Do you have any examples from the spirits book in mind when you make this claim? I think the philosophy is much more expansive than would be found through fraud unless the mediums were coached, cribbing from a pre-existing source or the entire thing was faked by the spiritists themselves.
As I typed this I knew you would ask that. LOL!! :) OK, my shot at it. There were four in particular through the Introduction, Prolegomena and Chapter II. One pertained to the structure of our physical realm and the elements in particular:
Oxygen, hydrogen, nitrogen, carbon, and all the other masses that we see as elements are merely variations of one primordial substance. As we have found it impossible to arrive at this elemental matter other than as an intellectual deduction, they appear to be elementary. We may therefore continue to regard them as such for now.
This is not actually true - because the quarks which emerge from the quantum froth inside M-theory, do so as independent flavors of energy and not substance - and do not emerge from one primordial substance either. In addition, we can arrive at these elements by means other than an 'intellectual deduction'. We can actually make elements in a fusion reactor. So that also is not true. But in 1860 - we did not have that knowledge.
Finally, the sentence is ambiguously worded such that it can never be held to real account. One can always retort "Well that is what I meant by 'substance' " - something which is not the method/ethic of a higher being. It is like arguing with your 16 year old daughter trying to hide going on a date. A solid wall of neither truth nor lies - is in its entirety a lie.
Something the being in The Spirits' Book avoided almost for the entire text, and that is:
Speak not often, but when you speak,
1. Say what you mean
2. Mean what you say
3. Speak the whole truth, not part
4. Be precise & clear
5. Do not oversimplify nor talk-down to
6. Add value with your words
7. Never seek to dazzle, equivocate nor increase confusion
8. Be accountable.
These are the ethical traits of communication for a higher spiritual being. They are almost the secret handshake if you will.
Then there was the 'proof of God' in Chapter I.
7. Is the frst cause of creation found in the essential properties of matter?
“Then what would be the cause of these properties? There must always be a frst cause.”
To believe in God, simply observe the works of creation. The universe exists, therefore there is a cause. Doubting the existence of God would be to deny that every effect has a cause, and to presuppose the idea that something could be created from nothing.
This is a weak argument from ergodicity. I exist, therefore God exists. God being the first cause. It is not an argument I would expect from a being who has lived in a realm of wisdom for hundreds or thousands of years. It is more what I get from second year Sunday School philosophers or TwitterOthodoxy.
Overall the response from the spirits, just was not that good.