Your wording is too complex. "To grasp" is the same as "to understand"; "The attitude" is the same as "their philosophy." So you do not need both. Perhaps I can rephrase it:
We grasp their attitude toward life by watching how they conduct themselves in life.
If this helps your understanding, fine. However it is not an easy approach or one that is always clear to state. I will make a couple of comments, but I will not try to untie the big knot of your idea.
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Could I say so and do with graphical way?
1. He is good. = He has / shows a quality of goodness. (the "is"
Hi Doctor D, More surprisingly, your suggestions exactly meet me. We know English is the style of theoretical thinking and your answer suggested that there are some of the features of your personality, those I think are giving cause for the surprisingly meeting. Thank you for your help so much. Some questions those I have long bided: