Philosophers cannot agree on whether mathematical objects exist or are pure fictions
Philosophers cannot agree on whether mathematical objects exist or are pure fictions
mathematicians agree to a remarkable degree on whether a statement is true or false, but they cannot agree on what exactly the statement is about.
Was mathematics discovered by humans, or did we invent it?
Before proving a new theorem, therefore, a mathematician needs to watch the play unfold.
This gives the process of doing mathematics three stages: invention, discovery and proof.
a group of mathematicians and philosophers began to wonder what holds up this heavy pyramid of mathematics.
Some mathematicians hoped to solve the foundational crisis by producing a relatively simple collection of axioms from which all mathematical truths can be derived.
Gödel showed that any reasonable candidate system of axioms will be incomplete: mathematical statements exist that the system can neither prove nor disprove.
discovery of a system of basic axioms, known as Zermelo-Fraenkel set theory, from which one can derive most of the interesting and relevant mathematics.
mathematical knowledge is cumulative. Old theories can be neglected, but they are rarely invalidated
Christian Goldbach hypothesized that every even number greater than 2 is the sum of two primes.
this evidence is not enough for mathematicians to declare Goldbach's conjecture correct.
The Goldbach conjecture illustrates a crucial distinction between the discovery stage of mathematics and the proof stage.
math feels both invented and discovered.
The process of mathematics therefore seems to require that mathematical objects be simultaneously viewed as real and invented
Mathematical realism is the philosophical position that seems to hold during the discovery stage: the objects of mathematical study—from circles and prime numbers to matrices and manifolds—are real and exist independently of human minds.
This explains why people across temporal, geographical and cultural differences generally agree about mathematical facts—they are all referencing the same fixed objects.
That is the difficulty with realism—it fails to explain how we know facts about abstract mathematical objects.
If math is simply made up, how can it be such a necessary part of science?
the burden of scientific description is placed exclusively on mathematics, which distinguishes it from other games or fictions.
mathematicians are incredibly effective at producing disciplinary consensus.