What's the difference between 心, 念, and 意?

Question

I can say that after much research on this, I'm more thoroughly confused than before I started. I'm talking mostly about when they are used as suffixes, but the concept applies when they stand alone, or even start some words.

At first it seemed like 心 is used more to describe the core/root nature of something, and the other two are more for momentary/temporary states of mind. But I've found so many examples where the definitions appear to overlap that I'm just not sure any more. One dictionary definition I found comparing 意 and 念 indicates that 意 is a more temporary, outward appearance, while 念 is something deeper.

「意」が表面的、一時的な心の動きも含むのに対して、「念」はもっと深く心に思う気持ち。

But again, there are many examples that I can find where I'm not sure of the nuances between them.

• 疑心・疑念・But no 疑意
• 信心・信念・But no 信意
• 念願・心願・But no 意願　→　念願 is like a "neutral" desire/wish, whereas 心願 conveys a religious desire/wish/prayer
• 感謝の念・感謝の心・謝意
• 専心・専念・専意　→　All seem to mean the same
• [悪心]{あく・しん}・悪念・悪意　→　First two similar (intent to do something bad), last is different (malice, ill will (toward someone))
• 心のまま・意のまま・念のまま？

Questions

1. What are the nuances between these three?
2. Are there any hard rules on when you can use them or not use them? (Like examples above - why isn't 疑意 acceptable?)

Answer 1

I'm not sure about hard and fast rules, but here's what I think:

I think 心 is used when it is a natural flow, and does not involve too much deliberation and exertion of strong will. 意 involves intention and volition. 念 gives me the impression that an idea has been persisting in the person's mind and he is considering it.

The short version:
心 - The inherent nature
意 - The intention
念 - The (persisting) thought

(To me they are three rather different words, so I did not think of comparing them)

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For 疑心, your doubt is a product of your 心; it is not directly your intention to doubt, that is why 疑意 is a little strange. It is difficult to intend to doubt something, you simply just doubt it because of a gut feeling.

But 疑念 is possible because if there are some reasons to doubt, the idea persists in the mind and is under consideration whether it can be trusted or not.

Compare this with 善心 and 善意, it is both possible that goodness is a product of your 心, and it is also possible to intend to do good.

For 悪心, 悪念 and 悪意:

悪心 is when badness flows naturally out of the 心, it suggests that the person is inherently bad because his 心 is bad.

悪念 is the thought of doing bad things.

悪意 is when there is intention to do bad.

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