Not all philosophical cleverness and sophistication is relevant to an understanding of the actual world.
Natural selection is destructive. If being ethical reduces fitness, it will destroy any ethical organism. So, if your ethical theory does not explain how ethical beings endure in a biologically hostile environment, it is worthless. Bentham, Aquinas, Kant, and Aristotle – none of them provides a useful starting point. Contemporary philosophers who follow in their footsteps contribute nothing of value.
Freedom and Responsibility
Do we have free will? The question is whether organisms with specific properties, including an evolutionary and an individual history, are free. The boundaries of the organism are determined by its skin. You cannot use its own properties or its own histories to prove that it is not free. With arguments that appeal to either excluded, it is obvious that we are free enough to be morally responsible. You can get started on an argument against free will only if you reduce individuals to something less than an organism, only if you philosophically alienate their bodies.
Beliefs are not adaptations. There is no natural selection for the beliefs we acquire throughout our lives. What is an adaptation is the capacity to acquire beliefs. The beliefs have to be advantageous to the organism. But advantageousness is not always revealed at the time of acquisition. Instead, it is revealed in the future. Since advantageousness is not detectable in the present, we need a proxy for it. The only plausible proxy is truth as correspondence. Therefore, the correspondence theory of truth is true.