I see many inputs to the discussion. I will try to get to the very essence of Buddha Dhamma to analyze this issue. Anicca is much deeper to comprehended by monitoring “body sensations”. It is all about changing one’s perceptions about how this world works (based on how the mind works), and how future suffering arises due to one’s own wrong perceptions.
The Buddha said that all living beings are trapped in a rebirth process, and most of these births are in realms that are filled with suffering. By cultivating panna (wisdom) about the real nature of this world, one can stop this rebirth process, and that he called attaining Nibbana. This was the key message of the Buddha. But most people today believe that Buddha taught about stopping the dukha vedana that one feels due to body aches, deceases, injuries etc.
This is why techniques like breath meditation and Goenka’s technique appeal to many people. They can see that some physical and mental relief can be achieved by using such techniques. In fact, some even can get to jhana, and then it becomes impossible for them to even seriously consider the true message of the Buddha. They get trapped in a “temporary oasis”.
Ultimately, Nibbana is realized ONLY when one sees the unfruitfulness and danger in the rebirth process. There is no refuge anywhere in the 31 realms, where it is a human, deva, or a brahma realm. One version of anicca is to see that anything that we do seek happiness in this world will not yield a permanent happiness. Rather, those actions can lead to future suffering that a normal human cannot even comprehend.
The first priority is to make sure one would not be born in the apayas (the four lowest realms), which includes the animal realm. That is where the suffering is worst. So, one first needs to understand how one COULD BE born in the apayas. What kind of deeds, actions, and thoughts will setup causes and conditions for one to be born in the apayas?
Therefore, one important aspect of realizing the anicca nature is to understand Paticca Samuppada (pati icca leading to sama uppada); see, “Paticca Samuppāda – “Pati+ichcha”+”Sama+uppāda” and other posts in that section.
When people seek temporary sense pleasures, they may do immoral deeds (papa kamma or apunnabhisankhara) to get them. For example, one may commit rape to get sexual satisfaction which lasts only a short time, but the consequences are unimaginably harsh. Such IMMORAL actions are done by animals and thus are associated with “animal gati”. Since one is attached to such “animal gati” and has a liking for them (pati icca), that can lead to births of similar nature (sama uppada). That is the basic idea, and you can read the section on Paticca Samuppada for details. (posts on “gati” can be found by using the Search box; I sometimes spell it as “gathi“).
The key point here is that the craving for such an extreme sense pleasure WILL lead to a future rebirth with very harsh suffering. The consequences are not determined by one’s desire, but by the root causes underlying one’s ACTIONS (KAMMA). There are ten such “bad actions” that will lead to suffering, and they are called dasa akusala; see, “Dasa Akusala/Dasa Kusala – Basis of Buddha Dhamma“.
In order to make this point clear, let us take one more example. One may kill another man in order to get his possessions (money, property, spouse, etc). So, the intent of that act is to make one’s life better, that is the “icca” or “desire”. One gets “bound” (“pati”) to this craving (“icca”) of hoping to make one’s life better by this killing and may even plan for many months to achieve that goal. However, the long-term consequences will be a birth in the niraya (lowest realm), where the suffering can last millions of years (“sama uppada” is due to the fact that killing a human is one of the worst dasa akusala and that is a future birth in a niraya or hell). This is a hard point to understand for many (how the consequences can be that harsh), but it will become clear as cleanses one’s mind by learning the true and pure Dhamma that the Buddha taught.
The key point is that any actions that involve dasa akusala, will have unimaginably harsh consequences. In other words, “one cannot maintain things to one’s expectations”. The above two are extreme examples of anicca nature, and that is where one should start. It is easy to see the main idea. Then one will start realizing the bad consequences of lesser actions like stealing,gossiping, etc.
When one comprehends this basic anicca nature of attaching to such “lowly cravings”, one’s mind will AUTOMATICALLY reject such thoughts. That is when one attains the Sotapanna stage and will be free from births in the apayas forever. That is when one starts on the Noble Path with a basic idea of anicca nature.
The next stage is to realize the anicca nature of ANY sense pleasure, and that leads to the Sakadagami and Anagami stages. But that is unimaginable for a normal human, and one should not contemplate on that far at the beginning.
The deepest level of anicca nature is realized only at the Arahant stage, where one sees the unfruitfulness and danger even in the higher brahma realms.
There are many posts at the site in various sections, providing different types of analyses on anicca. The main section is: “Anicca, Dukkha, Anatta“.
Those who are interested can scan through the site map and go through sections of interest, like “Sotapanna Stage“.
So, I hope I have clarified the key point that one must first understand the key message of the Buddha in order to make a true assessment of meditation techniques that do provide temporary relief. The key question to ask is how those techniques can lead to a true understanding of the anicca nature, which in turn will lead to “cessation of suffering” and attaining Nibbana.
If you think Goenka’s techniques do that, that is fine. Each person needs to make his/her decisions on such critical issues.