Looked at from this position, reality is not a fact but a problem and an ideal; it does not lie at the beginning but at the end of the course: it is different with different individuals, peoples, and times; each in its particular nature and work has its own reality. Thus we cannot comprehend the problem of reality from experience without conceiving reality as existing in flux: the assertion of an independent spiritual life, transcendent over all human undertaking, is a sufficient safeguard against a destructive relativism. It is one of the most troublesome appearances in the conflicts of minds that they fail to recognise the many-sidedness and fluidity of our conceptions of reality; that each takes his conception as the self-evident one and urges it upon the others. In this way originate the many unfruitful disputes concerning this world and the next, immanence and transcendence, in which the most external and superficial conception is usually presented as self-evident; while yet, according to the fundamental relation and the chief basis of life, very different conceptions arise, and as a fact, systems of thought nowhere come into more severe conflict than with regard to their conceptions of reality. Only to a mode of thought which, without further consideration, accepts the world of sense as the genuine and only reality, can philosophy and religion, for example, appear to be occupied with things implying an "other" world, and which, therefore, are incomprehensible. On the contrary, Augustine thought to attain to genuine reality and at the same time a true life only by elevation to a realm above sense, so that to him the world of sense was secondary and derivative.