英语长难句求助Probably,there is one here who has not in the course

英语长难句求助
Probably,there is one here who has not in the course of the day had occasion to set in motion a complex train of reasoning of the very same king,though differing in degree,as that which a scientific man goes through in tracing the causes of natural phenomena.
小弟的疑问是：has not had occasion.中的had怎么理解；
as that which.goes through in 中的that怎么理解,是作为代词“那种”吗?