I act so I am

By far my most successful blog is “I act, therefore I am”, written about twelve years ago. It has been read already more than 16,000 times, while my second successful blog (“By accident” and “by mistake”) has been read “only” 5,000 times. In the blog “I act, therefore I am” I defend the view that, unlike what Descartes says, it is not our thinking that is fundamental for us but that our acting is. Or as Christine M. Korsgaard says in her book Self-Constitution: “[A]ction is self-constitution. … [W]e human beings constitute our own personal or practical identities … through action itself” (p. 45). However, when I reread this blog now after so many years, I find it quite cryptical, but that regards the way I worded my view, not the view itself.
Take for instance a brain in a vat. It’s an example used by several philosophers in order to substantiate their views. Sometimes it is also used by me, but then in order to refute such views. Some philosophers (to start with John Locke) think that actually my body is not important for my personality. My question is then: So why have one? It would be enough to be a brain in a vat in order to exist. However, if you would be not more than a thinking brain in a vat that couldn’t express itself in some way, what would you be then? A minimal way to express yourself, even if it is only with the help of others or via others, is required or otherwise you cannot exist. And even a minimal way of expressing yourself is a way of acting. For even a minimal expressing of yourself, anyway, has the characteristics of an action: It is guided by perception (the mental stuff put into your brain by the person responsible for keeping you there as a brain in a vat plus your memories from the time before you were in this deplorable situation); the expression is guided by an intention; and the expression is yours, it is “attributable to you”, as philosophers say. And the body? Haven’t I always stressed in my blogs that a person needs a body? With the exception of the stuff that makes up the brain, you as a brain in a vat doesn’t have a real body, indeed, but just as many people have artificial limbs, the person who notes your expressions and executes them functions as your (artificial) body. In this way, we can defend that even a minimal you as a brain in a vat is constituted by your actions, as long as you can express yourself. If not, there is no way to say that you exist. Since already a self-expressing brain in a vat is constituted by his or her expressions, this is even more so for a more or less “normal” person.
I could give more philosophical reasons for my thesis, but as important is that there are also psychological reasons that man is constituted by his or her actions. I’ll give an example. You want to make a tour in the countryside and so you buy a day-ticket for a bus and let yourself drive around. Or, alternatively, you make a tour by bike or walking. Psychological investigations say that in such situations you see more and remember by far better what you have seen when you go by bike or walk than when you do a bus tour, for when you cycle or walk you are active, while in the bus you just sit down and are mainly passive.
Only by acting you exist. However, it is not only so that you have become what you are by acting, in fact your acting is what constitutes you and not your thinking does, as Descartes stated. If you don’t act (in the broadest sense), you are not. Or as Korsgaard says (p. 100): “The intimate connection between person and action does not rest in the fact that action is caused by the most essential part of the person, but rather in the fact that the most essential part of the person is constituted by her actions.” 

Sources
- My blog “I act, therefore I am”, http://philosophybytheway.blogspot.com/2008/03/i-act-therefore-i-am.html

- My blog “ ‘By accident’ and ‘by mistake,’ ”, http://philosophybytheway.blogspot.com/2009/07/by-accident-and-by-mistake.html
- Korsgaard, Christine M, Self-Constitution. Agency, Identity, and Integrity. Oxford: Oxford University Press, 2009
- O’Mara, Shane, In praise of walking. London: The Bodley Head, 2019