J. S. Mill, going further, says: "Our knowledge of objects, and even our fancies about objects, consist in nothing but the sensations they excite, or which we imagine them exciting in ourselves.... This knowledge is merely phenomenal.... The object is known to us only in one special relation, namely, as that which produces, or is capable of producing certain impressions on our senses; and all that we really know is these impressions."[34] Herbert Spencer asserts the relativity of all knowledge, and says: "Clearly as we seem to know it, our apparent knowledge proves on examination to be utterly irreconcilable with itself. Ultimate religious ideas and ultimate scientific ideas, alike turn out to be merely symbols of the actual, not cognitions of it."[35] Plainly these theories do not make our knowledge a genuine apprehension of reality, but merely internal and unreliable mental states. It is only a subjective phenomenon. We cannot know that it stands for the real truth of things. Rather, we are told, it does not. It is but an effect within the mind, determined, it may be, by things without, but modified, if not created, by the constitution and action of the mind itself. The receiving mind, like the receiving lens, determines the shape and color of the apprehended phenomenon. If there be any reality behind it and correspondent to it, we can never assure ourselves of it. The theory thoroughly discredits the trustworthiness of our faculties, both of sense-perception and of reason. They do not report the things of the world as they really are, but merely as they affect us. Our necessary conceptions, such as time, space, beauty, cause, moral law, cannot be proved to be anything else than phenomena within us. The conclusion is well stated in the language of Mr. Grote in his explanation of the views of the Greek sophists: "As things appear to me, so they are to me; as they appear to you, so they are to you."[36] It is altogether a subjective matter. We can have only a relative morality--not conformed to an objective and universal standard, but to the particular impressions we find within us.