Sentence:  The first thing to bear in mind (especially if we ourselves belong to the clerico-academic-scientific type, the officially and conventionally “correct” type, “the deadly respectable” type, for which to ignore others is a <WSD>besetting</WSD> temptation) is that nothing can be more stupid than to bar out phenomena from our notice, merely because we are incapable of taking part in anything like them ourselves. 
Meaning of the word marked with <WSD> tags:  Deeply rooted; persistent.