In the 1970’s, Benjamin Libet conducted a series of studies that aimed to provide a timing of consciousness. A subject was asked to look at an oscilloscope timer with a moving dot and voluntarily press a button within a certain timeframe. The results showed that there was unconscious activity within the brain signaling the readiness potential for the voluntary action 300 milliseconds before the subject reported being conscious of it. These and other related studies have produced similar results. Obviously, they have been used by free will skeptics to claim that so-called voluntary actions are really caused unconsciously without our knowledge.
The problems with this conclusion are many and better put by others:
“The all too natural vision that we must discard is the following: somewhere deep in the brain an act-initiation begins; it starts out as an unconscious intention, and slowly makes its way to the theater, picking up clarity and power as it goes, and then, at an instant, t, it bursts on stage, where a parade of visual spot-representations are marching past, having made their way slowly from the retina, getting clothed with brightness and location as they moved. The audience or I is given the task of saying which spot-representation was "on stage" exactly when the conscious intention made its bow. Once identified, this spot's time of departure from the retina can be calculated, as well as the distance to the theater and the transmission velocity. In that way we can determine the exact moment at which the conscious intention occurred in the Cartesian theater.” -Time and The Observer: The Where and When of Consciousness in the Brain by Daniel Dennett and Marcel Kinsbourne
Of course, unfazed by these types of objections there are still some free will skeptics that point to neuroscience and claim that I don’t have free will because “my brain made me do it”.
These claims, as Dr. Raymond Tallis eloquently puts it are “premature”.