My Presuppositions
Presuppositions are the foundational assumptions that are taken for granted in thought, discourse, and inquiry. They are the things I must assume before I can reason about anything else.
Presuppositions cannot be empirically proven, because any attempt to prove them would already depend on them. They are instead rationally motivated: chosen because they make experience and reasoning possible, and because they allow me to build better models that more accurately predict the world around me. Any attempt to justify them further runs into the Münchhausen trilemma: every chain of justification must end in an infinite regress, a circle, or a brute assumption. I choose to make my assumptions explicit.
All of my positions should be read in relation to these presuppositions.
Existence
- I exist.
Self-awareness implies existence (Descartes' cogito). I can find no way to make sense of the proposition that there is no thinker. Even this, however, I hold with the caution described under Certainty. - An external reality exists.
There is a world independent of my perception, and it is the origin of most of my sense data. This cannot be demonstrated against solipsism, but it is the simplest model that accounts for the consistency and independence of experience. - The universe operates according to consistent principles.
The regularities of nature are stable across time and place. These principles are captured, to the best of our present ability, by the laws of physics. Without this assumption, induction and prediction would be impossible.
Epistemology
- Empirical evidence is epistemically privileged.
Observation, testable prediction, and repeatability are the most reliable means of acquiring knowledge. See the Empiricist principle. - Reason and critical thinking are valid tools.
Deductive, inductive, and abductive reasoning are necessary to interpret experience and to make decisions. They are fallible, but there is no better alternative. - Knowledge is provisional and fallible.
All beliefs are open to revision given new evidence or better reasoning (Fallibilism). - There is a distinction between belief and knowledge.
A belief requires justification before it can be considered knowledge, and even then it is only ever provisionally held. - The burden of proof lies with the claimant.
A claim asserted without evidence may be dismissed without evidence (Hitchens' Razor), and extraordinary claims require extraordinary evidence (Sagan Standard). See Burden of proof.
Laws of logic
- The laws of logic are abstract but necessary. They are not physical entities, but they are presupposed in all thought, communication, and scientific inquiry.
- The laws of logic are not empirically derived. They are a priori: assumed as a precondition for making sense of experience at all.
- The laws of logic are compatible with naturalism. They may be understood as features of human cognition evolved for survival and reliable prediction, or as formal constraints on coherent thought. Neither reading requires a supernatural lawgiver (see Transcendental Argument).
- The laws of logic are discovered, not invented, though their formal expression is a human activity.
- I hold the following laws to be valid:
- Law of Identity
A is A.
Each thing is identical to itself.
→ Assumes stable referents in discourse and thought. - Law of Non-Contradiction
¬(A ∧ ¬A).
A proposition cannot be both true and false at the same time and in the same sense.
→ Makes coherent reasoning possible. - Law of Excluded Middle
A ∨ ¬A.
A proposition is either true or false; there is no third option.
→ Foundational to bivalent logic. I note that some formal systems (intuitionistic and many-valued logics) relax this law, but for ordinary reasoning about the world I retain it.