Aristotle makes it clear that the first lesson should not be a cause for despair or a justification for reducing one’s efforts with respect to accomplishing a goal or task. On the contrary, this insight, as painful as it may be, will be liberating for the individual who can accept the lesson and integrate into his or her life because he or she will recognize just how many different variables need to be considered in order to take a single action. It is this recognition that leads to Aristotle’s second lesson for human beings that is delivered in Book Two of On the Heavens. Because human beings are singular among all sentient creatures for their highly developed cognitive capacity, they have more options available to them than other species. “[O]n our earth,” he writes, “it is man that has the greatest variety of actions-for there are many goods that man can secure.”[8] By goods, Aristotle is not referring to material items, but to the results of his actions. He goes a step further, though, and offers a cautionary caveat. For humans, the power that is endowed with the freedom of action also comes with serious responsibilities: “[A]ction always requires two terms[:] end and means.”[9] Thus, while Aristotle’s first lesson suggests that there are some aspects of the outcomes of our action that are often beyond our own sphere of influence or control, his second lesson affirms that we must always be cognizant of the ways in which that over which we do have control will affect others, both our fellow human beings and other creatures, as well as the planet itself.
The third lesson which Aristotle offers and upon which he expounds is one that considers the compulsion to question, to try to understand, to discover, and to make theories and pronouncements about the ways the world works. Clearly, this is a subject that is near and dear to Aristotle’s own heart; indeed, it is the preoccupation of his entire existence. Throughout Book Two of On the Heavens, Aristotle returns time and again to a consideration of what it means to try to understand those processes that are mysterious and not wholly visible, even to the most careful and devoted of observers. He moves fluidly back and forth between worrying whether he is indulging in “excessive folly or excessive zeal” in trying “to provide an explanation of some things”[10] and asserting firmly and declaratively that he has every right to do so. Over the course of this book, Aristotle seems to resolve his ambivalence, making frequent proclamations that that idea or theory which he has dismissed is clearly “a mere fiction and quite inconceivable,”[11] and attempting to persuade the reader that he has made his point convincingly, that it is beyond reproach or question, and that the matter “has now been sufficiently explained”[12] and is, therefore, resolved.
What is the lesson, then, that is to be wrung from Aristotle’s own reflective process, from his own effort to integrate and apply the preceding two lessons which he has shared with the reader? The philosopher himself delivers the lesson clearly and neatly, if only the reader can extract it from the more difficult content within which it is embedded. “[O]ne should first consider what reason there is for speaking,” he writes, “and also what kind of certainty is looked for.”[13] The lesson is not just applicable to the pensive work of the philosopher or sages, but to any human endeavor. What Aristotle teaches the reader is that each human action is put into motion by a motivating force, and is done so with intention. The attention with which intention is applied, however, is not always conscious; it is, in fact, frequently careless. While the heavenly, or “spherical,”[14] forces of the universe can operate unconsciously because they are operating according to the conscious design of an unseen force that is, at once, “primary and simple and ungenerated and indestructible,”[15] human beings must act more consciously and, at the same time, more conscientiously.
“[E]verything that is moved is moved by something,”[16] Aristotle reminds the reader. He is speaking not just of physical movement, however. By referencing the idea of movement, Aristotle is referring to all action that humans put into motion as much—if not more so– about the movement of intention and of our psyches than of the physical actions that we take. He is also referring though, to the actions of which we are recipients. Whenever our movements, psychological and physical, are not considered carefully, what Aristotle refers to as an “irregularity of movement” will result.[17] Such “irregularity of movement,” he contends, “must lie either in the mover or in the moved or both.”[18] He goes on to explain: “For if the mover moved not always with the same force, or if the moved… did not remain the same, or if both were to change, the result might well be an irregular movement in the moved.”[19] The mover and the moved exert a force upon one another; they are in dynamic relationship and, at times, in dynamic tension. To prevent an imbalance—an occurrence which can never “be conceived of as actual in the case of the heavens” but which is far more common among human beings—one must always be conscious of his or her actions and reactions.[20]
The reader begins to see, then, how this final lesson from Book Two of On the Heavens relates to the ones that precede it. Couched within the dense and pensive musings of the mechanics of the planets and the heavens, Aristotle has hidden three valuable lessons that actually help the reader understand more about himself or herself and his or her place within the universe. Far from being esoteric, the three lessons are perhaps surprisingly pragmatic and just as unexpectedly spiritual. The lessons that Aristotle conveys in On the Heavens are both timeless and universal, and they have been incorporated and conveyed in many other philosophical, religious, and literary texts that have been produced since Aristotle’s epoch. First, as humans we must understand our limitations. In spite of the best preparation and our best efforts, we will not always succeed in reaching our goals; at times, our plans will go awry. Second, this is especially the case when we fail to consider the means and the ends of our actions and, most importantly, how these will affect other people and the overall order of things. Third, we must be thoughtful and decisive about our actions, able to defend them by explaining why we do what we do. Throughout this book, Aristotle models all three behaviors, and though the text can be challenging to read, a close analysis shows how Aristotle activates all three lessons and puts them into effect. While the reader who can comprehend some of the more mechanical and technical aspects of On the Heavens will be more likely to derive more meaning from the complex theoretical constructs that Aristotle develops, it is not entirely necessary to comprehend these or even to agree with them in order to derive some profound, timeless, and universal lessons about the role of humankind in the affairs of the universe. As much as he devises a convincing cosmology, perhaps the more meaningful part of On the Heavens is contained in three simple lessons about how to live more thoughtfully in day-to-day life.

Work Cited
Aristotle. On the Heavens. [Electronic Version]. Retrieved on November 18, 2007 from http://classics.mit.edu/Aristotle/heavens.2.ii.html

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[1] Aristotle. On the Heavens. Book 2, Chapter 12, para. 3.
[2] Aristotle. On the Heavens. Book 2, Chapter 12, para. 3.
[3] Aristotle. On the Heavens. Book 2, Chapter 12, para. 5.
[4] Aristotle. On the Heavens. Book 2, Chapter 4, para. 4.
[5] Aristotle. On the Heavens. Book 2, Chapter 12, para. 3.
[6] Aristotle. On the Heavens. Book 2, Chapter 12, para. 3.
[7] Aristotle. On the Heavens. Book 2, Chapter 12, para. 3.
[8] Aristotle. On the Heavens. Book 2, Chapter 12, para. 3.
[9] Aristotle. On the Heavens. Book 2, Chapter 12, para. 3.
[10] Aristotle. On the Heavens. Book 2, Chapter 5, para. 1.
[11] Aristotle. On the Heavens. Book 2, Chapter 6, para. 2.
[12] Aristotle. On the Heavens. Book 2, Chapter 6, para. 3.
[13] Aristotle. On the Heavens. Book 2, Chapter 5, para. 1.
[14] Aristotle. On the Heavens. Book 2, Chapter 4, para. 1.
[15] Aristotle. On the Heavens. Book 2, Chapter 6, para. 2.
[16] Aristotle. On the Heavens. Book 2, Chapter 6, para. 2.
[17] Aristotle. On the Heavens. Book 2, Chapter 6, para. 2.
[18] Aristotle. On the Heavens. Book 2, Chapter 6, para. 2.
[19] Aristotle. On the Heavens. Book 2, Chapter 6, para. 2.
[20] Aristotle. On the Heavens. Book 2, Chapter 6, para. 2.