The signal-using organism has an environment.
The sign-user has an environment, but it also has a world.
The environment of an organism is those elements of the Cosmos which affect the organism significantly (Saturn does not) and to which the organism either is genetically coded to respond or has learned to respond. There are many gaps in an environment, i.e., there are elements which are without significant effect. A honey bee takes account of the bee dance of another bee indicating the direction and distance of a nectar source, but not of a grouse dance.
The sign-user has a world.
The world is segmented and named by language. All perceived objects and actions and qualities are named. Even the gaps are named—by the word gaps. An African Bushman has hundreds of names for plants which are either noxious or medicinally beneficial. But he also has a word bush to name all other plants. The Cosmos is accounted for willy-nilly, rightly or wrongly, mythically or scientifically, its past, present, and future. All men in all cultures know what is under the earth, what is above the earth, and where the Cosmos came from.
The environment has gaps. But the world of the sign-user is a totality. The Cosmos is totally construed by signs, whether the signs be the myth of Tiamat, Newtonian cosmology, or through the auspices of such popular signifiers as “outer space,” “out there,” “the heavens,” “the sky,” “stars,” and so on.
Not all items of an environment are part of the world. A noxious element—say, an increase in ultraviolet radiation—is a significant environmental factor and may cause skin cancer. But it is unknown to the patient and not part of his world. But the signs unicorn and boogerman may be very much a part of a person’s world and yet have no known counterpart in the Cosmos.
Note some odd things about the self’s world. One is that it is not the same as the Cosmos-environment. The planet Venus may be a sign in the self’s world as the evening star or the morning star, but the galaxy M31 may not be present at all. Another oddity is that the self’s world contains things which have no counterpart in the Cosmos, such as centaurs, Big Foot, détente, World War I (which is past), World War III (which may not occur). Yet another odd thing is that the word apple which you utter is part of my world but it is not a singular thing like an individual apple. It is in fact understandable only insofar as it conforms to a rule for uttering apples. But the oddest thing of all is your status in my world. You—Betty, Dick—are like other items in my world—cats, dogs, and apples. But you have a unique property. You are also co-namer, co-discoverer, co-sustainer of my world—whether you are Kafka whom I read or Betty who reads this. Without you—Franz, Betty—I would have no world.