I have written often on the “is/ought dichotomy” or “Hume’s Dilemma” (look these up on Wikkipedia, if you like) but here goes again. Ayn Rand claimed to have solved this long-standing philosophical problem, but most other thinkers have concluded that she did not do so.
As a Plotonist, I think that for there to be an “ought” there must be a purpose or end in view. “Ought” is always about what is good to do and what is good to do is good to do because it obtains some “good” or “valuable commodity” or “beneficial/favourable effect”. Now, it would seem that without a choice there cannot be an end and so there can be no good; because what is good or valuable is always good in as far as it is valuable for some objective. Technically, “good” is teleological: in other words “good is utility”.
The problem with this position is that it gives no account of how a choice might be made. Without such an account it degrades into Existentialism, in which value is understood as entirely subjective and somehow created by the individual person: who is themselves understood as valueless except by virtue of some kind of choice to be valuable. This position is incoherent, as what is of itself of no value (in this case the human person) cannot create value by a mere act of whimsy.
The fact that rats are of utility to the bubonic plague bacterium in spreading it to other hosts does not make rats valuable as such. In fact, from a human perspective, it makes rats un-valuable and the project of their extermination a desirable good. Conversely, from the rat perspective, human ignorance about their role in the epidemiology of the Black Death is a desirable end – though how this great “good” might be achievable by the rat commonality is unclear.
I think that the solution to the is/ought dichotomy is something along the lines of Ayn Rand’s proposal, but that one needs to augment her position somewhat. The first thing to realise is that “ought” and “goal” and “good” and “utility” all arise from the nature of Life. These words only have application in the context of a living being. Only a living being can have any “goal” and nothing can possibly be “good for” any other thing – unless that other thing is alive. While one might say that a carefully controlled humidity and temperature are “good for” the preservation of ancient manuscripts, this is only an analagous use of the term – and it would not arise except in the context that living beings had first constructed those manuscripts and that other living beings were interested in their preservation.
This first realisation makes one focus on the fact that “ought” is not a word of general applicability, but only of applicability within the context of life. This is not an additional axiom, it is simply a realisation of the underlying significance of the concept. This is basically the realisation which Ayn Rand came to see and then promoted as the answer to Hume’s Dilemma. She argued that “ought” could always be reduced to a choice to live; and to live in accordance with the nature that one had, making full use of one’s capabilities so as to best secure, facilitate, establish and fortify one’s life.
The second thing to realise is what life is. Without this realisation, Ayn Rand’s solution to Hume’s Dilemma can be deconstructed along the lines: “But why should any living agent chose to live?” I propose that: “Life is continuance and stability of form in and by virtue of and out of flux.”
This is relevant to Hume’s dilemma in an almost trivial way. Just as “ought” originates from life, so if one chooses to do what one “ought not” then one will not live. The only basic choice, therefore, is between life and death. It is true, in an uninteresting way, that this choice is real and that it is not motivated by anything other than the outcome in question; but that is exactly the point! If one chooses life one lives, if one chooses death one dies. Those that chose death and die have no existence, whereas those that chose life and live do have existence. This is the basic fact of the matter and is entirely objective and unavoidable.
As to why one ought to chose life: that is easy – to do so is coherent: logically consistent. Life’s constitutional business is to survive: that is what life is all about. Survival is definitional of life in the way that no other of its supposed/proposed characteristics are. For life to chose death is incoherent and self-contradictory and results in life ceasing to be itself. All living beings which chose death cease to be living beings, so the only choice possible for a living being is the choice of life: in fact death is not a choice for a living being!
The deeper question: “Why should a conscious living being wish to continue to live, especially if they are unhappy and believe themselves to have no prospect of joy?” remains, but I am not inclined to tackle this here and now.