metaphysicsnoun
met-uh-FIZ-iks
The branch of philosophy concerned with the fundamental nature of reality, existence, space, time, causation, and identity. Metaphysical questions — such as "why is there something rather than nothing?" — lie beyond the reach of empirical testing.
"Science can describe how the universe began, but the metaphysical question of why there is a universe at all remains unanswered."
ethicsnoun
ETH-iks
The branch of philosophy concerned with questions of right and wrong, obligation, and how we ought to live. Ethics deals in normative claims — what should be — rather than descriptive claims about what is, which is science's domain.
"Science can tell us that a drug extends life by three months, but ethics must determine whether the suffering involved makes it worth taking."
normative claimnoun phrase
NOR-muh-tiv klaym
A statement about what ought to be, what is good or bad, or what should be done. Normative claims cannot be verified or falsified by empirical evidence alone, because they involve values, not just facts.
"'We should reduce carbon emissions' is a normative claim — science can inform the debate, but the 'should' is a moral judgment, not a scientific finding."
descriptive claimnoun phrase
dih-SKRIP-tiv klaym
A statement about how things are, based on observation and evidence. Descriptive claims are the proper domain of science. The distinction between descriptive and normative claims is central to understanding what science can and cannot settle.
"'Carbon emissions have risen by 40% since 1850' is a descriptive claim — verifiable by data, and entirely within science's territory."
is-ought problemnoun phrase
iz-awt PROB-lem
David Hume's observation that one cannot logically derive what ought to be from what is — that descriptive facts alone cannot justify moral conclusions. Also called "Hume's guillotine," it marks a fundamental boundary between science and ethics.
"'Evolution favors the strong, therefore we should let the weak perish' commits the is-ought fallacy — natural facts do not determine moral duties."
consciousnessnoun
KON-shus-nes
The state of being aware of and able to think about one's own existence, thoughts, and experiences. Why there is subjective, first-person experience at all — the "hard problem" — is among the deepest questions science has not resolved.
"Neuroscience maps the brain's activity during thought, but explaining why any of that activity feels like something from the inside remains the mystery of consciousness."
hard problem of consciousnessnoun phrase
hard PROB-lem uv KON-shus-nes
The philosophical challenge of explaining why physical brain processes give rise to subjective experience — why there is "something it is like" to be a conscious being. Coined by philosopher David Chalmers, it is considered beyond current scientific explanation.
"The hard problem of consciousness asks not how the brain processes information, but why that processing feels like anything at all."
meaningnoun
MEE-ning
The sense of purpose, significance, or value that people find in their lives and experiences. Questions of meaning — why we are here, what makes a life worthwhile — are not empirical questions and cannot be answered by measurement or experiment.
"Science can describe the mechanics of human existence but cannot tell us whether that existence has meaning — that question belongs to philosophy and lived experience."
teleologynoun
tel-ee-OL-uh-jee
The philosophical study of purpose, ends, or goals in nature or human life. Teleological thinking asks "what is this for?" — a question that science tends to replace with "how does this work?" Modern science is largely non-teleological.
"Aristotle's teleology held that everything in nature had a purpose; Darwin replaced that framework with one in which adaptation has no goal or intention."
free willnoun phrase
free wil
The capacity to make choices that are genuinely one's own and not fully determined by prior causes. Whether free will exists — and what it means for moral responsibility — is a question at the intersection of neuroscience, philosophy, and religion that science alone cannot settle.
"If neuroscience shows that decisions are made before we are conscious of them, does free will exist? The question is philosophical as much as scientific."
scientismnoun
SY-un-tiz-um
The belief that science is the only valid form of knowledge and that all questions — including ethical and metaphysical ones — can in principle be answered by scientific methods. Critics argue that scientism oversteps science's legitimate boundaries.
"Her critics accused her of scientism — of assuming that if something cannot be measured, it is not real or worth considering."
naturalismnoun
NACH-er-ul-iz-um
The philosophical view that everything that exists is part of the natural world and can in principle be explained by natural causes. Naturalism rejects supernatural explanations but does not necessarily claim science answers every question.
"His naturalism led him to believe that consciousness, morality, and meaning must all ultimately be explicable in terms of natural processes."
transcendencenoun
tran-SEN-dens
The state of being or existence beyond the normal or physical level; going beyond ordinary limits. In religion and philosophy, transcendence refers to that which lies beyond the natural world — a realm science, by definition, cannot access.
"Mystics across traditions describe experiences of transcendence — a sense of contact with something beyond the physical — that no brain scan can fully capture."
qualianoun (plural)
KWAH-lee-uh
The subjective, felt qualities of conscious experience — the redness of red, the painfulness of pain, the taste of coffee. Qualia are inherently first-person and are considered by many philosophers to be beyond purely scientific description.
"A complete description of the wavelength of red light tells us nothing about the qualia — the felt experience — of seeing that color."
value pluralismnoun phrase
VAL-yoo PLOOR-ul-iz-um
The view, associated with Isaiah Berlin, that there are many genuine, irreducible human values that can conflict with one another — and that no single value or formula can resolve all moral conflicts. Science cannot adjudicate between competing values.
"Value pluralism holds that freedom and equality are both genuine goods that sometimes cannot both be maximized — a conflict no equation can resolve."
ontologynoun
on-TOL-uh-jee
The branch of philosophy concerned with the nature of being and existence — what kinds of things exist and how they relate to one another. Ontological questions about God, the soul, or the reality of abstract objects lie outside empirical investigation.
"The ontological question of whether numbers truly exist or are merely useful fictions is one that mathematics itself cannot answer."
epistemological humilitynoun phrase
ih-pis-teh-muh-LOJ-ih-kul hyoo-MIL-ih-tee
The intellectual virtue of recognizing the limits of one's own knowledge and the possibility that one's beliefs may be incomplete or mistaken. Epistemological humility is considered essential for honest inquiry, especially at the boundaries of science.
"Good scientists practice epistemological humility — they know what their methods can establish and are honest about what lies beyond their reach."
reductionismnoun
rih-DUK-shun-iz-um
The practice of analyzing complex phenomena by breaking them into simpler, more fundamental components. Critics argue that reductionism loses something when applied to consciousness, art, or meaning — that the whole is genuinely more than the sum of its parts.
"Reductionism can explain the chemistry of love, but many argue it cannot explain what love means to the person experiencing it."
emergencenoun
ih-MUR-jens
The process by which complex systems and patterns arise out of relatively simple interactions, producing properties that cannot be predicted from the components alone. Emergence is sometimes invoked to explain phenomena — such as consciousness — that seem to exceed their physical basis.
"Consciousness may be an emergent property of the brain — something that arises from neural activity but cannot be found in any single neuron."
moral realismnoun phrase
MOR-ul REE-ul-iz-um
The view that moral facts exist objectively and independently of what any individual or culture believes. If moral realism is true, then ethical questions have right answers — though whether science can discover them remains disputed.
"Moral realism holds that 'torturing innocents for fun is wrong' is as objectively true as '2 + 2 = 4' — a claim that challenges purely scientific accounts of value."
moral relativismnoun phrase
MOR-ul REL-uh-tiv-iz-um
The view that moral judgments are not objectively true or false but are relative to individuals, cultures, or historical contexts. Moral relativism denies that there are universal moral facts that science or reason could discover.
"Moral relativism would say that the practice was neither right nor wrong in itself — only right or wrong relative to the norms of a given society."
existential questionnoun phrase
eg-zis-TEN-shul KWES-chun
A question about the fundamental nature and purpose of human existence — why we are here, how we should live, how to face death. Existential questions are among those science cannot resolve because they concern meaning, not mechanism.
"Why do I exist? What should I do with my life? These are existential questions that no laboratory can answer."
demarcation problemnoun phrase
deh-mar-KAY-shun PROB-lem
The philosophical challenge of distinguishing science from non-science or pseudoscience. Various criteria — falsifiability, testability, predictive power — have been proposed, but philosophers of science have found no single, definitive solution.
"The demarcation problem matters practically: where we draw the line between science and non-science affects education, policy, and law."
limits of empiricismnoun phrase
LIM-its uv em-PEER-ih-siz-um
The boundaries of what can be known through sensory experience and observation. Some philosophers argue that logic, mathematics, and ethics reveal truths that go beyond what empirical observation alone can establish.
"The limits of empiricism become clear when we ask whether moral duties are real — no experiment can measure the wrongness of cruelty."
wondernoun
WUN-der
A feeling of amazement and admiration in the face of something unexplained, beautiful, or vast; the emotional and intellectual response to encountering mystery. Wonder is considered by many thinkers to be the proper response to the limits of knowledge rather than frustration.
"Einstein said that the most beautiful thing we can experience is the mysterious — suggesting that wonder, not certainty, is the truest scientific attitude."