The most important problem that comes up when talking about free will is the difficulty in defining the concept. How exactly do we define free will? There are many definitions with different levels of rigorousness. One way to define free will is in terms of the absolute laws of physics. We can define free will as "the ability of a conscious entity to make choices that are not affected in any way by the events that happened to the conscious entity in the past." This is the definition most often used by the group of people who are classified as incompatibilists. Another way to define it is in terms of other living things. We can define free will as "the freedom to chose which action to take in a particular situation without being hindered by other humans or conscious living beings." My opinion on whether free will exists or not is highly dependent on actual definition being used. I think it is extremely unlikely (and even impossible on principle) to have the kind of free will that is independent of influence from physical law. However if the definition on free will does not mention independence from past events and only concerns itself with restrictions on choices we make by other people, then I am willing to accept the possibility of free will existing.
In the second kind of definition, we are merely stating that when faced with a choice such as "Which profession to go into?" or "Which course do I take in college?" we have the freedom to go against the advice of our parents/teachers and do whatever we feel like at the time (not everyone has this freedom ;) ). This kind of freedom in principle exists. Although there are parents that force their children to make certain choices when it comes to college courses, the student can in principle choose not to accept that decision by ignoring or being prepared to accept the - sometimes unpleasant - consequences of their choice. That kind of free will exists and that is the picture of free will that comes to most people's minds when they hear about freedom. In fact, this free will or "social freedom" is the kind of freedom most people expect from modern society. It is what they refer to when they talk about "Freedom of speech" or "Freedom of expression".
However if your definition of free will that tries to say that human decisions are completely independent of the events that took place in your past, I disagree that such a kind of freedom exists. This kind of freedom is impossible to define without generating a contradiction. The human brain is a huge neural network that stores in the neurons different weights that are a result of our past experiences. These are the same neurons that make "conscious" decisions or "choices." I think that it is impossible for a human to make a decision or a choice whose sole originator is the human in question.
Recent results in neuroscience suggest that our conscious "mind" is not really the originator of our actions see: http://www.ncbi.nlm.nih.gov/pubmed/15925808?dopt=Abstract and http://www.ncbi.nlm.nih.gov/pubmed/12191935?dopt=Abstract
The results of these experiments seem to suggest that our "choices" are determined by the brain before our conscious mind becomes aware of the fact that we have made a choice. Results like these reduce the likelihood that the decisions we make are completely independent of past events. It may even be true that the only thing consciousness does is rationalize the involuntary actions of our sub conscious. The very idea that we have "Made a decision" may be an illusion in many situations.
I also disagree with people who simply wave their hands vaguely and say free will exists because Quantum Mechanics. While it is true that quantum mechanics is a probabilistic theory, it doesn't help to "gift" free will to consciousness. Firstly it is highly dubious whether quantum mechanics is directly involved in human cognition and consciousness. Secondly even if quantum mechanics made our choices probabilistic it still doesn't mean that the decisions are free decisions. Decisions can only be classified as "free" if a people have the same probability of making a particular decision when faced with a particular choice independent of the experiences these people have had in the past. A coin that lands on heads half the time does not have "free will".
I think a lot of the confusion surrounding the debate about free will and determinism is because of the wide variety of ways in which people define "Free will". It's got so many definitions that it is impossible to say what people mean when they say "I believe in Free will". If someone ever says that the very first thing I will do is to ask them how they define free will. The debate should be pretty straightforward from that point on.
In the second kind of definition, we are merely stating that when faced with a choice such as "Which profession to go into?" or "Which course do I take in college?" we have the freedom to go against the advice of our parents/teachers and do whatever we feel like at the time (not everyone has this freedom ;) ). This kind of freedom in principle exists. Although there are parents that force their children to make certain choices when it comes to college courses, the student can in principle choose not to accept that decision by ignoring or being prepared to accept the - sometimes unpleasant - consequences of their choice. That kind of free will exists and that is the picture of free will that comes to most people's minds when they hear about freedom. In fact, this free will or "social freedom" is the kind of freedom most people expect from modern society. It is what they refer to when they talk about "Freedom of speech" or "Freedom of expression".
However if your definition of free will that tries to say that human decisions are completely independent of the events that took place in your past, I disagree that such a kind of freedom exists. This kind of freedom is impossible to define without generating a contradiction. The human brain is a huge neural network that stores in the neurons different weights that are a result of our past experiences. These are the same neurons that make "conscious" decisions or "choices." I think that it is impossible for a human to make a decision or a choice whose sole originator is the human in question.
Recent results in neuroscience suggest that our conscious "mind" is not really the originator of our actions see: http://www.ncbi.nlm.nih.gov/pubmed/15925808?dopt=Abstract and http://www.ncbi.nlm.nih.gov/pubmed/12191935?dopt=Abstract
The results of these experiments seem to suggest that our "choices" are determined by the brain before our conscious mind becomes aware of the fact that we have made a choice. Results like these reduce the likelihood that the decisions we make are completely independent of past events. It may even be true that the only thing consciousness does is rationalize the involuntary actions of our sub conscious. The very idea that we have "Made a decision" may be an illusion in many situations.
I also disagree with people who simply wave their hands vaguely and say free will exists because Quantum Mechanics. While it is true that quantum mechanics is a probabilistic theory, it doesn't help to "gift" free will to consciousness. Firstly it is highly dubious whether quantum mechanics is directly involved in human cognition and consciousness. Secondly even if quantum mechanics made our choices probabilistic it still doesn't mean that the decisions are free decisions. Decisions can only be classified as "free" if a people have the same probability of making a particular decision when faced with a particular choice independent of the experiences these people have had in the past. A coin that lands on heads half the time does not have "free will".
I think a lot of the confusion surrounding the debate about free will and determinism is because of the wide variety of ways in which people define "Free will". It's got so many definitions that it is impossible to say what people mean when they say "I believe in Free will". If someone ever says that the very first thing I will do is to ask them how they define free will. The debate should be pretty straightforward from that point on.