7. Extreme versions of free will and determinism are just that - extreme. The truth lies in the middle and is easier to understand when timescales are introduced. In the short-term, on biological timescales such as those concerning biochemistry, molecular biology, and cellular biology, events are determined by their current states. In the medium-term, on biological timescales such as those concerning organismic biology, and sociobiology, free will is not only possible, it determines the states that arise in the short-term and the long-term. In the long-term, on biological timescales such as those concerning ecology and evolutionary biology, the characteristics of competitiveness, cooperativeness, and adaptability are required for survival. In that sense, the long-term is determined. The free will that occurs in the medium-term, and the randomness of destructive cosmological events, means that who survives is unknown. Evolution is blind. We are not.
First, let me say a few words to dispatch the extreme versions of free will and determinism. Even the most ardent supporter of free will recognizes that our actions and beliefs come from something. Whether they come from our genes, our environment, our family, our friends, our personal reflection, our reading, or our previous choices, nothing that we produce can be said to be "free" from all influence. Even new inventions are simply the combination and rearrangement of what has come before in order to construct something different (aka the mating of ideas). This is simply a characteristic of our rational universe - no effects occur without a cause. Therefore, it is easy to dismiss the extreme position for free will that states we are "free to do whatever we want" because there are definite constraints placed on us by the universe we live in.
Now, the other extreme of this problem is to state that since everything has a cause, then if we were only smart enough, we could calculate all the influences, weigh them up, and know everything that would happen - the universe and our actions within it would be determined. This is an appealing argument to the rational-minded among us. It seems to flow naturally from investigations into chaos theory, which prove, for example, that if only we knew all the tiny variations in starting conditions and physical influences, then we could understand all the irregularities of planetary orbits or we could predict the weather with astonishing accuracy. Those examples may be true, but humans are not dead objects subjected only to the physical forces of the universe. We are living organisms influenced by our internal emotions to act to stay alive. However, since our emotions are momentary chemical reactions that can be fooled into preferring short-term fixes to long-term solutions, we evolved the power of reason to break free from the determinism of emotional pull. Those of us that learned to correctly weigh the complex choices we face, that were able to endure short-term pains for long-term gains, that were able to ignore powerful base urges for the benefit of subtler lasting pleasures - we were the ones who survived and passed on this remarkable ability. And this ability became unevenly distributed within the population so that some of us are quite conforming to our emotional pulls and some of us are quite rebellious against them. So yes, all of our actions may be said to be influenced by something, but if one of those things is our own nature, which includes an ability to ignore a majority of our influences, then this element of choice is as good as throwing a random variable into any equation of determinism, thus defeating its predictions. One of my favorite passages in literature illustrates this concept beautifully. It came from Dostoevsky in 1864 in his short novel Notes from Underground. See the quote below for his perceptive understanding of human nature.*
So if the extreme versions of free will and determinism are discarded, what is in the middle? Just the practical view that we are influenced, but we have choice. We don't have the freedom to do whatever we want, but we could do anything we can. We aren't free from the constraints of the universe, but the universe doesn't care what we do inside it. We aren't free to stop our cells from metabolizing the food we eat, but we are free to not destroy the ecosystems we rely upon for its production. In short, we are free to choose actions that lead to our survival or extinction, and that choice of outcome is obvious. How we get there is the tricky part, but philosophy can guide us.
* "…you say, science itself will teach man that he never had any caprice or will of his own, and that he himself is something of the nature of a piano key or the stop of an organ, and that there are, besides, things called the laws of nature; so that everything he does is not done by his willing it, but is done of itself, by the laws of nature. Consequently we have only to discover these laws of nature, and man will no longer have to answer for his actions and life will become exceedingly easy for him. All human actions will then, of course, be tabulated according to these laws, mathematically, like tables of logarithms up to 180,000, and entered in an index; or better still, there would be published certain edifying works of the nature of encyclopaedic lexicons, in which everything will be so clearly calculated and explained that there will be no more incidents or adventures in the world.
Then - this is all what you say - new economic relations will be established, all ready made and worked out with mathematical exactitude, so that every possible question will vanish in the twinkling of an eye, simply because every possible answer to it will be provided. Then the "Palace of Crystal" will be built. Then...in fact, those will be halcyon days. Of course there is no guaranteeing (this is my comment) that it will not be, for instance, frightfully dull (for what will one have to do when everything will be calculated and tabulated), but on the other hand everything will be extraordinarily rational. Of course boredom may lead you to anything. It is boredom that sets one sticking golden pins into people, but that would not matter. What is bad (this is my comment again) is that I dare say people will be thankful for the golden pins in them. Man is stupid, you know, phenomenally stupid; or rather he is not at all stupid, but he is so ungrateful that you could not find another like him in all creation. I, for instance, would not be in the least surprised if all of a sudden, a propos of nothing, in the midst of general prosperity a gentleman with ignoble, or rather with a reactionary and ironical countenance were to arise and, putting his arms akimbo, say to us all: "I say, gentlemen, hadn't we better kick over the whole show and scatter rationalism to the winds, simply to send these logarithms to the devil, and to enable us to live once more at our own sweet foolish will!" That again would not matter, but what is annoying is that he would be sure to find followers - such is the nature of man. And all of that for the most foolish reason, which, one would think, was hardly worth mentioning: that is, that man everywhere and at all times, whoever he may be, has preferred to act as he chose and not in the least as his reason and advantage dictated. And one may choose what is contrary to one's own interest, and sometimes one positively ought (that is my idea). One's own free unfettered choice, one's own caprice, however wild it may be, one's own fancy worked up at times to frenzy - is that very "most advantageous advantage" which we have overlooked, which comes under no classification and against which all systems and theories are continuously being shattered to atoms. And how do these wiseacres know that man wants a normal, a virtuous choice? What has made them conceive that man must want a rationally advantageous choice? What man wants is simply independent choice, whatever that independence may cost and wherever it may lead. And choice, of course, the devil only knows what choice."
-- Fyodor Dostoevsky, Notes From Underground, published in 1864