From this point of view there is no higher and no lower sense.

The sensations of sight, apparently so objective and so searching, no more take us out of ourselves than do the sensations of taste which are localised in the tongue.
In short, our nervous system, which enables us to communicate with objects, prevents us, on the other hand, from knowing their nature.

It is an organ of relation with the outer world; it is also, for us, a cause of isolation.

We never go outside ourselves.

We are walled in.
And all we can say of matter and of the outer world is, that it is revealed to us solely by the sensations it affords us, that it is the unknown cause of our sensations, the inaccessible excitant of our organs of the senses, and that the ideas we are able to form as to the nature and the properties of that excitant, are necessarily derived from our sensations, and are subjective to the same degree as those sensations themselves.
But we must make haste to add that this point of view is the one which is reached when we regard the relations of sensation with its unknown cause the great _X_ of matter.[7] Positive science and practical life do not take for an objective this relation of sensation with the Unknowable; they leave this to metaphysics.