What exists, and in what sense — universals, causation, time, identity, and whether free will survives any of the answers.
11 topics · 16 curated works
No prior grounding assumed.
A Philosophical Essay on Probabilities
Pierre-Simon Laplace · 1814
An intelligence that knew every force and position in the universe at one instant could calculate its entire future and past, so what looks like…
Assumes you know the vocabulary.
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Aristotle · 350 BCE
Sorts everything that exists into ten highest kinds headed by substance, and argues substance alone can exist independently while properties exist…
+1 more at this level
Primary sources and full treatments.
Metaphysics
Aristotle · 350 BCE
Investigates being qua being, what it is for anything at all to exist, and argues that substance, especially form, is the primary sense in which…
+12 more at this level
12 of 16 works
Pierre-Simon Laplace
An intelligence that knew every force and position in the universe at one instant could calculate its entire future and past, so what looks like chance is only a measure of our own ignorance in a fully determined world.
link checked 17 Sept 2026Aristotle
Sorts everything that exists into ten highest kinds headed by substance, and argues substance alone can exist independently while properties exist only by inhering in it.
about 60 minutes to readlink checked 17 Sept 2026D. M. Armstrong
Defends a moderate realism on which universals exist only in the particulars that instantiate them, surveying and rejecting nominalist alternatives in turn.
Aristotle
Investigates being qua being, what it is for anything at all to exist, and argues that substance, especially form, is the primary sense in which anything is said to be.
link checked 17 Sept 2026Georg Wilhelm Friedrich Hegel
Argues that the categories of thought generate one another by their own contradictions, so logic is not a set of rules applied to content but the self-development of what there is.
link checked 17 Sept 2026J. M. E. McTaggart
Distinguishes the A-series of past, present and future from the B-series of earlier and later, and argues that time requires the A-series, which generates a contradiction, so time itself is unreal.
link checked 17 Sept 2026C. Lloyd Morgan
Sets out emergent evolution as a middle path between mechanism and vitalism, arguing that genuinely new kinds of relatedness, from life out of matter to mind out of life, appear at each level without any added substance.
link checked 17 Sept 2026C. D. Broad
Sets out emergent evolution — the view that higher-level properties like mentality are genuinely novel and not deducible even in principle from the arrangement of their lower-level parts.
link failing as of 17 Sept 2026Frank P. Ramsey
Argues the traditional distinction between particulars and universals is not a fundamental division in reality but an artefact of subject-predicate grammar, since the same fact can be described either way.
link checked 17 Sept 2026Willard Van Orman Quine
A theory is committed only to the entities its bound variables must range over to make its sentences true, giving a test for what a theory says exists that does not depend on how its words sound.
link checked 17 Sept 2026Saul Kripke
Sets out a formal semantics for modal logic in which necessity and possibility are evaluated relative to a set of possible worlds linked by an accessibility relation, giving later metaphysical talk of possible worlds its formal backbone.
link checked 17 Sept 2026Harry Frankfurt
Constructs cases where an agent could not have done otherwise yet is still clearly responsible, arguing that moral responsibility does not require the ability to do otherwise as the principle of alternate possibilities claims.
link checked 17 Sept 2026