Question

Hello!
I heard a lecture by the Rabbi in which he said that if a Jew who does not accept God and does not believe in His commandments performs a commandment, such as putting on tefillin or joining a prayer quorum, this does not have the validity of fulfilling a commandment.
Now I heard in Dogmatics 4 an explanation of Maimonides that one can explain Maimonides as viewing the commandments as laws. (This explains why he refers to the laws of ritual impurity as a commandment, even though there is no command or prohibition to become impure.)
In light of this interpretation, can one say that a secular Jew who observed a commandment that he does not believe in is nevertheless considered to have fulfilled a commandment, since he carried out the law?