Yet, it will be objected, it is a fact that we all form previsions, and that without them we should neither be able to cook an egg nor to take one step out of doors. That is quite true, but those alleged previsions are merely the summary of what we know by experience to have happened, and according to which we resolve upon our action. We know what has happened. We do not know, nor do we need to know, what will happen. Were any one truly to wish to know it, he would no longer be able to move and would be seized with such perplexity before life, that he would kill himself in desperation or die of fear. The egg, which usually takes five minutes to cook in the way that suits my taste, sometimes surprises me by presenting itself to my palate after those five minutes, either as too much or too little cooked; the step taken out of doors is sometimes a fall on the threshold. Nevertheless, the knowledge of this does not prevent me from leaving the house and cooking the egg, for I must walk and take nourishment. The laws of my individual being, of my temperament, of my aptitudes, of my forces, that is, the knowledge of my past, make me resolve to undertake a journey, as I did twenty years ago, to begin work upon a statue, as I did ten years ago. Alas! I had not considered that in the meantime my legs have lost their strength and my arm has begun to tremble. By all means call the previsions made use of in these cases true or false; but do not forget that they are nothing but empirical concepts, that is to say, mnemonic devices, founded upon historical judgments. There can be no doubt that they are useful; indeed, what we maintain is that just because they are useful, they are not true. If they possess any truth, it resides in the establishment of the fact. That is to say, it does not reside in the prevision and in the law, but in the historical judgment which forms its basis. [Sidenote: _Nature and its various meanings. Nature as passivity and negativity._]