Nature is one big machine and the entire machine is driven by “causality” - the law of cause and effect. This means that regarding nature, if I know every condition that exists at any given moment, I can predict exactly what will happen next.
For instance, if I drop a ball from a certain height, I can predict exactly how fast and hard it will fall. The same applies to everything in nature. If I know all the causes, I will know all the effects ... every single time.
A plant, for instance, is completely connected to its environment so that everything that will happen to it is predetermined by that environment. If I know how much sunlight it will be exposed to, how much water it will receive, and every other variable, I will know exactly whether, and to what degree, it will thrive or whither. It is all cause and effect.
Even animals operate the same way. Free choice is the exclusive domain of humans; animals act on instinct. Their reactions are locked in. If we theoretically knew all the internal and external conditions at any given moment, we could predict an animal’s behavior at the next moment. Their conduct is “hardwired.” It is predetermined and thus completely part and parcel of nature. It is all one big, interconnected machine.
On a certain level we humans are the same. We have within us a nefesh habehamis, an “animal spirit” that is impulsive, that reacts to stimuli in much the same way an animal does. Place any stimulus, say a slice of pizza, in front of us, and the nefesh habehamis, our animal instinct, will automatically be triggered and we will reach to take it.
If we behave this way, if we mindlessly follow our impulses, we are no different from animals. We are part and parcel of nature and completely connected and determined by our surroundings. We are part of the “machine.”