Thomas Nagel

To explain consciousness, a physical evolutionary history would have to show why it was likely that organisms of the kind that have consciousness would arise.

One of the legitimate tasks of philosophy is to investigate the limits of even the best developed and most successful forms of contemporary scientific knowledge. It may be frustrating to acknowledge, but we are simply at the point in the history of human thought at which we find ourselves, and our successors will make discoveries and develop forms of understanding of which we have not dreamt. Humans are addicted to the hope for a final reckoning, but intellectual humility requires that we resist the temptation to assume that tools of the kind we now have are in principle sufficient to understand the universe as a whole. Pointing out their limits is a philosophical task, whoever engages in it, rather than part of the internal pursuit of science—though we can hope that if the limits are recognized, that may eventually lead to the discovery of new forms of scientific understanding. Scientists are well aware of how much they don’t know, but this is a different kin

lieve the weight of evidence favors some form of neutral monism over the traditional

In fact most of the time you don't even think about the mental states that make you aware of those things: you seem to be aware of them directly. But how do you know they really exist?

Knowledge of minds other than our own
The relation between mind and brain
How language is possible
Whether we have free will
The basis of morality
What inequalities are unjust
The nature of death
The meaning of life

There may or may not be an external world, and if there is it may or may not be completely different from how it seems to you -- there's no way for you to tell. This view is called skepticism about the external world.

Would things seem any different to you if in fact all these things existed only in your mind -- if everything you took to be the real world outside was just a giant dream or hallucination, from which you will never wake up?

The most radical conclusion to draw from this would be that your mind is the only thing that exists. This view is called solipsism.

The main concern of philosophy is to question and understand very common ideas that all of us use every day without thinking about them. A historian may ask what happened at some time in the past, but a philosopher will ask, "What is time?" A mathematician may investigate the relations among numbers, but a philosopher will ask, "What is a number?"