a priori
(using reasoning that proceeds) from known causes to imagined effects, eg saying `They've been walking all day so they must be hungry.' (用推理方法)由已知原因推测出结果(如说
'他们走了一整天, 那么他们一定饿了.') Cf 参看 a posteriori.
Apparently what happened was that water collected on these tar pits, and the bigger animals like the elephants ventured out on to the apparently firm surface to drink, and were promptly bogged in the tar.