space as actual? When such thinkers as Kant, or Lotze, have felt themselves forced to the view that space is ideal, we should hesitate to infer its actuality from the presence of the idea in our minds. If we say that mind is non-spatial, we have passed the primitive stage of thought which gives a spatial character to everything. It may be that the objectivity of space should be eliminated altogether. It may be, after all, that we should regard this idea as an effort to render intelligible to ourselves the universe; and it may be, we should regard it as a mistake.
In short, those who contend for intuitions should recognize, first, that they are constructing a theory of the mind which is itself problematical; and, further, that were their theory established, they would still have the task of showing that such intuitions have objective applications.
If, in such a case as we have considered, certainty has not been found, we need not look for it in the laws of the particular sciences. These, or some of them, are in current language spoken of as absolutely certain, but a little reflection shows that they are hypotheses, which further experience may show to be untenable. Yet this question is not to be confounded with the question as to the place of certainty within the domain of a particular observational science. Wundt, in his Logik, discusses the criteria of certainty, and shows that that is certain which in the course of advancing experience does not admit of correction. The proof of such certainties can be put in the form of a disjunctive syllogism. Thus, either the earth moves round the sun, or the sun moves round the earth. The latter supposition is impossible. Therefore the earth moves round the sun. The certainty in such a case seems to be absolute. Yet it is unnecessary to show that it depends on a number of assumptions as to space and motion. It is a hypothetical certainty.
We seem justified in concluding that our judgments, so far as they refer to reality, are not possessed of absolute certainty. We are trying to interpret the universe, but we often fail to catch its meaning; and a long experience of mistakes has
