This is directly bitten from something the British mystic/magus/a million other weird things Aleister Crowley wrote. It relates to using occult/magickal techniques to find spiritual truths, an expanded sense of awareness (etc.), techniques such as dramatic ritual and vocal evocation of various entities. The 'reality' of these things is not really the issue, but rather the fact they are in a category in which things can't feasibly exist, yet they can be perceived at certain times (reliably, but only for those wise/foolhardy enough to try) and interacted with.
Put simply, it's not known whether these 'entities' are something external or 'other' or emanations from inside people's own nervous systems (or indeed, something in between--something like Jung's collective unconscious, for instance). The fact is, they can be contacted with certain techniques and employed to assist people in various workings of inner will (manifesting things you want to occur, setting currents into motion to help them occur). A strict definition of what they 'are' is also less important than what can be reliably done with the techniques.
It's obviously very strange territory, folks, but it's interesting stuff for me, anyways. The occult almost represents the ultimate syncretic religion, everything fused together in a grand unified theory, with the final element being that of the individual, and all the weird divinity within each one. Anyways, the only other stray, necessary comment is that the entire point of magick or religions (or organizations) that employ the same techniques is to experiment with it as a scientist would, and report back.
blah blah yadda blah, enough yammerin'.
Here's the full original quote:
"We place no reliance on virgin or pidgeon.
Our method is science, our aim is religion."