Is Solo Travel Ever Truly Solo?

I love solo travel. Any regular readers of this site can attest to that fact. I honestly think it is the best way to travel and the majority of my backpacking trips over the last decade have been on my own. But looking back I have to ask, has it ever been truly solo travel? Sure I have had times where I have been trekking in the jungle or camping out in the desert where yes, I have been alone.