user157: Considering the 12 nidanas as represented on the Tibetan wheel of life.
I can understand how the previous links cause (or condition) the subsequent ones for instance sensation is a condition for craving. However as the wheel turns it does 
birth -> conditions -> death -> conditions -> ignorance

In what way is death a condition for ignorance? I can't see a casual link there.

user295: I am answering from the Theravada standpoint. (hoping this also will add some value)
Death is:

breaking of the aggregates due to decay or some accident, end of sustainable life span

Rebirth:

reformation of the aggregates

As long as the wheel of dhamma is turning, each time the aggregates breakup in one body it forms in another and rebirth. Even in this life the argeragers are arising and passing away. At death the aggregates pass away in this body but arises again in another body.
Eliminating ignorance causes the links in this cycle to break.You are not adding fuel to the fabrication process. Once this life ends there is no power for the aggregates to form in another body. So there are no more rebirths. If there is no rebirth there is not death or any of the calamities that follow birth.

user900: It is taught by some teachers (if not many) the chain of dependent origination is divided into 3 lifetimes: past, present, and future. However, because each part describes a single lifetime, I think each part is simply one of 3 ways we can look at our present experience.
We can see our present experience in the sense that our ignorance gives rise to karmically potent volitional formations. Or, we can go deeper and see the conditioned nature of our experience in terms of the aggregates and how ignorance leads to craving (and eventually becoming) after feeling. Or, we can look at our present experience in terms of birth, aging, sickness, and death (as suffering). I think the Buddha wanted us to use all 3 ways as different tools for investigation of ignorance.
This would mean that the dependent chain of origination taught by the Buddha refers to the conditioning process of a being fettered by ignorance. In that case, it would also be justified to say that the chain refers to 3 different life times because the "present" life time contains the teaching of the aggregates, which are present (to my understanding) for all beings, enlightened and unenlightened, whereas the "past" and "future" lifetimes concern the unenlightened being (since enlightened beings aren't ignorant, they don't create karma; birth, aging, sickness, and death refer to dukkha and future rebirth which is not applicable present for the enlightened being).

user43: Bhava-chakra, the wheel of life, or, as I would translate it, "the wheel of individuation" is a relatively late depiction of the 12 Nidanas. In the suttas of Pali Canon, the nidanas are usually presented as a list, that is reviewed both in forward as well as in reverse direction -- but never (to my knowledge!) as an infinite loop.
If you read the wheel clock-wise, the 12 nidanas are:
avidya -> samskara -> vijnana -> nama-rupa -> six ayatana -> phassa -> vedana -> tanha -> upadana -> bhava -> jati -> jaramarana & dukkha
Although the interpretation of the wheel as depicting the cycle of death-and-rebirth is accepted by most schools, according to Triyana framework it represents the basic/literal ("hinayana") level of understanding.
Instead, some instructors, including Chogyam Trungpa Rinpoche, taught twelve nidanas as a process of gradual individuation, or emerging and hardening of the illusory ego.
In this line of thinking, avidya is the innate ignorance, samskaras are the arbitrary imprints of sensory stimulation, vijnana is inductive intelligence born from the imprints, nama-rupa are inductively postulated external objects, six ayatanas are the implied "windows" onto the world, phassa is a subjective experience of contact with the postulated objects, vedana is a sensation attributed to the contact, tanha is an obsessive replay of the contact and sensation, upadana is feeding the obsession by making its object one's goal, bhava is becoming the "this" of here-and-now, dependently-co-arisen with the twofold "that" of space-and-time, jati is identifying with a living organism, and jaramarana is experiencing the organism's perspective culminating in death.
(Because the list shows subjective experience, not an objective physical process, the physical birth is not shown, but if it were, it would fit right before Ignorance. The Birth that is shown, is not a physical birth, but conceptual (subjective) assumption that one is an individual living organism.)
Although 12 nidanas explained this way describe subjective experience of one sentient being, which begins with physical birth and ends with death, we could say that after death the cycle logically "restarts" from scratch, again starting from ignorance, progressing through individuation, and culminating in death of another "being" and so forth indefinitely.
To be sure, objectively there is no cycle, beings arise and cease asynchronously, but in some sense we could say that death of a (unenlightened) being is a return to innate ignorance.
@ChrisW found a tremendously elegant quote in Wikipedia:

When the cessation of the continuity of experience occurs, we speak of death. It is the total breakdown and dissolution of experience and experiencer. The process of disintegration, destructuring, and entropic scattering yields a nexus of vibratory murkiness which is the condition of avidyā, the first motif. Thus the entire structure of patterning feeds back on itself.


157: <p>Considering the 12 nidanas as represented on the Tibetan wheel of life.</p>

<p>I can understand how the previous links cause (or condition) the subsequent ones for instance sensation is a condition for craving. However as the wheel turns it does </p>

<pre><code>birth -&gt; conditions -&gt; death -&gt; conditions -&gt; ignorance
</code></pre>

<p>In what way is death a condition for ignorance? I can't see a casual link there.</p>
 295: <p>I am answering from the Theravada standpoint. <em>(hoping this also will add some value)</em></p>

<p>Death is:</p>

<ul>
<li>breaking of the aggregates due to decay or some accident, end of sustainable life span</li>
</ul>

<p>Rebirth:</p>

<ul>
<li>reformation of the aggregates</li>
</ul>

<p>As long as the wheel of dhamma is turning, each time the aggregates breakup in one body it forms in another and rebirth. Even in this life the argeragers are arising and passing away. At death the aggregates pass away in this body but arises again in another body.</p>

<p>Eliminating ignorance causes the links in this cycle to break.You are not adding fuel to the fabrication process. Once this life ends there is no power for the aggregates to form in another body. So there are no more rebirths. If there is no rebirth there is not death or any of the calamities that follow birth.</p>
 900: <p>It is taught by some teachers (if not many) the chain of dependent origination is divided into 3 lifetimes: past, present, and future. However, because each part describes a single lifetime, I think each part is simply one of 3 ways we can look at our present experience.</p>

<p>We can see our present experience in the sense that our ignorance gives rise to karmically potent volitional formations. Or, we can go deeper and see the conditioned nature of our experience in terms of the aggregates and how ignorance leads to craving (and eventually becoming) after feeling. Or, we can look at our present experience in terms of birth, aging, sickness, and death (as suffering). I think the Buddha wanted us to use all 3 ways as different tools for investigation of ignorance.</p>

<p>This would mean that the dependent chain of origination taught by the Buddha refers to the conditioning process of a being fettered by ignorance. In that case, it would also be justified to say that the chain refers to 3 different life times because the "present" life time contains the teaching of the aggregates, which are present (to my understanding) for all beings, enlightened and unenlightened, whereas the "past" and "future" lifetimes concern the unenlightened being (since enlightened beings aren't ignorant, they don't create karma; birth, aging, sickness, and death refer to dukkha and future rebirth which is not applicable present for the enlightened being).</p>
 43: <p><code>Bhava-chakra</code>, the wheel of life, or, as I would translate it, "the wheel of individuation" is a relatively late depiction of the 12 Nidanas. In the suttas of Pali Canon, the nidanas are usually presented as a list, that is reviewed both in forward as well as in reverse direction -- but never (to my knowledge!) as an infinite loop.</p>

<p>If you read the wheel clock-wise, the 12 nidanas are:</p>

<p><code>avidya -&gt; samskara -&gt; vijnana -&gt; nama-rupa -&gt; six ayatana -&gt; phassa -&gt; vedana -&gt; tanha -&gt; upadana -&gt; bhava -&gt; jati -&gt; jaramarana &amp; dukkha</code></p>

<p>Although the interpretation of the wheel as depicting the cycle of death-and-rebirth is accepted by most schools, according to Triyana framework it represents the basic/literal ("hinayana") level of understanding.</p>

<p>Instead, some instructors, including Chogyam Trungpa Rinpoche, taught twelve nidanas as a process of gradual individuation, or emerging and hardening of the illusory ego.</p>

<p>In this line of thinking, <code>avidya</code> is the innate ignorance, <code>samskara</code>s are the arbitrary imprints of sensory stimulation, <code>vijnana</code> is inductive intelligence born from the imprints, <code>nama-rupa</code> are inductively postulated external objects, six <code>ayatana</code>s are the implied "windows" onto the world, <code>phassa</code> is a subjective experience of contact with the postulated objects, <code>vedana</code> is a sensation attributed to the contact, <code>tanha</code> is an obsessive replay of the contact and sensation, <code>upadana</code> is feeding the obsession by making its object one's goal, <code>bhava</code> is becoming the "this" of here-and-now, dependently-co-arisen with the twofold "that" of space-and-time, <code>jati</code> is identifying with a living organism, and <code>jaramarana</code> is experiencing the organism's perspective culminating in death.</p>

<p>(Because the list shows <em>subjective experience</em>, not an objective physical process, the physical birth is not shown, but if it were, it would fit right before Ignorance. The Birth that <em>is</em> shown, is not a physical birth, but conceptual (subjective) assumption that one is an individual living organism.)</p>

<p>Although 12 nidanas explained this way describe subjective experience of <em>one</em> sentient being, which begins with physical birth and ends with death, we <em>could</em> say that after death the cycle logically "restarts" from scratch, again starting from ignorance, progressing through individuation, and culminating in death of another "being" and so forth indefinitely.</p>

<p>To be sure, objectively there is no cycle, beings arise and cease asynchronously, but in some sense we could say that death of a (unenlightened) being is a return to innate ignorance.</p>

<p>@ChrisW found a tremendously elegant <a href="http://en.wikipedia.org/wiki/Twelve_Nid%C4%81nas#Aging.2C_decay_and_death" rel="nofollow">quote in Wikipedia</a>:</p>

<blockquote>
  <p>When the cessation of the continuity of experience occurs, we speak of death. It is the total breakdown and dissolution of experience and experiencer. The process of disintegration, destructuring, and entropic scattering yields a nexus of vibratory murkiness which is the condition of <em>avidyā</em>, the first motif. Thus the entire structure of patterning feeds back on itself.</p>
</blockquote>
