But presence of mind connects itself with an interesting fact in our grammar about the _present tense_. The present tense, in contrast with past and future tenses, expresses presence of mind, attention to the wonder of the moment, the opportunity of the moment. But it also expresses a wholly different thing, namely, the _eternal_. Some languages have an eternal tense and use it about facts that are not present or past or future. We use the present tense for the eternal. Two and two make four. When? Well, not of course at ten minutes before twelve on the 11th of November, 1918, more than at any other time. We might just as well use the future tense. Two and two always will make four. But by a peculiar accident we have hitched on to one tense the whole body of eternal truth. _Why did we hitch the eternal to the present rather than to the past or to the future?_ Because anything that we really grasp now, as truth or as joy or as beauty, anything that we really comprehend, can be eternally ours. In the physical sense it is so. The electric light that I am now looking at and which might be turned off at any moment, is eternal, for its vibrations are travelling off through space and always will be. The fact that those vibrations are going off through the ether is ever the same. Any present fact, then, so far as we realize its truth or its wonder, is eternally ours. Hence presence of mind is the quality needed in social work to balance the scientific habit which looks for past and future, for what is not present. Investigation and history-taking must always be completed by _appreciation_, the other half of our mental life, which is acutely conscious of the present and therefore can be conscious of eternity.