And here a physical analogy may fitly be used to give the greatest definiteness to this cardinal truth. A mass of matter, of whatever kind, maintains its state of internal equilibrium, so long as its component particles severally stand toward their neighbors in equi-distant positions. Accepting the conclusions of modern physicists, which imply that each molecule moves rhythmically, then a balanced state implies that each performs its movements within a space bounded by the like spaces required for the movements of those around. If the molecules have been so aggregated that the oscillations of some are more restrained than the oscillations of others, there is a proportionate instability. If the number of them thus unduly restrained is considerable, the instability is such that the cohesion in some part is liable to fail, and a crack results. If the excesses of restraint are great and multitudinous, a trifling disturbance causes the mass to break up into small fragments. To which add that the recognized remedy for this unstable state is an exposure to such physical condition (ordinarily high temperature) as enables the molecules so to change their relative positions that their mutual restraints become equal on all sides. And now observe that this holds whatever be the natures of the molecules. They may be simple; they may be compound; they may be composed of this or that matter in this or that way. In other words, the special activities of each molecule, constituted by the relative movements of its units, may be various in their kinds and degrees; and yet, be they what they may, it remains true that to preserve internal equilibrium throughout the mass of molecules, the mutual limitations of their activities must be everywhere alike. And this is the above-described prerequisite to social equilibrium, whatever the special natures of the associated persons. Assuming that within each society such persons are of the same type, needing for the fulfillment of their several lives kindred activities, and though these activities may be of one kind in one society and of another kind in another, so admitting of indefinite variation, this condition to social equilibrium does not admit of variation. It must be fulfilled before complete life, that is greatest happiness, can be attained in any society; be the particular quality of that life, or that happiness, what it may.[G] § 62. After thus observing how means and ends in conduct stand to one another, and how there emerge certain conclusions respecting their relative claims, we may see a way to reconcile sundry conflicting ethical theories. These severally embody portions of the truth; and simply require combining in proper order to embody the whole truth.