In addition, so is metaphysical solipsism, effectively dead! Methodological solipsism, may not be (there’s a difference) so hang on.
Cartesian Dualism covers a similar mind-body dichotomy concepts as posed in Adhyatma or Bedanta in the Vedas or Buddhism (In almost every spiritual faith system). So we do not have to give each theological variety a special consideration or a higher ground in philosophy, as the core idea is like that in Cartesian Dualism itself.
The mind (consciousness) as we know today, is a product of observable, material phenomenons involving sodium, calcium, chloride, neurotransmitters, action potentials, neurons, nerves and their intricate arrangements and their interplay with myriads of different kinds of external stimuli. This much is already too certain to not be considered for explaining the origin of the mind (but unfortunately not enough for explaining as to how it works), as the evidence is heavy. Let’s try to find consciousness without these shall we? Or injure a brain-stem region and not be unconscious? Or alternatively, let’s try to code for a supposedly self aware AI without silicon chips, circuits, photons and electricity. We cannot even fathom such feats can we?
Back in the time of Descartes or even before that, say during the period of inception of the great spiritual faiths, this much was not known so their idea of dualism is understandable and intuitive. Nonetheless, empirical evidence is counter-intuitive and possibly the reason why dualism still lingers around much of the philosophical community. I admit, sadly, that critical understanding of philosophy, without confirmation biases is hard and the idea of dualism, despite of being fallacious is pleasing.
Now Metaphysical Solipsists and Idealists will argue that observable evidence is also a result of our conditioning and experience (subjectivity) so cannot be relied upon, but that is a circular argument, such that this doesn’t explain that if reality were to be a product of our minds, why others around us experience similar subjective things not much differently than we as ‘self’ do? Cognitive science can study subjectivity better and better with each passing day and has been producing observable, reproducible results with a considerable degree of universality. So the idea that subjectivity cannot be studied rationally is long expired.
In this respect Idealism, Dualism and metaphysical solipsism will not carry much ground for the purpose of explaining the nature of our consciousness. I repeat, useless for the purpose of explaining but useful for the purpose of questioning, since philosophy can be considered as the art of questioning. It’s not, as a whole, completely dead like Stephen Hawkins and some notable physicists have declared. Philosophy may not be useful for answering the questions it asks, but it is also important to remind ourselves that formulation of every hypothesis follows questioning borne out of curiosity. It is again vital to understand, that curiosity cannot on itself answer or satisfy the questions it asks. So a system or a method is required, to rid the observer of subjective biases and conditioning that could skew their empirical observation.
Now some philosophers like to interpret Dualism with today’s scientific understanding, as in relating the mind body dichotomy to highlight the bridge between subjectivity and objectivity. In my opinion, that may be understandable for many intellectuals, but I think it falsely justifies an ingenious but an expired idea. I think we can find better ways to ask questions about the nature of the Qualia or simply our experiences borne out of our subjective perceptions without obscuring the already clear link between the brain and the mind.
To sum up, I think instead of dedicating our time and effort to revolve around in the circular arguments posed by dated concepts like dualism, philosophers and scientists may better utilize their resources and time, if important questions about the very details of the origins of the consciousness and it’s functions is asked instead.