute, on which the observer's necessity is precisely what divides the schools.
Any system can play observer: measurement as relative fact-formation between systems, with no privileged consciousness.
In plain terms: The founding paper of the view that measurement needs no mind — any interaction registers facts, but only relative to the participants.
QBism, the perimeter of quantum Bayesianism
The opposite pole: quantum states as agents' credences, making measurement constitutively first-personal.
In plain terms: The strongest modern case that the observer is ineliminable — quantum theory read as each user's betting manual.
Background: Wigner's friend · Quantum Bayesianism
10. What is the smallest amount of evidence that would rationally overturn a well-confirmed theory?
The quantitative framework in which the question has an answer: priors, likelihood ratios, and rational updating.
In plain terms: The system that turns 'how much evidence is enough?' into arithmetic — and the arguments that the arithmetic is the right rule.
Measures of evidential support and their paradoxes — what 'well-confirmed' can defensibly mean.
In plain terms: The careful accounting of what it is for evidence to support a theory, including the traps that catch intuition.
The theorem's content and scope conditions — the engine by which small evidence can rationally overturn large priors.
In plain terms: The rule itself, patiently explained: how a single sharp observation can outweigh years of confirmation.
Background: Bayesian inference · Falsifiability
11. Is information physical?
Notes on Landauer's principle, reversible computation, and Maxwell's demon
The physical-cost side of the slogan: erasure's kT ln 2 bound and its role in exorcising Maxwell's demon.
In plain terms: The case that information is physical because destroying it necessarily produces heat — by the physicist who nailed the argument down.
Distinguishes Shannon, semantic, and algorithmic senses — which of them Landauer's slogan can and cannot be about.
In plain terms: Sorts out what 'information' means in the first place, so the slogan can be tested rather than merely repeated.
Computational capacity of the universe
Takes the slogan to its limit: bounds on the bits and operations the physical universe can have registered.
In plain terms: If information is physical, the universe has a memory size and a clock speed — here both are calculated.
Background: Landauer's principle · Entropy in thermodynamics and information theory
12. Distinguish randomness from ignorance.
Separates objective chance from product randomness and both from ignorance, with the formal theories of each.
In plain terms: Exactly the question, treated at length: when is unpredictability in the world, and when only in our heads?
Kolmogorov–Solomonoff foundations: randomness as incompressibility, giving an observer-independent criterion.
In plain terms: The mathematical test that makes randomness objective: a sequence is random when no shorter description of it exists.
Interpretations of probability
The interpretive menu — frequency, propensity, credence — on which the randomness/ignorance divide is drawn.
In plain terms: The standing guide to what probability statements could possibly be about, from world-chances to degrees of belief.
Background: Randomness · Algorithmic information theory
13. Could two theories be empirically equivalent yet not the same theory?
Underdetermination of scientific theory
The direct treatment: whether empirically equivalent rivals genuinely occur, and what they would show about theory identity.
In plain terms: The scholarly record on whether two theories could fit every possible observation yet still say different things.
One resolution: equivalent formulations share structure, and structure is the theory's content.
In plain terms: A serious way out — perhaps what a theory really says is only its web of relations, which equivalent rivals share.
The stakes: underdetermination as the standing objection to reading theories as true descriptions.
In plain terms: Why the question matters — if evidence cannot decide between rivals, what does believing a theory amount to?
Background: Underdetermination · Duhem–Quine thesis
14. Is life a physical kind or a historical accident?
Definitions of life — metabolic, Darwinian, thermodynamic — and whether 'life' names a natural kind at all.
In plain terms: The scholarly survey of every attempt to say what life is, and of the suspicion that it may not be one thing.
The algorithmic origins of life
Proposes informational causation as life's physical signature — a kind-hood claim locatable in dynamics.
In plain terms: The case that life is a genuine physical category: matter in which information takes causal charge.
Statistical physics of self-replication
Derives dissipative bounds favouring replication, suggesting lifelike order as a thermodynamic tendency rather than accident.
In plain terms: A physics argument that something like life is what driven matter is inclined to do — tilting the question toward 'kind'.
Background: Life · Abiogenesis
15. What does it mean to say a constant is "fine-tuned"?
What the claim asserts — life-permitting ranges narrow under some measure — and the measure problem that haunts it.
In plain terms: The careful statement of what 'fine-tuned' means, and of the hidden difficulty: narrow compared with what?
The fine-tuning of the universe for intelligent life
The physics case: surveys of parameter variations and their catastrophic consequences, with the calculations displayed.
In plain terms: The evidence itself, freely readable: what actually happens to stars, chemistry, and complexity when the dials are turned.
Screams for explanation: finetuning and naturalness in the foundations of physics
The dissent: naturalness and fine-tuning arguments as aesthetic, probabilistically ill-founded criteria.
In plain terms: The sceptic's brief — that 'fine-tuned' smuggles in probability judgements nobody is entitled to make.
Background: Fine-tuned universe · Anthropic principle
16. Can a proof be too long to be a proof?
Formal proof — the four-color theorem
The complete machine verification of Appel–Haken, converting an unsurveyable proof into a checkable kernel.
In plain terms: How the most notorious too-long proof was tamed: not by shortening it, but by making a machine's checking itself trustworthy.
The general case for formal verification when referee surveyability fails, by the prover of the Kepler conjecture.
In plain terms: A mathematician whose own proof outran human readers explains what should count as proof once no one can read it all.
Solving and verifying the Boolean Pythagorean triples problem via cube-and-conquer
The 200-terabyte proof, with a 68 GB checkable certificate — the length question posed at industrial scale.
In plain terms: The largest proof ever produced, freely documented: too long for any human by twelve orders of magnitude, yet independently checkable.
Background: Computer-assisted proof · Four color theorem
17. Is temperature real?
Consistent thermostatistics forbids negative absolute temperatures
Gibbs versus Boltzmann entropy adjudicated: whether temperature's very definition is convention-laden.
In plain terms: A live modern dispute in which physicists disagree about what temperature even is — evidence the concept is less innocent than it looks.
Philosophy of statistical mechanics
Temperature's reduction to mean kinetic energy examined: what survives, what is idealisation, what is definitional.
In plain terms: The scholarly account of whether temperature is a deep property of matter or a spectacularly useful summary.
Information theory and statistical mechanics
The inferential reading: temperature as a Lagrange multiplier of maximum-entropy inference, real as constraint, not stuff.
In plain terms: The classic paper on which temperature is something like an exchange rate in our best bookkeeping of energy — objective, but not a substance.
Background: Temperature · Negative temperature
18. Why should the simpler hypothesis be preferred? Give a non-circular answer.
The justificatory options — pragmatic, probabilistic, aesthetic — and the circularity threat to each.
In plain terms: The full survey of attempts to say why simpler theories deserve preference, and how most quietly assume what they set out to prove.
The strongest non-circular candidate: Solomonoff's universal prior, in which shorter programmes are provably better predictors.
In plain terms: The mathematical result closest to an honest answer: in a precise sense, betting on simplicity is the optimal way to learn.
The deeper regress into which simplicity's justification drains — Hume's problem in modern dress.
In plain terms: Why the question is so hard: any defence of simplicity must first survive the old puzzle of trusting experience at all.
Background: Occam's razor · Solomonoff's theory of inductive inference
19. Does biology have laws?
Includes the laws debate: contingency, ceteris paribus generalisations, and candidate exceptions like selection itself.
In plain terms: The field's own survey of whether biology has laws or only histories, with the best candidates for each verdict.
The criteria for lawhood against which biological generalisations are measured and mostly fail — or the criteria fail.
In plain terms: What a law would have to be, so the reader can judge whether Mendel or Darwin ever wrote one.
The structure of evolutionary theory — principles, models, contingency — the test case for biological lawhood.
In plain terms: Biology's central theory laid out, so one can ask directly: is anything in it a law, or is it magnificent bookkeeping of accidents?
Background: Philosophy of biology · Natural selection
20. What is conserved when energy is conserved?
Invariant variation problems (English translation of Noether 1918)
The answer's source: energy conservation as the conserved current of time-translation symmetry.
In plain terms: The original theorem, freely translated, revealing what energy conservation is really about: the laws not caring what time it is.
Noether's theorem in a nutshell
Compact derivation making the symmetry–conservation correspondence transparent enough to answer the question in one line.
In plain terms: A free masterclass converting 'energy is conserved' from mystery into consequence.
Is energy conserved in general relativity?
The instructive failure mode: where time-translation symmetry lapses, 'what is conserved' becomes genuinely subtle.
In plain terms: The honest complication, freely explained: in an expanding universe the familiar answer wobbles — which shows what the answer was made of.
Background: Conservation of energy · Noether's theorem
21. Is the periodic table a discovery about chemistry or about physics?
The reduction question for chemistry stated exactly: what quantum mechanics does and does not deliver of the periodic system.
In plain terms: The scholarly account of whether chemistry's great chart belongs to chemistry or was physics all along.
The periodic table and the physics that drives it
The physics case in full: relativistic quantum electronic structure generating, and at the table's edges deforming, periodicity.
In plain terms: The strongest free statement of the physics claim — the table calculated from first principles, including where it starts to bend.
The general framework the question instantiates — with chemistry the literature's favourite contested example.
In plain terms: The wider debate about sciences absorbing one another, in which the periodic table is the show exhibit.
Background: Periodic table · Philosophy of chemistry
22. Can a scientific model be true?
What models are — idealised structures, fictions, mediators — and in what sense truth can attach to them.
In plain terms: The standard survey of what scientific models are and whether 'true' is even the right compliment to pay one.
The position for which model truth matters: approximate truth, selective realism, and their critics.
In plain terms: The case that our best models are telling us how the world really is — and the standing objections.
A refinement fitted to idealisation: models true of structure while false of furniture.
In plain terms: A middle way — perhaps a model can be true about the pattern of things while wrong about the things.
Background: Scientific modelling · Map–territory relation
23. What is the difference between a symmetry and a redundancy in description?
Symmetries, symmetry breaking, gauge symmetries
The rigorous form of the distinction: global symmetries act on physical states; gauge 'symmetries' identify redundant descriptions.
In plain terms: A mathematically exact free essay on the question's very distinction — which symmetries are nature's and which are our notation's.
Symmetry and symmetry breaking
The interpretive criteria — observability, direct empirical significance — by which symmetry is told from redundancy.
In plain terms: The philosophers' tests for whether a symmetry could ever be observed, or is bookkeeping by construction.
The complication: gauge variables as relational handles, so 'mere redundancy' undersells their coupling role.
In plain terms: The twist in the tale — the supposedly empty notation turns out to be how systems connect to one another.
Background: Symmetry (physics) · Gauge theory
24. Would a complete physics of the brain leave anything unexplained?
Facing up to the problem of consciousness
The canonical argument that functional-physical explanation leaves experience itself unaccounted for.
In plain terms: The paper that named the hard problem: why explaining every brain mechanism might still not explain what it is like to be you.
The full solution space — physicalist, dualist, representationalist — with the explanatory-gap arguments assessed.
In plain terms: The balanced survey of every serious view on whether a finished neuroscience would finish the job.
The alleged residue itself — knowledge and conceivability arguments for and against its irreducibility.
In plain terms: A close look at the thing said to be left over — the redness of red — and the famous thought experiments about it.
Background: Hard problem of consciousness · Neural correlates of consciousness
25. Is there a principled boundary between chemistry and physics?
The boundary examined from chemistry's side: molecular structure, bonding, and the limits of derivation from quantum mechanics.
In plain terms: Chemistry's philosophers on whether their subject has its own floor, or stands on physics all the way down.
The conceptual resources for a principled boundary: novelty, autonomy, and downward constraint.
In plain terms: What it would even mean for chemistry to be genuinely its own science rather than applied physics.
The standard argument-form for autonomy of a special science, applied here at the chemistry–physics seam.
In plain terms: The reusable argument that a science earns independence when its categories cut across physics' own.
Background: Quantum chemistry · Reductionism
26. When does a correlation license an intervention?
Causal inference in statistics: an overview
The do-calculus: exact graphical conditions under which observational correlations identify interventional effects.
In plain terms: The modern answer, free from its author: a calculus that says precisely when seeing licenses doing.
The interventionist analysis of causation underwriting the question's very terms.
In plain terms: The philosophical foundation: to call something a cause just is to say what intervening on it would change.
Structural equations and graphs — the machinery connecting correlation, confounding, and intervention.
In plain terms: The toolkit itself, explained: how arrows and equations encode which correlations can be acted on.
Background: Causal inference · Randomized controlled trial
27. Is the concept of species dispensable?
The concept's rivals — biological, phylogenetic, ecological — and eliminativist and pluralist verdicts on the category.
In plain terms: The full scholarly hearing on whether 'species' names anything nature respects, including the case for retiring it.
The standard for dispensability: what work a kind term must do, and homeostatic-cluster alternatives.
In plain terms: The general question behind this one — when is a category a discovery about the world rather than a filing convenience?
Situates the species debate within biological practice — taxonomy's aims and what eliminating the rank would cost.
In plain terms: What biologists actually need the word for, and what would break — or wouldn't — if it were dropped.
Background: Species problem · Species
28. Can the second law of thermodynamics be derived, or must it be assumed?
Boltzmann's approach to statistical mechanics
The derivation's honest form: typicality arguments deliver the second law given a low-entropy initial condition.
In plain terms: The clearest free statement of what can be proved — disorder wins by counting — and of the one assumption that must be bought.
Science of chaos or chaos in science?
Defends the Boltzmannian derivation against reversibility and recurrence objections; isolates the past state as sole posit.
In plain terms: A pugnacious defence of the derivation, meeting every classic objection and pointing at the single unproved input.
Thermodynamic asymmetry in time
Adjudicates derivation versus postulation, including the Past Hypothesis's status as assumed law or explicandum.
In plain terms: The referee's summary: how much of the second law is theorem, and how much is a fact about how the universe began.
Background: Second law of thermodynamics · H-theorem
29. What, precisely, does a probability in physics measure?
Interpretations of probability
The candidate referents — frequencies, propensities, credences, typicality — with adequacy criteria for physics.
In plain terms: The definitive tour of what a physical probability could possibly be measuring, and the trouble with each answer.
Objective chance's credentials in deterministic and indeterministic physics — what the number attaches to.
In plain terms: Whether the world itself contains chances, or only patterns we quantify — the question's metaphysical half.
Self-locating uncertainty and the origin of probability in Everettian quantum mechanics
A live derivation programme: Born-rule weights as rational self-locating credences in branching worlds.
In plain terms: A modern attempt to earn quantum probabilities from first principles — what the numbers measure if every outcome happens.
Background: Probability interpretations · Propensity probability
30. If you could establish exactly one currently open scientific question, which would most change the rest of science, and why?
The canonical modern exercise in selecting single questions of maximal consequence, with official problem statements.
In plain terms: The famous list built by asking exactly this question of mathematics — seven problems chosen for how much would follow.
A curated, argued inventory of physics' open problems — raw material for judging leverage across the sciences.
In plain terms: A free, opinionated catalogue of what physics does not know, ideal for weighing which ignorance costs the most.
What 'most change the rest of science' could mean: problem-solving, truthlikeness, and knowledge-growth measures of progress.
In plain terms: The conceptual yardstick the question presupposes — what it is for one answer to advance science more than another.
Background: List of unsolved problems in physics · Hilbert's problems