Can I put into Acknowledgments someone who is no longer living?
I would reserve the acknowledgments section for people or organizations that directly contributed to the paper.  For example, if you talked with Erikson while he was still alive and he offered advice or suggestions, then it would be appropriate to thank him in the acknowledgments.  If you were just inspired by his papers, then it is better to discuss that elsewhere in the paper.  For example, you could note in the introduction that your approach is inspired by Erikson's work on psychological development, or you could mention this background when you define the terms based on his theory.  But if you thank him in the acknowledgments section, then people will assume there was a more personal connection unless you clearly specify otherwise ("Although I was never lucky enough to discuss this work with him in person, I owe Erik Erikson a great debt for...").

The main thing you should not do when thanking a deceased person is to attribute opinions to them, because they are not around to contradict you.  For example, you should not thank them in a way that suggests they supported your work, even if it's true, unless you have some documented proof.  For example, it's awkward to write "I am deeply grateful to Erik Erikson for his steadfast belief in my theory."