Such being the case, we may fairly conclude that all these old-standing "mysteries" are now merged in the one mystery of existence. And deeper than this it is manifestly impossible that they can be merged; for it is manifestly impossible that Existence in the abstract can ever admit of what we call explanation. Hence we can clearly see that, in a scientific sense, there must always remain a final mystery of things. But although we can thus see that, from the very meaning of what we call explanation, it follows that at the base of all our explanations there must lie a great Inexplicable, I think that the mystery of Existence in the abstract may be rendered less appalling if we reflect that, as opposed to Existence, there is only one logical alternative--Non-existence. Supposing, then, our physical explanations to have reached their highest limits by resolving all modes of Existence into one mode--force, matter, life, and mind, being shown but different manifestations of the same Infinite Existence--the final mystery of things would then become resolved into the simple question, Why is there Existence?--Why is there not Nothing? Let us then first ask, What is "Nothing"? Is it a mere word, which presents no meaning as corresponding to any objective reality, or has the word a meaning notwithstanding its being an inconceivable one? Or, otherwise phrased, is Nothing possible or impossible? Now, although in ordinary conversation it is generally taken for granted that Nothing is possible, there is certainly no more ground for this supposition than there is for its converse--viz., that Nothing is merely a word which signifies the negation of possibility. For analysis will show that the choice between these two counter-suppositions can only be made in the presence of knowledge which is necessarily absent--the knowledge whether the universe of Existence is finite or infinite. If the universe as a whole is finite, the word Nothing would stand as a symbol to denote an unthinkable blank of which a finite universe is the content. And forasmuch as Something and Nothing would then become actual, as distinguished from nominal correlatives, we could have no guarantee that, in an absolute or transcendental sense, it may not be possible, although it is inconceivable, for Something to become Nothing or Nothing Something. Hence, if Existence is finite, No-existence becomes possible; and the doctrine of the indestructibility of Existence becomes, for aught that we can tell, of a merely relative signification. But, on the other hand, if Existence is infinite, No-existence becomes impossible; and the doctrine of the indestructibility of Existence becomes, in a logical sense, of an absolute signification. For it is manifest that if the universe of Existence is without end in space and time, the possibility of No-existence is of necessity excluded, and the word "Nothing" thus becomes a mere negation of possibility.[47]