Frege's logico-mathematical and philosophical speculations were not historically isolated phenomena that arose completely de novo, as it were like fulgurations of genius out of a conceptually unclouded sky. They were more like nodal points in a long series of speculative endeavours that began with people like Raymon Lull in the Middle Ages,¹ continued through Descartes,² Kircher,³ Böhme⁴ and Leibniz,⁵ that drew on the thoughts of people like Bruno⁶ and Pascal,⁷ Gergonne⁸ and Hobbes,⁹ Gregoire¹⁰ and Bolzano,¹¹ and in turn constituted the basis of much contemporary thought — the works of Russel1¹² and Carnap,¹³ Husserl¹⁴ and Wittgenstein,¹⁵ Church,¹⁶ Strawson¹⁷ and Quine¹⁸ immediately come to mind.