Source: http://www.bu.edu/wcp/Papers/Valu/ValuRiuk.htm

The summum bonum, the highest good, of human life is, according to both teleological and deontological theories, happiness, which is invariably regarded as the result or effect of moral or virtuous actions and thus as absolutely or essentially inseparable from them as its causes. This is but another way of saying that happiness is an inherent value, in fact the quintessence of all inherent values, while the moral or virtuous actions, thoughts etc. are the instrumental ones.

Since Aristotle defines happiness or eudaimonia as “the activity of reason in accordance with virtue in a complete life,”  we are tempted to conclude that happiness is not only distinct but also separate from virtues through which, as through its means, it is attained or produced. This, however, would be an erroneous conclusion since it would degrade happiness to the level of a mere artifact, which remains in existence even when the action producing it has been completed. For Aristotle – and for other eudaimonists such as hedonists and utiltarians – happiness is not a product but a process, a mental process, “activity of reason,” which lasts only as long as this process or activity lasts. Aristotle cannot mean by happiness, a purely concentrated intellectual effort in working, for instance, on a difficult mathematical, scientific, or philosophic problem, an intellectual effort shorn of emotional undertones. For in that case, he would make happiness, in spite of himself, unavailable to the bulk of humanity since only a minority are ever engaged in intellectual activity, and without the condition of universal availability, happiness, would cease to be the highest good. We will return to this later in this chapter. In the meantime, we must conclude that by happiness Aristotle can mean only a higher or lesser degree of conscious, and perhaps even unconscious, satisfaction or contentment with a particular kind of intellectual activity, and its result.

Since we called happiness an inherent value and the activity resulting in happiness, an instrumental value, we can see why they are inseparable. Returning to the requirement that happiness be available to all humans, it is plausible to conclude that Aristotle distinguishes three major forms of happiness – one for each part making up the human nature: rational, sensitive, and vegetative. In this way, happiness would indeed be accessible to all humans, though its forms or levels would be different. Even at the lowest, biological level, any one engaged in the activities of eating, drinking, etc. with moderation could be correctly said to be enjoying happiness in so far as they are deriving the sense of satisfaction, fulfillment, and enhancement of their health. By the same token, the next level of life, the social and emotional, would add another, a higher, dimension to happiness in most individuals, to be capped by the intellectual level but only in a few fortunate people. All these considerations show that, as noted before, happiness is not a product but a process, or more exactly, a chain of complex processes as well as memories or echoes of them, and that the inherent values are inseparable from instrumental ones.