This is a completely false statement. We understand all the motivations that bring meaning to this existance. It is the meaning that shapes us yet, the source for all that is meaningful, that which gives us reason to act and exist, that remains scientifically undefinable and unmeasurable. A scientific measurement of love or any other emotion is meaningless and unatainable under the scope of current scientific knowledge.
We do?? What are the motivations that bring meaning to this existance?
Do you understand it? What is the source?
You can make claims about the 'motivations', you can make claims about the 'source'. That might be what you believe. That is just your interpretation and your belief. It has no 'Meaning' outside of you.