A physicist said that the reason why the chair is able to hold my weight is because of Heisenberg's Uncertainty principle. His reasoning was that when the atoms of my body are in contact with that of the chair, the electrons in the my body push against the electrons in the chair. Thereby forcing the electrons to a smaller region of space. Due to HU princple the more accurately we can determine the position of particles, the more wide ranging their momentum. Therefore when I sit on a chair, the electrons in the chair due to their high momentum push against my electrons hence providing pressure to hold me up. That is the reason why the chair is able to support me. I am not fully comfortable with this explanation but that is due only to my basic understanding of QM My inital reaction would be simply that when I sit on a chair, the electrons in my body will repel that in the chair due to the electromagnetic force. It is this repelsion that provides the reason why the chair is able to support me. The protons in my body and that of the chair are on average too far away to exert any attractive force. It seems that my idea and that of the physicist is completely different. Can someone offer some insight here?