- Ludwig Wittgenstein (Wikipedia)
Ludwig Josef Johann Wittgenstein (/ˈvɪtɡənʃtaɪn, -staɪn/ VIT-gən-s(h)tyne; German: [ˈluːtvɪç ˈjoːzɛf ‘joːhan ˈvɪtɡn̩ʃtaɪn]; 26 April 1889 – 29 April 1951) was an Austrian philosopher who worked primarily in logic, the philosophy of mathematics, the philosophy of mind, and the philosophy of language. He is considered by some to be the greatest philosopher of the 20th century.
- Guadalupian (Wikipedia)
The Guadalupian is the second and middle series/epoch of the Permian. The Guadalupian was preceded by the Cisuralian and followed by the Lopingian. It is named after the Guadalupe Mountains of New Mexico and Texas, and dates between 272.95 ± 0.5 – 259.1 ± 0.4 Mya. The series saw the rise of the therapsids, a minor extinction event called Olson’s Extinction and a significant mass extinction called the end-Capitanian extinction event. The Guadalupian was previously known as the Middle Permian.