http://dswarmsikhttkg7jgsoyfiqpj3ighupfrvuz5ri3lu5q2dlqyrpgk7ad.onion/notes/frege-ancestral.html
\end{align*} Such a sequence is simply a list, it does not constitute a definition of a concept (e.g., natural number ) that applies to all and only the numbers defined in the sequence. Also, this sequence cannot show that every natural number has a successor. — Frege defined the concept of natural number by first defined a 2-place relation \(R\), the relation is a parent of.