The doctrine of karma is not as easy as ‘do good and you will receive good’. But it also doesn’t mean ‘think good thoughts and your will get a good life’. The truth is – it means both and neither. I’ll illustrate with the help of some quotes from the Buddha:
349. For a person tormented by evil thoughts, who is passion-dominated and given to the pursuit of pleasure, his craving steadily grows. He makes the fetter strong, indeed.
[The Dhammapada: The Buddha’s Path of Wisdom, translated from the Pali by Acharya Buddharakkhita]
Which really just means: evil thoughts strengthen the delusions that keep us from Nirvana. Evil thoughts bring on more evil thoughts.
Which might make one think that it is only the mind which matters. But consider the following quote, also from the Dhammapada:
Don’t underestimate evil
(‘It won’t amount to much’).
A water jar fills,
even with water
falling in drops.
With evil — even if
the fool fills himself full.
Obviously most of our actions are not so clearly either good or evil. Nor are our thoughts and words so clearly set. Wouldn’t that be nice? To have a nice clearcut label ‘this is a good thought’ attached to every one of our pure thoughts? And labels of a similar kind ‘this thought is only based in fear, it’s neither true nor helpful’ and ‘this thought will do you harm, discard it immediately’ and ‘this thought will harm the people you love’ or ‘this thought is part of your culture, but very dangerous to mankind as a whole’…
It comes down to self knowledge, and that is, unfortunately very hard.
Which brings me back to the Dhammapada:
Life’s easy to live
for someone unscrupulous,
cunning as a crow,
forward, & brash;
but for someone who’s constantly
pure in his livelihood,
clean in his pursuits,
This seems to suggest that the better a person one is, the harder life will be… Not quite the usual interpretation of karma, is it?