I see new comments by Chigstarr, Embodied, and Johnny at various places above. I think it is essential to understand what is meant by samadhi, jhana, and “peace of mind”.
Johnny asked: “If someone who is doing sitting meditation could contemplate on deep dhamma concepts like Tilakkhana and Paticca Samuppada for an hour or more, with little to no other stray thoughts, is he considered to be in Samadhi?”
Short answer is, YES.
But it needs to be understood what is meant by samadhi:
“What is samādhi? – Three Kinds of Mindfulness“.
Samadhi can be thousands of different types. There are micca samadhi too, which are opposite of samma samadhi. Samadhi means “the mind gets pulled into that direction”. Normally, one’s mind will become peaceful when one’s mind gets pulled in the “moral direction” since that makes the mind less cluttered with akusala or sensual thoughts.
Samadhi is not necessarily jhana. Jhana are really mental states of beings in rupa and arupa realms. So, when one is in a jhana, it feels much better overall since they are higher mental states mostly devoid of akusala and sensual thoughts:
“Samādhi, Jhāna, Magga Phala – Introduction“.
One can get to magga phala via Samma Samadhi and also via jhanas:
“Samādhi, Jhāna (Dhyāna), Magga Phala”
@Chigstarr: So, when one does any type of common meditations, one’s mind could become peaceful, and I said so in my previous comments. I never said otherwise. During the time of the Buddha, Devadatta attained even supernormal powers with such techniques, but he lost all that at the end. He never understood Tilakkhana.
The message of the Buddha is not just to go after a calmed mind (or even jhanas or supernormal powers), but to attain magga phala and get out of the suffering-filled rebirth process. But that idea may not be even palatable to many people. That is because they don’t have an understanding of Tilakkhana (anicca, dukkha, anatta). So, there is no point in discussing this issue if one has already decided that all one needs is a “peace of mind”. What this website is focusing on is magga phala, and specifically the Sotapanna stage, which will stop future rebirths in lower realms. Therefore, the bottom line is that: if one can show that Goenka’s techniques can lead to magga phala, we can have a discussion on that.
Also, “A Buddhist or a Bhauddhaya?” and “Buddha Dhamma: Non-Perceivability and Self-Consistency“.