I think that Engels was overall quite
perspicacious in the passage cited, one of my favorites from Engels.
The 4th dimension was quite a fad in the late
19th century, in addition to its strictly
mathematical function. I'm not sure whether
anyone dreamed of applying it to natural reality,
but
Engels was, course, quite right to debunk belief
in ghosts and mediums. In fact there were some
political reasons behind this. At the time that
Engels wrote this, spiritualism was quite popular
within the IWMA, especially in the US and UK.
In the US, one of the leading figures in the IWMA,
Victo
