Education Department special assistant Eileen Marie Gardner yesterday defended her controversial position that federal aid for the handicapped has been "misguided," saying that if people are disabled, "it was not a cruel act of fate . . . it's from God."

In a tense and emotionally charged hearing crowded with disabled spectators in wheelchairs, Sen. Lowell P. Weicker Jr. (R-Conn.) -- father of a child with Down's syndrome -- led Gardner through an unusual public revelation of her private convictions, although he repeatedly said that Gardner's religious beliefs were "not my business."

Gardner raised the ire of Weicker and others with a statement in a draft position paper for the Heritage Foundation that said, "There is no injustice in the universe. As unfair as it may seem, a person's external circumstances do fit his level of internal spiritual development. The purpose (and the challenge) of life is for a person to take what he has and to use it for spiritual growth."

At yesterday's hearing, held by the appropriations subcommittee overseeing education policy, Weicker said that after newspapers published Gardner's remark, he received a telephone call expressing "indignation" from Sarah Brady, wife of White House press secretary James S. Brady, who was wounded in an assassination attempt on President Reagan. "Do you think Jim Brady's external circumstances fit his level of inner spiritual development?" Weicker asked.

Gardner replied, "That is in no way to assume that a person is inferior or bad. I'm saying that what happens to a person in life, the circumstances a person is born into -- the race, the handicapped issue, sex, whatever -- those circumstances are there to help the individual grow towards internal spiritual perfection."

Gardner, who holds a doctorate in education from Harvard's graduate school of education, insisted that she would not be advising the Education Department on issues of religion or theology. But in terms of educational policy, she said she believes "the underlying philosophy of some of the handicapped rests on the belief that there is no universal order -- that what happened to them is due to chance, fate, some cruel fate." She said those "falsely based" feelings "fueled the efforts to take care of the handicapped" for two decades. But with a limited amount of education funds available, she said, "it is reasonable to think about how much the handicapped . . . can profit from education."

The other newly appointed Education Department official, Lawrence A. Uzzell, also raised Weicker's anger when he stood by a 1983 statement that every federal program for secondary and elementary education -- including the "Education for All Handicapped Children Act" of 1975 -- should be abolished, leaving the Education Department a statistics-gathering agency.

Uzzell said the problem with education during the past two decades has been an overcentralization of programs in Washington. "You cannot separate . . . the well-being of handicapped children from the fact that SAT scores were going down every single year from 1963 to 1980," he said.

Both officials said their views are personal and do not represent the official position of the department. Even so, Education Secretary William J. Bennett moved quickly to distance himself from the remarks of the aides. He issued a statement saying he "reaffirmed" his commitment to programs for the disabled and promised to "aggressively enforce these regulations to the fullest extent of the law." Uzzell "was representing his own personal views at the hearing . . . this administration is committed to supporting the education of the handicapped," Bennett said.

Fifteen groups representing the disabled signed a telegram to Reagan calling for Gardner's firing. Also, Rep. Tony Coelho (D-Calif.), who suffers from epilepsy, called for her ouster.