Full Idea
What is thinkable is possible too.
Gist of Idea
What is thinkable is possible
Source
Ludwig Wittgenstein (Tractatus Logico-Philosophicus [1921], 3.02)
Book Reference
Wittgenstein,Ludwig: 'Tractatus Logico-Philosophicus (Pears)', ed/tr. Pears,D. /McGuinness,B. [RKP 1961], p.11
A Reaction
[Plucked from a context!] The modern tide has turned against this idea. The more clearly you understand the facts, the more restricted the possibilities become. If you think the impossible is possible, it is because you are bad at thinking.