Pursuant to this theory, Demokritus proclaimed that all the properties of objects, except weight, hardness, and softness, were not inherent in the objects themselves, but simply phenomenal and relative to the observer--"modifications of our sensibility". Colour, taste, smell, sweet and bitter, hot and cold, &c., were of this description. In respect to all of them, man differed from other animals, one man from another, and even the same man from himself at different times and ages. There was no sameness of impression, no unanimity or constancy of judgment, because there was no real or objective "nature" corresponding to the impression. From none of these senses could we at all learn what the external thing was in itself. "Sweet and bitter, hot and cold (he said) are by law or convention (_i.e._ these names designate the impressions of most men on most occasions, taking no account of dissentients): what really exists is, atoms and vacuum. The sensible objects which we suppose and believe to exist do not exist in truth; there exist only atoms and vacuum. We know nothing really and truly about an object, either what it is or what it is not: our opinions depend upon influences from without, upon the position of our body, upon the contact and resistances of external objects. There are two phases of knowledge, the obscure and the genuine. To the obscure belong all our senses--sight, hearing, smell, taste, touch. The genuine is distinct from these. When the obscure phase fails, when we can no longer see, nor hear, nor smell, nor taste, nor touch--from minuteness and subtlety of particles--then the genuine phase, or reason and intelligence, comes into operation."[210] [Footnote 210: Demokritus, Fr. p. 205, Mullach; Sextus Empiric. adv. Mathemat. vii. p. 135; Diogen. Laert. ix. 72.] [Side-note: Reason alone gave true and real knowledge, but very little of it was attainable.] True knowledge (in the opinion of Demokritus) was hardly at all attainable; but in so far as it could be attained, we must seek it, not merely through the obscure and insufficient avenues of sense, but by reason or intelligence penetrating to the ultimatum of corpuscular structure, farther than sense could go. His atoms were not pure Abstracta (like Plato's Ideas and geometrical plane figures, and Aristotle's materia prima), but concrete bodies, each with its own[211] magnitude, figure, and movement; too small to be seen or felt by us, yet not too small to be seen or felt by beings endowed with finer sensitive power. They were abstractions mainly in so far as all other qualities were supposed absent. Demokritus professed to show how the movements, approximations, and collisions of these atoms, brought them into such combinations as to form the existing Kosmos; and not that system alone, but also many other cosmical systems, independent of and different from each other, which he supposed to exist.