While admitting all this, however, one must also admit that it is easy to go too far in the opposite direction, and reject evidence which depends upon the senses simply _because_ they depend upon them. This, I think, is invalid reasoning. No one would be more willing than I to admit their fallibility and untrustworthiness--especially when we are dealing with conditions and phenomena where mal-observation is possible; but I do not think that any negative conclusion can be drawn from this. The case is still an open one; nothing is _proved_, one way or the other, and, in such work as ours, proof--and not mere conjecture--must be forthcoming. Very true it is that proof of the sort desired is often impossible; but it is obtained sometimes. If a medium be caught masquerading in a white muslin "robe" and a mask, we are doubtless within our rights in saying that the medium has been _proved_ a fraud. But failure to detect such trickery does not prove the phenomena genuine. That would depend upon other considerations, and would only raise a _presumption_ in favour of their authenticity. In such a case, "proof" is largely a question of relative probability, and can be obtained only by making the probability in favour of the reality of the phenomena so strong that the negative aspect is rendered logically unsound by the sheer weight of evidence against it. These trite remarks were nevertheless rendered necessary because of the enormous amount of misunderstanding which exists in connection with these phenomena, and of the general methods and objects of psychic research. The papers that have already been published on the question of hallucination in relation to the physical phenomena should do much to clear away many of these misconceptions, for in them we find (i) a willingness to treat the phenomena seriously; (ii) an admission that the witnesses described what they thought they saw; and (iii) a certain amount of evidence advanced to show that the alleged phenomena were in reality hallucinatory in character, while appearing to be external physical realities to the onlookers. Let us now examine the evidence advanced, and see in how far it is conclusive of the theory entertained--the hypothesis of hallucination. As both Count Solovovo and Miss Johnson have concentrated their attention upon the phenomena occurring in the presence of D. D. Home, I shall do so likewise in the first part of this chapter. As briefly as possible, I shall review their papers, before passing on to more general remarks--remarks which it is the object of this paper to bring into prominence. Count Solovovo thinks that it is evidence in favour of the hallucination theory that: "A flower or other small object is seen to move; one person present will see a luminous cloud hovering over it, another will detect a nebulous-looking hand, whilst others will see nothing but the moving flower."[27]