ing their specific gravity possess a mechanism for raising themselves to the top of the water, or lowering themselves to the bottom at will. They use this not only in the abnormal circumstances of their being under microscopical observation, but at all times, as may be known by our being always able to find some specimens with air-bladders at the top of the water in which they live."

If what has been already advanced has failed to convince the reader of the hopelessness of attempting to explain instinct as a mode of conscious deliberation, he must admit that the following considerations are conclusive. It is most certain that deliberation and conscious reflection can only take account of such data as are consciously perceived; if, then, it can be shown that data absolutely indispensable for the arrival at a just conclusion cannot by any possibility have been known consciously, the result can no longer be held as having had its source in conscious deliberation. It is admitted that the only way in which consciousness can arrive at a knowledge of exterior facts is by way of an impression made upon the senses. We must, therefore, prove that a knowledge of the facts indispensable for arrival at a just conclusion could not have been thus

acquired. This may be done as follows:for, Firstly, the facts in question lie in the future, and the present gives no ground for conjecturing the time and manner of their subsequent development.

Secondly, they are manifestly debarred from the category of perceptions perceived through the senses, inasmuch as no information can be derived concerning them except through experience of similar occurrences in time past, and such experience is plainly out of the question.

It would not affect the argument if, as I think likely, it were to turn out, with the advance of our physiological knowledge, that all the examples of the first case that I am about to

1 "Dieser Beweis ist dadurch zu führen; erstens dass die betreffenden Thatsachen in der Zukunft liegen, und dem Verstande die Anhaltepunkte fehlen, um ihr zukünftiges Eintreten aus den gegenwärtigen Verhältnissen zu erschliessen; zweitens, dass die betreffenden Thatsachen augenscheinlich der sinnlichen Wahrnehmung verschlossen liegen, weil nur die Erfahrung früherer Fälle über sie belehren kann, und diese laut der Beobachtung ausgeschlossen ist. Es würde für unsere Interessen keinen Unterschied machen, wenn, was ich wahrscheinlich halte, bei fortschreitender physiologischer Erkenntniss alle jetzt für den ersten Fall anzuführenden Beispiele sich als solche des zweiten Falls ausweisen sollten, wie dies unleugbar bei vielen früher gebrauchten Beispielen schon geschehen ist; denn ein apriorisches Wissen ohne jeden sinnlichen Anstoss ist wohl kaum wunderbarer zu nennen, als ein Wissen, welches zwar bei Gelegenheit gewisser sinnlicher Wahrnehmung zu Tage tritt, aber mit diesen nur durch eine solche Kette von Schlüssen und angewandten Kenntnissen in Verbindung stehend gedacht werden könnte, dass deren Möglichkeit bei dem Zustande der Fähigkeiten und Bildung der betreffenden Thiere entschieden geleugnet werden muss."-Philosophy of the Unconscious, 3d ed., p. 85.

adduce reduce themselves to examples of the second, as must be admitted to have already happened in respect of many that I have adduced hitherto. For it is hardly more difficult to conceive of à priori knowledge, disconnected from any impression made upon the senses, than of knowledge which, it is true, does at the present day manifest itself upon the occasion of certain general perceptions, but which can only be supposed to be connected with these by means of such a chain of inferences and judiciously applied knowledge as cannot be believed to exist when we have regard to the capacity and organisation of the animal we may be considering.

An example of the first case is supplied by the larva of the stag-beetle in its endeavour to make itself a convenient hole in which to become a chrysalis. The female larva digs a hole exactly her own size, but the male makes one as long again as himself, so as to allow for the growth of his horns, which will be about the same length as his body. A knowledge of this circumstance is indispensable if the result achieved is to be considered as due to reflection, yet the actual present of the larva affords it no ground for conjecturing beforehand the condition in which it will presently find itself.

As regards the second case, ferrets and buzzards fall forthwith upon blind worms or other non-poisonous snakes, and devour them then and there. But they exhibit the greatest caution in laying hold of adders, even though they have never before seen one, and will endeavour first to bruise their heads, so as to avoid being bitten. As there is nothing in any other respect alarming in the adder, a conscious knowledge of the danger of its bite is indispensable, if the conduct above described is to be referred to conscious deliberation. But this could only have been acquired through experience, and the possibility of such experience may be controlled in the case of animals that have been kept in captivity from their youth up, so that the knowledge displayed can be ascertained to be independent of experience. On the other hand, both the above illustrations afford evidence of an unconscious perception of the facts, and prove the existence of a direct knowledge underivable from any sensual impression or from consciousness.

This has always been recognised,1 and has

1 "Man hat dieselbe jederzeit anerkannt und mit den Worten Vorgefühl oder Ahnung bezeichnet; indess beziehen sich diese Wörte einerseits nur auf zukünftiges, nicht auf gegenwärtiges, räumlich getrenntes Unwahrnehmbares, anderseits bezeichnen sie nur die leise, dumpfe, unbestimmte Resonanz des Bewustseins mit dem unfehlbar betsimmten

been described under the words "presentiment" or "foreboding." These words, however, refer, on the one hand, only to an unknowable in the future, separated from us by space, and not to one that is actually present; on the other hand, they denote only the faint, dull, indefinite echo returned by consciousness to an invariably distinct state of unconscious knowledge. Hence the word "presentiment," which carries with it an idea of faintness and indistinctness, while, however, it may be easily seen that sentiment destitute of all, even unconscious, ideas can have no influence upon the result, for knowledge can only follow upon an idea. A A presentiment that sounds in consonance with our consciousness can indeed, under certain circumstances, become tolerably definite, so that in the case of man it can be expressed in thought

Zustande der unbewussten Erkenntniss. Daher das Wort Vorgefühl in Rücksicht auf die Dumpfheit und Unbestimmtheit, während doch leicht zu sehen ist, dass das von allen, auch den unbewussten Vorstellungen entblösste Gefühl für das Resultat gar keinen Einfluss haben kann, sondern nur eine Vorstellung, weil diese allein Erkenntniss enthält. Die in Bewusstsein mitklingende Ahnung kann allerdings unter Umständen ziemlich deutlich sein, so dass sie sich beim Menschen in Gedanken und Wort fixiren lässt; doch ist dies auch im Menschen erfahrungsmässig bei den eigenthümlichen Instincten nicht der Fall, vielmehr ist bei diesen die Resonanz der unbewussten Erkenntniss im Bewusstsein meistens so schwach, dass sie sich wirklich nur in begleitenden Gefühlen oder der Stimmung äussert, dass sie einen unendlich kleinen Bruchtheil des Gemeingefühls bildet."-Philosophy of the Unconscious, 3d ed., p. 86.