well as his generally recognized personal character, possesses a trustworthiness above every doubt." Yet in the course of your argument you so oppose the authority of these men, and manifest such implied doubts as to the trustworthiness of their testimony, that you substantially deny them these attributes. Please note, in this connection, the one instance, at least, where you impute to them absolutely unscientific action. In the case of the revolutions of the magnetic needle which Slade professedly produced by the motions of his hands, you say: "The phenomena themselves are exactly like those which any man might perform who was provided with a powerful magnet. And you will not deny that the value of these phenomena as an argument in the demonstration, depends entirely upon the trustworthiness of the actor, i. e., the medium. And it is quite intelligible that these distinguished scientists, who observed the remarkable phenomena, especially the move. ment of the Ampère or Weber molecular currents, were completely convinced. A practical jurist would probably have been much less astonished, since he is much less accustomed to believe in the honesty of the things he investigates. He would hardly have failed to investigate the coat sleeves of the medium, while the latter was demonstrating his magnetic powers.

I should have been glad to have you state the omission of this proof as a fact rather than as a mere surmise of your own: for I must admit that it is very hard for me to believe that there was such a remarkable omission of the first principles of scientific investigation on the part of authorities of the first rank when they were conducting such an apparently important examination. I can think the theory presumable from the arguments you present. For the more these distinguished scientists were astonished at the remarkable phenomena they witnessed, all the more because they were distinguished as scientists, they must have felt compelled to thoroughly satisfy themselves that these things were not the result of deception, even though they were generally persuaded of Slade's personal trustworthiness. Otherwise there could not have been, on any trustworthy basis, any confidence in Slade's honesty, especially since the experiment in question was the first that Zöllner and his friends had seen Slade perform.

But your principal objection to my confidence in and claim for these scientific authorities, and the consequent trustworthiness of their testimony, rests upon your assumption that the spiritistic phenomena are not natural phenomena: and that therefore authorities in natural science cannot be claimed to have authority in this department. You support your assumption by this particular statement: "All methods of investigation in natural science depend upon the presumption of inflexible law-abiding character in the phenomena: a presumption which includes this other one, that wherever the same conditions obtain, like results are sure to follow. The scientist therefore continues his observations with unwavering faith in the genuineness of the objects he is considering. Nature cannot deceive him. Neither fraud nor chance has control there." But when you add: "Now you must admit that in the realm of spiritistic phenomena nobody can assert any such law-abiding character. On the other hand, the most prominent characteristics of these phenomena lie athwart the line of natural law," you make the direct assumption that these spiritistic manifestations are not natural phenomena, and that "the observations of the spiritistic and natural have been mutually contradictory." I admit that many things seem to support your assumption: but the reality of the phenomena being admitted, it follows that your premise declaring the absolute conformity of nature must be contradictory. I deny this contradiction, and you assert it and on this disagreement rests chiefly our difference of opinion in the apprehension of the spiritistic phenomena. You will therefore permit me to enter upon a further statement of this manifestly fundamental point in the discussion.

I believe that the above assumption is a mere assumption, unproved, and incapable of proof. For at the outset you will bear in mind that the law of causality is by no means a natural law that is, it is not a law resting upon or drawn from our knowledge of Nature, but a law of the mind which we attribute to Nature and natural phenomena. Hume was perfectly right, I think, when he states that experience never declares that anything which takes place is necessarily associated in its taking place with anything else, as the law of causality assumes and demands. He combats therefore from his purely

empirical standpoint the validity of the law of causality. And he is right, on the simple ground that "Necessity" as such can neither be seen nor heard, tasted nor felt, and is consequently per se not perceptible nor discoverable. There is no such thing as necessity, except in our mental constitution, or as deduced from our mental constitution. If, therefore, we assert the law of causality as a natural law, and extend its validity to Nature and natural phenomena, we are only authorized to do this for this reason, that we find ourselves from within compelled to admit that all phenomena rest upon powers through whose efficiency the phenomena are produced. Since the law of causality may be formally constructed, it is of no importance to us just now, whether or no it is derived from the nature of mind (the limitations of our being) in due formality, clear and well-defined, and therefore established as a law. It suffices for the consideration and decision of our point at issue, if it is generally admitted that the law of causality cannot be proven from or by means of experience, (including science). For then it follows indisputably, as it seems to me, that this scientific assumption is a mere assumption.

But even if we admit the law of causality as a general law having its foundation in nature, I think that it does not by any means follow that the course of nature and natural phenomena is dominated over by an absolute rule of conformity to law. But this absolute conformity to law is the basis on which your argument rests. For if such absolute conformity to law rules over all nature, then only can it be assumed that the spiritistic phenomena are not natural phenomena. But another conclusion will now follow, and that a conclusion of greater importance and weight. We shall have incontestably put before us the alternative either simply to deny man's free will, or to declare that the results which flow from the exercise of free will are not natural phenomena. Since it can not reasonably be supposed—at least I do not know of any phi losophy that does suppose it-that man does not belong to the natural world, (that is, that he is not a natural being, but either wholly or in part an unnatural or supernatural being), we shall have left only the first alternative. But the acceptance of such a theory brings us to the denial of all morality: a

conclusion which a thinker as keen and logical as yourself

cannot escape.

I have heretofore (Gott und die Natur, etc.), endeavored to show that no force, requiring absolute conformity to law, flows out upon Nature from the law of cause and effect, and that therefore no such force exists. Since the final result of our discussion depends so largely upon the outcome of this endeavor, permit me here to repeat the main points of my argument.

The law of causality demands only this, that everything that occurs must be considered as the result of a cause, i. e., the effect of a power or active existence. This requirement neither interferes with spiritistic manifestations, nor the freewill actions of men. These last are the exercise of our own powers set into motion through a determination of the will. It is still a question, how, and through what means, these forces are awakened to activity: but no spiritist even has presumed that they are awakened without the exercise of definite causes. It is only when we further recognize the fact that the general government of the law of causality involves a like general, inviolable, unbroken chain of causes and effects-a causal nexus, in which every thing that happens proceeds necessarily from the constitution, conditions, accompaniments, and relationships of active forces,-that we fail to perceive any conflict. between spiritistic manifestations, human actions, and natural phenomena. This concept is like a mathematical axiom of such widely recognized validity, that any person, who should set himself against it, would be read at once out of the list of scientists and investigators in the realm of Nature. And still this is, I think, only another mere hypothesis. It rests on the fact professedly demonstrated by natural science, that absolutely nothing in nature that exercises power is self-active. All forces are only conditionally active, since they are powers whose activity and conditions of working are dependent upon or limited by other powers which work in or through them. And it is only because their activity is thus the result of other forces working in and through them, that the causal nexus exists as the chain of cause and effect, and is established thereby. We grant that the natural powers discovered by

natural science are undoubtedly conditional powers, and it is undoubtedly sure, beyond the fear of successful contradiction, that the causes of natural phenomena thus far actually discovered, are only the proximate causes, the manifestations of the immediately effective causes; while the remoter causes, that is, those through which these next in their turn are conditioned and limited, remain, thus far at least, in regions beyond the reach of our investigation and acquaintanceship. So it is only by analogical inference, therefore, after all that we conclude that absolutely all the powers which work in nature are conditioned and of course nothing can be counted certain which is only an inference from an hypothesis.

But even if we assent to this conclusion it by no means follows as a result that one unchangeable conformity to law obtains in Nature with absolute generality. Such a conformity to law involves an absolute, inviolable necessity, which reaches every action in every relationship. For a thing is only conformable to a law, when it is limited by the law in every possible relationship. Unchangeable conformity to law on the part of all natural phenomena could only take place if it were an established fact that no force in nature should be able to exercise any powers except those which possessed exactly defined, and absolutely limited effects; and, contrariwise, that every natural power should be necessarily active, and necessitated to exercise its powers. But this is by no means true. On the contrary the facts contradict the assumption. The merest glance at the commonest phenomena of nature shows that there are no two pieces of the same stone exactly alike, no two exactly similar crystals, no two offspring of the same parents exactly alike, no two eggs of the same hen exactly alike, and no two leaves of the same tree, even, exactly correspond. Even in those cases where we must acknowledge that. the same powers were in operation, and the surroundings and conditions of the phenomena were the same, the results differ. Natural science admits these undeniable facts. It seeks to preserve its axiom through the further proposition that "the same conditions never anywhere exactly return, and the law does not demand that they should." (Theo. Fechner.) But this proposition, too, is a mere hypothesis. For it is quite im